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Syntheses and characterization of four novel monooxovanadium(v) hydrazone complexes with hydroxamate or alkoxide ligand
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Pergamon PII] S9166Ð4276"87#99043Ð4
Polyhedron Vol[ 06\ No[ 19\ pp[ 2484Ð2595\ 0887 Þ 0887 Elsevier Science Ltd All rights reserved[ Printed in Great Britain 9166Ð4276:87 ,08[99¦9[99
Syntheses and characterization of four novel monooxovanadium"v# hydrazone complexes with hydroxamate or alkoxide ligand Shan Gao\ Zhi!Qiang Weng and Shi!Xiong Liu Dept[ of Chem[\ Fuzhou University\ Fuzhou 249991\ P[ R[ China "Received 2 December 0886^ accepted 5 April 0887# Abstract*Four novel monooxovanadium"V# hydrazone complexes\ ðVOL0"Hshi#Ł "0#\ ðVOL0"bz#Ł "1#\ ðVOL1"bz#Ł=CH1Cl1 "2#\ and ðVOL1"OCH2#"CH2OH#Ł=CH2OH "3# "H1L0 salicylaldehyde benzoylhydrazone\ H1L1 o!vanillin benzoylhydrazone\ H1shi salicylhydroxamic acid\ Hbz benzohydroxamic acid#\ were pre! pared and characterized by IR\ Raman\ UV\ 0H NMR spectra\ cyclic voltammetry measurements and X!ray di}raction[ The geometry around the vanadium atoms is a distorted VO"ONO#"OO# octahedron in complexes 0\ 1 and 2\ while the geometry is a distorted VO"ONO#"O#"O# octahedron in 3[ The V1O bond distance is for complexes 0\ 1\ 2 and 3\ respectively[ In complexes 0\ 1 and 2\ 0[463"3#\ 0[482"4#\ 0[483"3# and 0[466"3# A the O\ N\ O atoms of a tridentate hydrazone ligand and one oxime oxygen atom of a bidentate hydroxamate ligand are coordinated to the vanadium"V# atom\ forming an equatorial plane[ In complexes 0\ 1 and 2\ the axial position trans to the oxo group is occupied by the carbonyl oxygen atom of the hydroxamate ligand\ but not by the oxime oxygen atom[ The bond distances in the equatorial plane in the title complexes follow the order] alkoxide oxygen³phenoxide oxygen\ oxime oxygen³enolic oxygen³imine nitrogen[ The complexes 0\ 1 and 2 represent the _rst structural examples of vanadium complexes containing both hydrazone and hyd! roxamate ligands[ Þ 0887 Elsevier Science Ltd[ All rights reserved Keywords] monoxovanadium"V# complexes^ hydrazone complexes^ hydroxamate complexes^ crystal structures^ spectroscopic properties[ ———————————————————————————————————————————————
Knowledge of the biological role of vanadium as a trace element has considerably increased over the past decade ð0\ 1Ł[ A vanadium enzyme has been described which exhibits histidine!nitrogen coordination to vanadium ð2Ł[ The active sites of some biological enzymes include the hydroxamic acids ð3Ł[ Many small biomolecules such as hydroxy! or mercap! tocarboxylates\ amino acids\ hydroxamates\ hydra! zones\ phosphates\ phosphonates\ catechol derivatives\ etc[ are able to bind this element rather strongly in both the ¦3 and ¦4 oxidation states ð4Ð 04Ł[ However\ only a few structures of the simplest vanadium complexes with hydroxamate ligands have been studied ð4\ 05Ð07Ł[ Up to now\ only a few oxov! anadium hydrazone complexes have been reported[ These hydrazone complexes are only limited to dioxovanadium"V# complexes with VO1"ONO# coor!
Author to whom correspondence should be addressed[
dination ð7\ 08Ð10Ł\ and to monooxovanadium"V# complexes with square pyramidal VO"ONO#"O# coor! dination ð09\ 11Ð16Ł and octahedral "VO"ONO#"O#"O# ð17Ł or VO"ONO#"ON# ð8\ 04Ł coordination[ The relationships between structure\ spectroscopy\ and reactivity must be elucidated in order to under! stand fully the role of vanadium in biological systems[ We have undertaken the syntheses and charac! terization of some vanadium compounds containing tridentate ligand with VO"ONO#"ON# or VO"ONO#"OO# coordination ð04\ 18Ł[ Herein we report four monooxovanadium"V# hydrazone com! plexes with the hydroxamate or alkoxide ligand\ ðVOL0"Hshi#Ł "0#\ ðVOL0"bz#Ł "1#\ ðVOL1"bz#Ł=CH1Cl1 "2#\ and ðVOL1"OCH2#"CH2OH#Ł=CH2OH "3# "H1L0 salicylaldehyde benzoylhydrazone\ H1L1 o! vanillin benzoylhydrazone\ H1shi salicylhydroxamic acid\ Hbz benzohydroxamic acid#[ To the best of our knowledge\ the complexes 0\ 1\ and 2 are the _rst examples of vanadium hydrazone complexes with VO"ONO#"OO# coordination[
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Shan Gao et al[ EXPERIMENTAL
Materials The materials VO"acac#1 "acac acetylacetonate#\ Hbz and H1shi\ were synthesized according to refer! ences ð29\ 20Ł\ respectively[ The ligand H1L0 was pre! pared by condensing salicylaldehyde with equimolor benzoylhydrazine in ethanol[ The ligand H1L1 was synthesized by condensing o!vanillin with equimolor benzoylhydrazine in ethanol[ Analytically pure dichloromethane was distilled over calcium hydride before use[ All other analytical grade chemicals and solvents were purchased commercially and used with! out further puri_cation[
Synthesis of ðVOL0 "Hshi#Ł "0# ðVO"acac#1Ł "9[152 g\ 0[99 mmol# dissolved in 09 cm2 methanol was added dropwise to a methanol solution containing 9[139 g "0[99 mmol# of H1L0 with stirring\ and then the mixture was heated at re~ux with stirring for 0 h and cooled to room temperature[ 09 cm2 of mixed solution of methanol and salicylhydroxamic acid "0 mmol# was slowly added to the above red! black solution[ The reaction mixture was stirred for 29 min[ and _ltered[ Then deep red solid was dissolved in the dichloromethane and _ltered[ The deep red crystals of the complex 0 were obtained by slow di}usion of hexane into the _ltrate for several days and collected under vacuum over P3O09[
0
Synthesis of ðVOL "bz#Ł "1# The synthesis of complex ðVOL0"bz#Ł "1# was anal! ogous to that of complex 0\ only except that sali! cylhydroxamic acid was replaced by benzohydroxamic acid[ The deep red crystals of the complex 1 were formed upon slow evaporation of the _ltrate for several days and collected under vacuum over P3O09[
Synthesis of ðVO"L1#"bz#Ł=CH1Cl1 "2# A 04 cm2 CH2OH solution of VO"acac#1 "9[152 g\ 0[99 mmol# was added dropwise to a 04 cm2 CH2OH solution of H1L1 "0[99 mmol#[ The mixture was re~uxed with stirring for 0[4 h\ cooled to room tem! perature[ A 09 cm2 solution of benzohydroxamic acid "0[99 mmol# in CH2OH was added to the above dark red solution[ The mixture was stirred for 29 min[ and _ltered[ The red brown solid was dried under vacuum over P3O09 for 1 days\ dissolved in the dichlo! romethane and _ltered[ The deep red crystals of the complex 2 were isolated by slow di}usion of hexane into the above _ltrate for several days and collected under vacuum over P3O09[
Synthesis of ðVO"L1#"OCH2#"CH2OH#Ł=CH2OH "3# To H1L1 "0[99 mmol# dissolved in 04 cm2 CH2OH was added VO"acac#1 "9[152 g\ 0[99 mmol# in 04 cm2 CH2OH[ The mixture was re~uxed with stirring for 0 h\ cooled to room temperature and _ltered[ The deep red crystals of the complex 3 were obtained by slow evaporation of the deep red _ltrate at room tem! perature in a few days\ and then collected under vac! uum over P3O09[ Physical measurements IR spectra and Raman spectra were measured on a Nicolet Magna 649 Fourier transform IR spec! trometer and a Nicolet Raman 809 Fourier transform laser!Raman spectrometer\ respectively[ UV!vis spec! tra were obtained on a Perkin!Elmer lambda 8 UV:vis:near!IR spectrometer in CH1Cl1 solution and in the 299Ð0999 mm range[ 0H NMR spectra were collected on a Varian FT!79A spectrometer in CDCl2\ using TMS as internal standard[ Electrochemical measurements were undertaken on a BAS 099 A elec! trochemical analyzer on CH1Cl1 solution "0 mM com! plex\ 9[0 M "Et3N#ClO3#[ A three!electrode system was composed of a platinum working electrode\ a plati! num wire auxiliary electrode\ and a Ag:AgCl reference electrode[ X!ray structure determination X!ray di}raction data were recorded on a Rigaku AFC4R di}ractometer with graphite!mon! #\ the ochromated MoÐKa radiation "l 9[60958 A scan mode being v!1u[ Cell dimensions were re_ned using 14 re~ections in the ranges 19³1u³29>[ The di}raction data were corrected for Lorentz e}ect and polarization e}ect for the title complexes[ The crys! tallographic data are given in Table 0[ The structures were solved by direct methods and re_ned by a full!matrix least!squares procedure[ All non!hydrogen atoms were re_ned with anisotropic thermal parameters[ All hydrogen atoms were located by di}erence Fourier map or HYDROGEN program and added to the structure factor calculation\ but their positions were not re_ned[ RESULT AND DISCUSSION Spectroscopic studies Table 1 summarizes the IR and Raman spectra data of the free ligands and the title complexes[ A strong and broad band near 2027½2946 cm−0 is observed in IR spectra of the free ligands and assigned to the n"OH# absorption with hydrogen bond ð21\ 22Ł\ but disappeared in the four title complexes[ The bands at 2123 cm−0 in 0 and at 2047 cm−0 in 3 are due to the
Monooxovanadium"v# hydrazone complexes with hydrazone and hydroxamate
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Table 0[ Crystallographic data Complex
0
1
2
3
Formula Mr Crystal system Space group # a "A # b "A # c "A b "># 2# V "A Z F"999# Dcalc[ "g=cm−2# m Mo Ka "mm−0# Temperature "K# Shape Colour Crystal dimensions "mm# 1umax["># Collected data Unique data Observed data "I×2s"I9## No[ variables R Rw 2# Largest di}[ peak:hole"e:A Max[ shift
C10H05N2O5V 346[21 Monoclinic P10:n 01[747"2# 09[0393"8# 04[599"3# 83[06"1# 1918"0# 3 825 0[49 9[403 187 Prism Deep red 9[29×9[24×9[14 49[1 3990 2711 1062 170 9[940 9[952 9[27:−9[31 9[90
C10H05N2O4V 330[21 Monoclinic P10:a 01[188"4# 7[766"2# 07[760"4# 096[60"2# 0852"0# 3 893 0[38 9[414 187 Rhombus Deep red 9[34×9[34×9[19 49[1 2806 2622 1922 160 9[951 9[974 9[41:−9[28 9[90
C12H19Cl1N2O5V 445[16 Monoclinic P10:n 09[661"2# 19[347"2# 00[827"2# 009[04"1# 1369"0# 3 0025 0[49 9[537 185 Rhombus Deep red 9[29×9[29×9[19 49[9 3636 3386 1384 205 9[959 9[966 9[24:−9[23 9[90
C07H12N1O6V 329[22 Monoclinic P10:a 02[399"3# 6[302"1# 19[481"5# 86[62"1# 1916[9"8# 3 785 0[30 9[400 185 Prism Deep red 9[24×9[14×9[34 49[0 3960 2785 1152 143 9[942 9[957 9[28:−9[34 9[90
ArÐOH absorption in 0 and the coordinated CH2Ð OH absorption in 3\ respectively[ The medium strong bands at 855Ð879 cm−0 "IR# and at 859Ð868 cm−0 "Raman# in these title complexes are attributed to the typical V1O stretching frequencies\ falling within the range of 849Ð889 cm−0 reported for six!coordinated oxovanadium"V# complexes ð8\ 04Ð06\ 18Ł[ The very strong stretching vibrations of n "C1N# and n"C1O# are displaced to lower frequency ð16\ 22Ł\ and the strong n"CÐO# "phenolato oxygen# and the middle n"NÐH# absorption bands in the title complexes dis! play a shift to higher frequency with respect to the free ligands ð04\ 16\ 22Ł[ The new medium bands at 0144Ð0168 cm−0 "IR# and at 0140Ð0167 cm−0 "Raman# may be due to the enolic n"CÐO# absorption ð14\ 18Ł[ It shows that the hydrazone ligands in the title complexes are in a dianionic form of the type "−O½N½O−# and the two hydroxamate ligands are in a monoanionic form of the type "O½O−#[ The stretching vibrations of the VÐO bond and the VÐN bond have been observed at 388Ð244 cm−0 "far!IR#\ and 499Ð245 cm−0 "Raman# ð14Ł[ The 0H NMR spectra data of the free ligands and the title complexes are also shown in Table 1[ As expected\ OÐH and NÐH resonances of the free hydra! zone ligand are absent in the title complexes[ Broad NHÐOH resonances "d 7[66 and 7[89 ppm# of free salicylhydroxamic acid and benzohydroxamic acid
change into a singlet "d 7[87\ 7[85 and 7[82 ppm in 0\ 1 and 2\ respectively# ð22Ł\ indicating the coordination through their deprotonation of the hydroxyl group in the hydroxamate ligand[ In complex 0\ the peak at d 09[75 ppm is assigned to OÐH resonance bonding to aromatic ring of the salicylhydroximate ligand[ In complex 2\ the peak at 4[29 ppm is assigned to CH1 resonance to a dichlormethane molecule[ In complex 3\ the peaks at 4[20 ppm and 2[33Ð2[83 ppm are assigned to H and ÐCH2 resonances of the bonded methanol molecule[ These are agreement with the results of their single crystal analysis[ The LMCT transition "l 343\ 337\ 426 and 381 nm for 0\ 1\ 2 and 3\ respectively# is considered as a charge transfer from a p!orbital on the lone!pair of phenolato or oximate oxygen to the empty d!orbital of vanadium atom[ In contrast to other oxovanadium"V# hydra! zone complexes with 7!quinolinol co!ligand ð18\ 23Ł\ the absorption peaks of the visible region in the title complexes are obviously moved to the UV region[ The other strong bands "l 227\ 224\ 241 and 254 nm in 0\ 1\ 2 and 3\ respectively# are generally attributed to the intraligand absorption peaks ð23Ł[ The other LMCT band observed in the UV region "254 nm in 3\ 241 nm in 2# is due to alkoxo:enolic oxygen bound to vanadium"V# ð23Ł[ As illustrated in Fig[ 0\ there is a quasi!reversible redox behavior corresponding to VV:VIV couple in
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Table 1[ IR "Raman # and 0H NMR spectral data IR "Raman # "cm−0# Compound
n"OH#
Hbz H1Shi H1L0 H1L1 Complex 0
2189 2179 2154 2156 2220
2959 2027 2946 2986 2123
Complex 1
2335
Complex 2
2335
Complex 3
0
n"C1O# 0533 0546 0562 0569 ½0489 "½0435# ½0486 "½0446# ½0459 "½0471#
n"C1N#
n"CÐO#phenolic
n"CÐO#enolic
n"V1O#
n"VÐO#\n"VÐN#
857 "859# 879 "868# 855 "860# 864 "867#
350\244 "340\245# 346\251 "334\251# 387\346\317 "499\345\317# 371\317 "369\309#
CH1Cl1
ÐCH2"CH2OH#
789 0534 0532 0597 "0485# 0597 "0487# 0593 "0485# 0597 "0485#
0168 0168 0241 "0223# 0231 "0229# 0175 "0201# 0235 "0223#
0144 "0142# 0168 "0167# 0148 "0140# 0148 "0151#
NHÐOH
Phenyl
ÐOH"CH2OH#
ArÐOCH2
7[66 7[89
6[15½6[65 5[81½6[82 5[81½7[94 5[77½6[74 5[83½7[96 5[87½7[95 5[87½7[90 6[95½7[05
2047
n"NÐO#
803 "894#
H NMR "d ppm# ArÐOH
Hbz H1Shi H1L0 H1L1 Complex 0 Complex 1 Complex 2 Complex 3
09[37 00[92 8[82 09[75
NÐH
8[71 8[01
The bands at Raman spectra are given in parentheses[
7[87 7[85 7[82
2[82
4[20
2[72 2[85
ÐCH1NÐ
7[42 7[54 7[35 7[37 7[93 7[41
4[29 2[33½2[83
Shan Gao et al[
n"NH#
Monooxovanadium"v# hydrazone complexes with hydrazone and hydroxamate (a)
(b)
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dichloromethane solution in the title complexes[ Their redox potentials in complexes 0\ 1\ 2 and 3 are at E0:1 9[020 V\ 9[959 V\ 9[929 V and 9[227 V with respect to Ag:AgCl\ respectively[ The peak!to!peak separations "rEp of coupled peaks D:E# are 83 mV "0# and 89 mV "1# at a rate of 199 mV s−0[ The E0:1 value of the complex 0 is smaller of 60 mV than that of the complex 1 due to the di}erence between the bidentate hydroximate ligands[ It is noteworthy that the potentials of the VO2¦!VO1¦ couple in the com! plexes 2 and 3 are signi_cantly more positive than those observed for some VO2¦ complexes ð23Ł\ indi! cating that the complexes 2 and 3 are relatively unstable[ Description of the structures of complexes ðVOL0"Hshi#Ł "0#\ ðVOL0"bz#Ł "1# and ðVOL1"bz#Ł = CH1Cl1 "2# The selected bond lengths and angles in complexes 0\ 1 and 2 are listed in Table 2\ Table 3 and Table 4\ respectively[ The molecular structures of complexes 0\ 1 and 2 are shown in Fig[ 1\ Fig[ 2 and Fig[ 3[ There are seven common structural features in the complexes 0\ 1 and 2[
(c)
Fig[ 0[ Cyclic voltammogram of the title complexes 1\ 2 and 3 in dichloromethane "a# complex 1 "b# complex 2 "c# complex 3
"a# The coordination sphere around the vanadium atoms is a distorted octahedral con_guration with ðVVO"ONO#"OO#Ł type[ However\ most of vanadium atoms in the known vanadium hydra! zone complexes have a square pyramidal ðVVO"ONO#"O#Ł coordination ð09\ 11Ð16Ł\ only one complex has octahedral ðVVO"ONO#"O#"O#Ł coordination ð17Ł and two complexes have ðVVO"ONO#"ON#Ł coordination ð8\ 04Ł[ The title complexes 0\ 1 and 2 represent the _rst structural characterization of any vanadium hydrazone complex with VO"ONO#"OO# coordination[ "b# The equatorial plane is formed by the O\ N\ O atoms of the fully deprotonated tridentate hydra! zone ligand "L# and an oxime oxygen atom of the hydroxamate ligand[ The vanadium atom is \ 9[168 A and 9[160 A out the equatorial 9[160 A plane and toward the oxo oxygen atom in the complexes 0\ 1 and 2\ respectively[ "c# The atom lying trans to the oxo oxygen atom "Oo# is the carbonyl oxygen atom "Oc[# of the hydroximate ligand\ but not the oxime oxygen of the same ligand[ It may be related to the structural trans e}ect and the delocalized conjugated system between the V1O unit and the related group in hydroxamic acids[ The trans angle OoÐVÐOc[ is 060[3"1#>\ 061[7"1#> and 069[4"1#> in complexes 0\ 1 and 2\ respectively[ The vanadyl bond of V1O in complexes is 0[463"3#\ 0[482"4# and 0[483"3# A 0 1 and 2\ respectively[ The vanadyl bond length in complex 0 is at the shortest limit of normal V1O bond lengths\ although it is within the range # found in VO2¦ complexes ð04Ð07\ "0[46Ð0[50 A 11Ð17Ł[ In complex 1\ the V1O bond length and \ VÐO"2#"carbonyl# are 0[482"4# and 1[190"4# A
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Shan Gao et al[ # and angles "># for complex ðVOL0"Hshi#Ł "0# Table 2[ Selected bond distances "A V"0#ÐO"5# V"0#ÐO"0# V"0#ÐO"3# V"0#ÐO"1# V"0#ÐN"0# V"0#ÐO"2# O"0#ÐC"0# O"1#ÐC"7# O"4# [[[ N"1a#
0[463"3# 0[731"2# 0[759"2# 0[835"2# 1[989"3# 1[048"2# 0[217"5# 0[291"4# 1[613"4#
O"2#ÐC"04# O"3#ÐN"2# O"4#ÐC"06# N"0#ÐC"6# N"0#ÐN"1# N"1#ÐC"7# N"2#ÐC"04# C"04#ÐC"05# O"5# [[[ N"2b#
0[147"4# 0[261"4# 0[226"5# 0[175"5# 0[393"4# 0[175"5# 0[297"5# 0[369"5# 1[892"4#
O"5#ÐV"0#ÐO"0# O"5#ÐV"0#ÐO"3# O"5#ÐV"0#ÐO"1# O"5#ÐV"0#ÐN"0# O"5#ÐV"0#ÐO"2# O"0#ÐV"0#ÐO"3# O"0#ÐV"0#ÐO"1# O"0#ÐV"0#ÐN"0# O"0#ÐV"0#ÐO"2# O"3#ÐV"0#ÐO"1# O"4#ÐH "11# [[[ N"1a#
87[7"1# 83[7"1# 81[6"1# 096[8"1# 060[3"1# 090[9"0# 047[9"0# 73[0"0# 74[1"0# 85[6"0# 060[1
O"3#ÐV"0#ÐN"0# O"3#ÐV"0#ÐO"2# O"1#ÐV"0#ÐN"0# O"1#ÐV"0#ÐO"2# N"0#ÐV"0#ÐO"2# N"1#ÐC"7#ÐO"1# C"04#ÐO"2#ÐV"0# N"2#ÐO"3#ÐV"0# C"04#ÐN"2#ÐO"3# O"2#ÐC"04#ÐN"2# O"5# [[[ H"12b#ÐN"2b#
044[7"0# 65[8"0# 63[4"0# 75[9"0# 79[9"0# 011[6"4# 000[3"2# 006[0"1# 006[3"3# 005[7"3# 041[7
Symmetry code] a\ x\ 0¦y\ z^ b\ 9[4!x\ −9[4¦y\ 0[4!z[
# and angles "># for complex ðVOL0"bz#Ł "1# Table 3[ Selected bond distances "A V"0#ÐO"4# V"0#ÐO"0# V"0#ÐO"3# V"0#ÐO"1# V"0#ÐN"0# V"0#ÐO"2# O"0#ÐC"0#
0[482"4# 0[736"4# 0[744"3# 0[820"4# 1[945"4# 1[190"4# 0[214"6#
O"1#ÐC"7# O"2#ÐC"04# O"3#ÐN"2# N"0#ÐC"6# N"0#ÐN"1# N"1#ÐC"7# N"2#ÐC"04#
0[297"6# 0[131"6# 0[241"5# 0[174"7# 0[394"6# 0[177"7# 0[205"7#
O"4#ÐV"0#ÐO"0# O"4#ÐV"0#ÐO"3# O"4#ÐV"0#ÐO"1# O"4#ÐV"0#ÐN"0# O"4#ÐV"0#ÐO"2# O"0#ÐV"0#ÐO"3# O"0#ÐV"0#ÐO"1# O"0#ÐV"0#ÐN"0# O"0#ÐV"0#ÐO"2# O"3#ÐV"0#ÐO"1#
099[7"1# 86[6"1# 86[8"1# 86[9"1# 061[7"1# 88[2"1# 042[4"1# 72[7"1# 72[4"1# 85[5"1#
O"3#ÐV"0#ÐN"0# O"3#ÐV"0#ÐO"2# O"1#ÐV"0#ÐN"0# O"1#ÐV"0#ÐO"2# N"0#ÐV"0#ÐO"2# O"1#ÐC"7#ÐN"1# C"04#ÐO"2#ÐV"0# N"2#ÐO"3#ÐV"0# C"04#ÐN"2#ÐO"3# O"2#ÐC"04#ÐN"2#
053[0"1# 64[7"1# 64[3"1# 68[8"1# 78[1"1# 010[8"5# 009[6"3# 007[8"2# 006[9"4# 006[4"5#
which are longer than the corresponding bond distances of the complex 0[ It may be related to the di}erence between hydroxamate ligands in these two complexes[ "d# The four VÐO or VÐN bond distances in the equa! torial plane follow the order] alkoxide oxy! gen³phenoxide oxygen\ oxime oxygen³enolic oxygen³imine nitrogen[ The bond length of V"0#ÐO"1# "enolic oxygen# in complex 0 is ½9[0 A longer than that of the V"0#ÐO"0# "phenolate# and V"0#ÐO"3# "oxime# in the equatorial plane[ It can
been explained that the phenolate and oxime oxy! gen atoms have a high basicity and ensure sig! ni_cant back bonding of their O:V bond as revealed by the bond length data[ "e# The VÐN bond distance is 1[989"3#\ 1[945"4# and in complexes 0\ 1 and 2\ respectively\ 1[962"4# A # reported in which lie in the range "1[94Ð1[01 A 2¦ the VO hydrazone complexes ð8\ 09\ 04\ 11Ð17Ł[ # in complex The VÐN bond length "1[989"3# A 0 is slightly shorter than the corresponding one # in complex ðVOL0"OCH2#"CH2OH#Ł "1[008"5# A
Monooxovanadium"v# hydrazone complexes with hydrazone and hydroxamate
2590
# and angles "># for complex ðVOL1"bz#Ł CH1Cl1 "2# Table 4[ Selected bond distances "A V"0#ÐO"5# V"0#ÐO"4# V"0#ÐO"0# V"0#ÐO"1# V"0#ÐN"0# V"0#ÐO"3# O"0#ÐC"0# O"1#ÐC"8# O"2#ÐC"1# O"2#ÐC"7# O"3#ÐC"05#
0[483"3# 0[763"3# 0[776"3# 0[849"3# 1[962"4# 1[191"3# 0[221"5# 0[291"5# 0[267"6# 0[303"7# 0[135"5#
O"4#ÐN"2# N"0#ÐC"6# C"5#ÐC"6# C"8#ÐC"09# N"0#ÐN"1# N"1#ÐC"8# N"2#ÐC"05# C"05#ÐC"06# Cl"0#ÐC"12# Cl"1#ÐC"12# N"2# [[[ O"2a#
0[234"5# 0[183"6# 0[324"7# 0[379"7# 0[268"5# 0[201"6# 0[218"6# 0[384"7# 0[619"7# 0[623"7# 1[707"5#
O"5#ÐV"0#ÐO"4# O"5#ÐV"0#ÐO"0# O"5#ÐV"0#ÐO"1# O"5#ÐV"0#ÐN"0# O"5#ÐV"0#ÐO"3# O"4#ÐV"0#ÐO"0# O"4#ÐV"0#ÐO"1# O"4#ÐV"0#ÐN"0# O"4#ÐV"0#ÐO"3# O"0#ÐV"0#ÐO"1# O"0#ÐV"0#ÐN"0# O"0#ÐV"0#ÐO"3# O"1#ÐV"0#ÐN"0# O"1#ÐV"0#ÐO"3# N"0#ÐV"0#ÐO"3# N"1#ÐN"0#ÐV"0# C"8#ÐN"1#ÐN"0# C"05#ÐN"2#ÐO"4# O"0#ÐC"0#ÐC"5# C"11#ÐC"06#ÐC"05# C"07#ÐC"06#ÐC"05# C"0#ÐO"0#ÐV"0#
83[7"1# 88[7"1# 87[7"1# 88[3"1# 069[4"1# 090[1"1# 84[1"1# 052[8"1# 64[7"1# 043[9"1# 73[9"1# 72[3"1# 64[0"1# 70[1"1# 78[7"1# 005[5"3# 097[8"4# 004[8"3# 011[7"4# 007[0"4# 011[9"5# 022[5"2#
O"0#ÐC"0#ÐC"1# C"2#ÐC"1#ÐO"2# O"2#ÐC"1#ÐC"0# C"4#ÐC"5#ÐC"6# C"0#ÐC"5#ÐC"6# N"0#ÐC"6#ÐC"5# O"1#ÐC"8#ÐN"1# O"1#ÐC"8#ÐC"09# N"1#ÐC"8#ÐC"09# C"04#ÐC"09#ÐC"8# C"00#ÐC"09#ÐC"8# O"3#ÐC"05#ÐN"2# O"3#ÐC"05#ÐC"06# N"2#ÐC"05#ÐC"06# C"6#ÐN"0#ÐV"0# C"8#ÐO"1#ÐV"0# C"1#ÐO"2#ÐC"7# C"05#ÐO "3#ÐV"0# N"2#ÐO"4#ÐV"0# C"6#ÐN"0#ÐN"1# Cl"0#ÐC"12#ÐCl"1# N"2#ÐH"13# [[[ O"2a#
008[0"4# 013[8"5# 002[8"4# 008[7"5# 019[2"4# 014[9"4# 010[8"5# 007[8"4# 008[1"4# 010[3"5# 019[9"5# 007[4"4# 011[0"5# 008[1"4# 017[2"3# 006[4"3# 007[1"4# 009[1"3# 008[2"2# 004[9"4# 001[3"3# 040[8
Symmetry code] a\ !x\ !y\ !z[
ð17Ł[ It means that the presence of hydroxamate ligand in complex 0 results in the di}erence of VÐ N bond lengths between these two complexes[ "f # The hydrazone ligand in all four title complexes\ except the methanol group in complexes 2 and 3\ constitute a good plane with mean derivation of in complexes 0\ 1\ 9[921\ 9[908\ 9[909 and 9[962 A 2 and 3\ owing to the existence of delocalized p bond in hydrazone ligand[ "g# The NÐN bond distance in salicylhydroxamate or benzohydroxamate ligand is 0[393"4#\ 0[394"6#\ in complexes 0\ 1\ 2 and 0[268"5# and 0[277"4# A 3\ respectively\ which agree well with the NÐN # observed in the bond distances "0[27Ð0[30 A 2¦ known VO hydrazone complexes ð8\ 09\ 04\ 11Ð 17Ł[ The _rst four common structural features men! tioned above have also been observed in the two vanadium hydroxamate complexes reported by our group ð18Ł[ For the _rst time the salicylhydroxamate ligand
"Hshi#−0 is coordinated to oxovanadium"V# in a monoanion form of the type "O½O−# in complex 0[ In all known VO2¦ salicylhydroxamate complexes\ the salicylhydroxamate ligand is a dianion ð4Ł or tri! anion ð06Ł[ It is interesting to note that there is no intramolecular hydrogen bond between the oxygen atom of the pendant phenol and the hydroxamate nitrogen in complex 0\ although this kind of the hydro! gen bond has been found in complex ðVO"HSHED# "shi#Ł ð4Ł[ In complex 0\ there are two kinds of inter! molecular hydrogen bonds between the pendant O"4#Ð H group in the hydroxamate ligand and the nitrogen atom N"1a# in the hydrazone ligand of a neighbouring molecule and between vanadyl oxygen atom O"5# and N"2b#ÐH group in the hydroxamate ligand of another neighbouring molecule\ as given in Table 2[ In complex 1\ the bond length of V"0#ÐO"3# is \ somewhat shorter than the average 0[744"3# A # ð05Ł[ observed in the complex VOCl"bz#1 "0[891 A In complex 0\ the _ve!membered chelate ring of O"1#\ C"7#\ N"1#\ N"0#\ V"0# and the six!membered chelate ring of O"0#\ C"0#\ C"5#\ C"6#\ N"0#\ V"0# for!
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Shan Gao et al[
Fig[ 1[ Molecular structure of complex 0 showing the atom numbering and 29) probability displacement ellipsoids
Fig[ 2[ Molecular structure of complex 1 showing the atom numbering and 29) probability displacement ellipsoids
Monooxovanadium"v# hydrazone complexes with hydrazone and hydroxamate
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Fig[ 3[ Molecular structure of complex 2 showing the atom numbering and 29) probability displacement ellipsoids
med by the tridendate hydrazone ligand are planar and 9[946 A \ respec! with mean deviations of 9[939 A tively[ However\ in complex 1 the _ve!membered che! late ring is a good plane with a mean deviation of \ but the six!membered chelate ring is not 9[995 A planar[ The dihedral angle of two benzene rings of the hydrazone ligand is 10[1> in 0 and 8[1> in 1[ The dihedral angle between the hydroxamate ligand and the tridentate hydrazone ligand is 74[3> in 0 and 71[3> in 1[ In complex 2\ the atoms V"0#\ N"0#\ N"1#\ C"8#\ O"1# constitute an excellent plane with a mean devi! and the atoms V"0#\ O"3#\ C"05#\ ation of 9[994 A N"2#\ O"4# also constitute a good plane with a mean [ deviation of 9[917 A As illustrated in Table 4 and Fig[ 4\ two ðVO"L#"bz#Ł units related by a center of symmetry in complex 2 are joined by the two intermolecular hydrogen bonds N"2#ÐH"13# [[[ O"2a# and N"2a#ÐH"13a# [[[ O"2# "sym! metry code] a\ !x\ !y\ !z#[ Description of the structure of complex ðVOL1 "OCH2#"CH2OH#Ł CH2OH "3# The selected bond lengths and angles for complex 3 are listed in Table 5[ As shown in Fig[ 5\ the complex 3\ VOL1"OCH2#"CH2OH#ŁCH2OH\ has a distorted octahedral VO2¦ species with VO"ONO#"O#"O# type[ The atoms O"0#\ O"1#\ N"0# from the dinegative tri! dentate hydrazone ligand and atom O"3# from a methoxide ion de_ne a basal plane with small mean #[ The vanadium atom deviates by deviation "9[908 A from the equatorial plane towards the oxo 9[213 A
Fig[ 4[ Packing diagram of complex 2 showing H!bonding as broken lines
oxygen atom[ The oxo oxygen atom O"5# and the oxygen atom O"4# of the methanol molecule occupy the apical positions with a trans angle of 062[78"0#>\ the bond distances of the vanadyl V1O"5# and the and 1[235"3# A \ V"0#ÐO"4# "methanol# are 0[466"3# A respectively\ due to the structural trans e}ect[ The structural trans e}ect in the complexes with VO"ONO#"O#"O# type\ such as in complex 3 and VO"sal!L!ala# "OCH2#"CH2OH# ð24Ł\ is stronger than that in the ones with VO"ONO#"OO# type[ # in complex The vanadyl V1O distance "0[466"3# A ðVOL1"OCH2#"CH2OH#Ł CH2OH is shorter than that in complex ðVOL1"bz#Ł=CH1Cl1\ but is in the accept!
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Shan Gao et al[ # and angles "># for complex ðVOL1"OCH2# Table 5[ Selected bond distances "A "CH2OH#ŁCH2OH "3# V"0#ÐO"5# V"0#ÐO"3# V"0#ÐO"0# V"0#ÐO"1# V"0#ÐN"0# V"0#ÐO"4# O"0#ÐC"0# O"1#ÐC"8# O"2#ÐC"1#
0[466"3# 0[658"2# 0[739"2# 0[855"2# 1[098"3# 1[235"2# 0[225"4# 0[175"4# 0[259"4#
O"2#ÐC"7# O"3#ÐC"05# O"4#ÐC"06# O"6#ÐC"07# N"0#ÐC"6# N"0#ÐN"1# N"1#ÐC"8# O"6#[[[ N"1# O"4#[[[ O"6a#
0[321"4# 0[399"5# 0[289"6# 0[288"6# 0[171"4# 0[277"4# 0[297"5# 1[683"4# 1[569"4#
O"5#ÐV"0#ÐO"3# O"5#ÐV"0#ÐO"0# O"5#ÐV"0#ÐO"1# O"5#ÐV"0#ÐN"0# O"3#ÐV"0#ÐO"0# O"3#ÐV"0#ÐO"1# O"3#ÐV"0#ÐN"0# O"0#ÐV"0#ÐO"1# O"0#ÐV"0#ÐN"0# O"1#ÐV"0#ÐN"0# O"4#ÐV"0#ÐO"5# O"4#ÐV"0#ÐN"0# O"4#ÐV"0#ÐO"0# O"4#ÐV"0#ÐO"3# O"4#ÐV"0#ÐO"1#
093[1"1# 090[9"1# 85[4"1# 85[0"1# 092[1"0# 80[6"0# 045[5"1# 042[3"0# 73[9"0# 63[1"0# 062[8"0# 67[6"0# 70[6"0# 79[3"0# 68[1"0#
O"2#ÐC"1#ÐC"2# O"2#ÐC"1#ÐC"0# N"0#ÐC"6#ÐC"5# O"1#ÐC"8#ÐC"09# C"1#ÐO"2#ÐC"7# N"1#ÐC"8#ÐC"09# C"6#ÐN"0#ÐN"1# C"8#ÐN"1#ÐN"0# O"0#ÐC"0#ÐC"1# O"0#ÐC"0#ÐC"5# O"1#ÐC"8#ÐN"1# C"06#ÐO"4#ÐV"0# O"6#ÐH"19# [[[ N"1# O"4#ÐH"08# [[[ O"6a#
013[3"3# 004[4"3# 013[9"3# 007[9"3# 005[8"3# 007[7"3# 005[1"2# 097[3"2# 008[2"3# 010[3"3# 012[1"3# 021[8"2# 059[5 066[0
Symmetry code] a\ 9[4¦x\ −9[4!y\ z[
Fig[ 5[ Molecular structure of complex 3 showing the atom numbering and 29) probability displacement ellipsoids
observed for VO2¦ able range of 0[44Ð0[59 A complexes[ The VÐO"carbonyl# bond lying trans to \ which V1O in complex 3 has a distance 1[235"2# A # in is longer than the corresponding bond "1[191"3# A complex 2[ In complex 3\ there are intramolecular hydrogen bonds between the OH group of the uncoordinated CH2OH and the nitrogen atom of the hydrazone ligand and intermolecular hydrogen bonds between
the OH group of the coordinated CH2OH and the oxygen atom of the uncoordinated CH2OH in the neighbouring molecule\ shown in Fig[ 6 and Table 5[
Supplementary material The atomic coordinates for non!hydrogen atoms and hydrogen atoms\ anisotropic thermal parameters\
Monooxovanadium"v# hydrazone complexes with hydrazone and hydroxamate
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Fig[ 6[ Packing diagram of complex 3 showing H!bonding as broken lines
and full bond distances and angles have been deposited at the Cambridge Crystallographic Data Centre "CCDC#[ Any request to the CCDC for this material should quote the reference numbers 090211\ 090212\ 090213 and 090214 for the title complexes 0\ 1\ 2 and 3[ Acknowled`ements*The authors thank the _nancial support of the Natural Science Foundation of Fujian Province of China[ The authors thank associated professor Yu Zheng for the IR and Raman measurements and her valuable dis! cussion[
REFERENCES 0[ Rehder\ D[\ An`ew[ Chem[ Int[ Ed[ En`l[\ 0880\ 29\ 037[ 1[ Butler\ A[ and Walker\ J[ V[\ Chem[ Rev[\ 0882\ 82\ 0826[ 2[ Messerschmidt\ A[ and Wever\ R[\ Proc[ Natl[ Acad[ Sci[\ USA\ 0885\ 82\ 281[ 3[ Kehl\ H[ Ed[\ Chemistry + Biolo`y of Hydroxamic Acids\ S[ Karger] New York\ 0871[ 4[ Cornman\ C[ R[\ Colpas\ G[ J[\ Hoeschele\ J[ D[\ Kampf\ J[ and Pecoraro\ V[ L[\ J[ Am[ Chem[ Soc[\ 0881\ 003\ 8814[ 5[ Kiss\ T[\ Buglyo\ P[\ Micera\ G[\ Dess(\ A[ and Sanna\ D[\ J[ Chem[ Soc[\ Dalton Trans[\ 0882\ 0738[ 6[ Khan\ M[ I[\ Lee\ Y[!S[\ O|connor\ C[ J[\ Haush! alter\ R[ C[ and Zubieta\ J[\ Inor`[ Chem[\ 0883\ 22\ 2744[ 7[ Wang\ X[\ Zhang\ X[!M[ and Liu\ H[!X[\ Inor`[ Chim[ Acta\ 0883\ 112\ 082[ 8[ Chakravarty\ J[\ Dutta\ S[\ Dey\ A[ and Chak! ravorty\ A[\ J[ Chem[ Soc[\ Dalton Trans[\ 0883\ 446[ 09[ Ludwig\ E[\ Hefele\ H[\ Friedrich\ A[\ Kallies\ B[\ Schilde\ U[\ Uhlemann\ E[ and Hahn\ E[\ Z[ Anor`[ All`[ Chem[\ 0884\ 510\ 377[ 00[ Fulwood\ R[\ Schmidt\ H[ and Rehder\ D[\ J[ Chem[ Soc[\ Chem[ Commun[\ 0884\ 0332[
01[ Cavaco\ I[\ Pessoa\ J[ C[\ Duarte\ M[ T[\ Henriques\ R[ T[\ Matias P[ M[ and Gillard\ R[ D[\ J[ Chem[ Soc[\ Dalton Trans[\ 0885\ 0878[ 02[ Hamstra\ B[ J[\ Houseman\ A[ L[ P[\ Colpas\ G[ J[\ Kampf\ J[ W[\ LoBrutto\ R[\ Frasch\ W[ D[ and Pecoraro\ V[ L[\ Inor`[ Chem[\ 0886\ 25\ 3755[ 03[ Plass\ W[\ Z[ Anor`[ All`[ Chem[\ 0886\ 512\ 350[ 04[ Liu\ S[!X[ and Gao\ S[\ Polyhedron\ 0887\ 06\ 70[ 05[ Fisher\ D[ C[\ Barclay!Peet\ S[ J[\ Balfe\ C[ A[ and Raymond\ K[ N[\ Inor`[ Chem[\ 0878\ 17\ 3288[ 06[ Pecoraro\ V[ L[\ Inor`[ Chim[ Acta\ 0878\ 044\ 060[ 07[ Gibney\ B[ R[\ Stemmler\ A[ J[\ Pilotek\ S[\ Kampf\ J[ W[ and Pecoraro\ V[ L[\ Inor`[ Chem[\ 0882\ 21\ 5997[ 08[ Petrovic\ A[ F[\ Ribar\ B[\ Petrovic\ D[ M[\ Leovac\ V[ M[ and Gerbeleu\ N[ V[\ J[ Coord[ Chem[\ 0871\ 00\ 128[ 19[ Leovac\ V[ M[ and Petrovic\ A[ F[\ Transition Met[ Chem[\ 0872\ 7\ 226[ 10[ Zhang\ X[!M[\ You\ X[!Z[ and Wang\ X[\ Poly! hedron\ 0885\ 04\ 0682[ 11[ Diamantis\ A[ A[\ Frederiksen\ J[ M[\ Salam\ M[ A[\ Snow\ M[ R[ and Tiekink\ E[ R[ T[\ Aust[ J[ Chem[\ 0875\ 28\ 0970[ 12[ Yan\ S[!P[\ Wang\ G[!L[\ Wang\ H[!G[ and Yao\ X[!K[\ Chinese J[ Struct[ Chem[\ 0881\ 00\ 36[ 13[ Wang\ W[\ Wang\ X[\ Liu\ H[!X[ and Tan\ M[! Y[\ J[ Coord[ Chem[\ 0884\ 25\ 38[ 14[ Wang\ W[\ Zeng\ F[!L[\ Wang\ X[ and Tan\ M[! Y[\ Polyhedron\ 0885\ 04\ 0588[ 15[ Hefele\ H[\ Ludwig\ E[\ Schilde\ U[ and Uhle! mann\ E[\ Z[ Kristallo`r[\ 0885\ 100\ 544[ 16[ Palacios\ M[ S[\ Rocio\ M[ J[\ Dominguez\ S[\ Gili\ P[\ Ruiz!Perez\ C[\ Rodriguez!Romero\ F[ V[ and Dance\ J[!M[\ Polyhedron\ 0886\ 05\ 0032[ 17[ Bansse\ W[\ Ludwig\ E[\ Uhlemann\ E[\ Weller\ F[\ Dehnicke\ K[ and Herrmann\ W[\ Z[ Anor`[ All`[ Chem[\ 0881\ 502\ 25[ 18[ Liu\ S[!X[ and Gao\ S[\ to be published in Inor`[ Chim[ Acta[ 29[ Rowe\ R[ and Jones\ M[ M[\ Inor`[ Synth[\ 0846\ 4\ 002[ 20[ Gale\ G[ R[\ J[ Med[ Chem[\ 0857\ 00\ 080[
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21[ Nakamota\ K[\ Infrared and Raman Spectra of Inorganic and Coordination Compounds\ 3th edn[\ John Willy + Sons\ New York\ 0875[ 22[ Yang\ P[ and Li\ Q[!S[\ Chinese J[ Struct[ Chem[\ 0885\ 04\ 052[
23[ Asgedom\ G[\ Sreedhara\ A[ and Rao\ C[ P[\ Poly! hedron\ 0884\ 03\ 0762[ 24[ Nakajima\ K[\ Kojima\ M[\ Toriumi\ K[\ Saito\ K[ and Fujita\ J[\ Bull[ Chem[ Soc[ Jpn[\ 0878\ 51\ 659[
Pergamon PII] S9166Ð4276"87#99043Ð4
Polyhedron Vol[ 06\ No[ 19\ pp[ 2484Ð2595\ 0887 Þ 0887 Elsevier Science Ltd All rights reserved[ Printed in Great Britain 9166Ð4276:87 ,08[99¦9[99
Syntheses and characterization of four novel monooxovanadium"v# hydrazone complexes with hydroxamate or alkoxide ligand Shan Gao\ Zhi!Qiang Weng and Shi!Xiong Liu Dept[ of Chem[\ Fuzhou University\ Fuzhou 249991\ P[ R[ China "Received 2 December 0886^ accepted 5 April 0887# Abstract*Four novel monooxovanadium"V# hydrazone complexes\ ðVOL0"Hshi#Ł "0#\ ðVOL0"bz#Ł "1#\ ðVOL1"bz#Ł=CH1Cl1 "2#\ and ðVOL1"OCH2#"CH2OH#Ł=CH2OH "3# "H1L0 salicylaldehyde benzoylhydrazone\ H1L1 o!vanillin benzoylhydrazone\ H1shi salicylhydroxamic acid\ Hbz benzohydroxamic acid#\ were pre! pared and characterized by IR\ Raman\ UV\ 0H NMR spectra\ cyclic voltammetry measurements and X!ray di}raction[ The geometry around the vanadium atoms is a distorted VO"ONO#"OO# octahedron in complexes 0\ 1 and 2\ while the geometry is a distorted VO"ONO#"O#"O# octahedron in 3[ The V1O bond distance is for complexes 0\ 1\ 2 and 3\ respectively[ In complexes 0\ 1 and 2\ 0[463"3#\ 0[482"4#\ 0[483"3# and 0[466"3# A the O\ N\ O atoms of a tridentate hydrazone ligand and one oxime oxygen atom of a bidentate hydroxamate ligand are coordinated to the vanadium"V# atom\ forming an equatorial plane[ In complexes 0\ 1 and 2\ the axial position trans to the oxo group is occupied by the carbonyl oxygen atom of the hydroxamate ligand\ but not by the oxime oxygen atom[ The bond distances in the equatorial plane in the title complexes follow the order] alkoxide oxygen³phenoxide oxygen\ oxime oxygen³enolic oxygen³imine nitrogen[ The complexes 0\ 1 and 2 represent the _rst structural examples of vanadium complexes containing both hydrazone and hyd! roxamate ligands[ Þ 0887 Elsevier Science Ltd[ All rights reserved Keywords] monoxovanadium"V# complexes^ hydrazone complexes^ hydroxamate complexes^ crystal structures^ spectroscopic properties[ ———————————————————————————————————————————————
Knowledge of the biological role of vanadium as a trace element has considerably increased over the past decade ð0\ 1Ł[ A vanadium enzyme has been described which exhibits histidine!nitrogen coordination to vanadium ð2Ł[ The active sites of some biological enzymes include the hydroxamic acids ð3Ł[ Many small biomolecules such as hydroxy! or mercap! tocarboxylates\ amino acids\ hydroxamates\ hydra! zones\ phosphates\ phosphonates\ catechol derivatives\ etc[ are able to bind this element rather strongly in both the ¦3 and ¦4 oxidation states ð4Ð 04Ł[ However\ only a few structures of the simplest vanadium complexes with hydroxamate ligands have been studied ð4\ 05Ð07Ł[ Up to now\ only a few oxov! anadium hydrazone complexes have been reported[ These hydrazone complexes are only limited to dioxovanadium"V# complexes with VO1"ONO# coor!
Author to whom correspondence should be addressed[
dination ð7\ 08Ð10Ł\ and to monooxovanadium"V# complexes with square pyramidal VO"ONO#"O# coor! dination ð09\ 11Ð16Ł and octahedral "VO"ONO#"O#"O# ð17Ł or VO"ONO#"ON# ð8\ 04Ł coordination[ The relationships between structure\ spectroscopy\ and reactivity must be elucidated in order to under! stand fully the role of vanadium in biological systems[ We have undertaken the syntheses and charac! terization of some vanadium compounds containing tridentate ligand with VO"ONO#"ON# or VO"ONO#"OO# coordination ð04\ 18Ł[ Herein we report four monooxovanadium"V# hydrazone com! plexes with the hydroxamate or alkoxide ligand\ ðVOL0"Hshi#Ł "0#\ ðVOL0"bz#Ł "1#\ ðVOL1"bz#Ł=CH1Cl1 "2#\ and ðVOL1"OCH2#"CH2OH#Ł=CH2OH "3# "H1L0 salicylaldehyde benzoylhydrazone\ H1L1 o! vanillin benzoylhydrazone\ H1shi salicylhydroxamic acid\ Hbz benzohydroxamic acid#[ To the best of our knowledge\ the complexes 0\ 1\ and 2 are the _rst examples of vanadium hydrazone complexes with VO"ONO#"OO# coordination[
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Shan Gao et al[ EXPERIMENTAL
Materials The materials VO"acac#1 "acac acetylacetonate#\ Hbz and H1shi\ were synthesized according to refer! ences ð29\ 20Ł\ respectively[ The ligand H1L0 was pre! pared by condensing salicylaldehyde with equimolor benzoylhydrazine in ethanol[ The ligand H1L1 was synthesized by condensing o!vanillin with equimolor benzoylhydrazine in ethanol[ Analytically pure dichloromethane was distilled over calcium hydride before use[ All other analytical grade chemicals and solvents were purchased commercially and used with! out further puri_cation[
Synthesis of ðVOL0 "Hshi#Ł "0# ðVO"acac#1Ł "9[152 g\ 0[99 mmol# dissolved in 09 cm2 methanol was added dropwise to a methanol solution containing 9[139 g "0[99 mmol# of H1L0 with stirring\ and then the mixture was heated at re~ux with stirring for 0 h and cooled to room temperature[ 09 cm2 of mixed solution of methanol and salicylhydroxamic acid "0 mmol# was slowly added to the above red! black solution[ The reaction mixture was stirred for 29 min[ and _ltered[ Then deep red solid was dissolved in the dichloromethane and _ltered[ The deep red crystals of the complex 0 were obtained by slow di}usion of hexane into the _ltrate for several days and collected under vacuum over P3O09[
0
Synthesis of ðVOL "bz#Ł "1# The synthesis of complex ðVOL0"bz#Ł "1# was anal! ogous to that of complex 0\ only except that sali! cylhydroxamic acid was replaced by benzohydroxamic acid[ The deep red crystals of the complex 1 were formed upon slow evaporation of the _ltrate for several days and collected under vacuum over P3O09[
Synthesis of ðVO"L1#"bz#Ł=CH1Cl1 "2# A 04 cm2 CH2OH solution of VO"acac#1 "9[152 g\ 0[99 mmol# was added dropwise to a 04 cm2 CH2OH solution of H1L1 "0[99 mmol#[ The mixture was re~uxed with stirring for 0[4 h\ cooled to room tem! perature[ A 09 cm2 solution of benzohydroxamic acid "0[99 mmol# in CH2OH was added to the above dark red solution[ The mixture was stirred for 29 min[ and _ltered[ The red brown solid was dried under vacuum over P3O09 for 1 days\ dissolved in the dichlo! romethane and _ltered[ The deep red crystals of the complex 2 were isolated by slow di}usion of hexane into the above _ltrate for several days and collected under vacuum over P3O09[
Synthesis of ðVO"L1#"OCH2#"CH2OH#Ł=CH2OH "3# To H1L1 "0[99 mmol# dissolved in 04 cm2 CH2OH was added VO"acac#1 "9[152 g\ 0[99 mmol# in 04 cm2 CH2OH[ The mixture was re~uxed with stirring for 0 h\ cooled to room temperature and _ltered[ The deep red crystals of the complex 3 were obtained by slow evaporation of the deep red _ltrate at room tem! perature in a few days\ and then collected under vac! uum over P3O09[ Physical measurements IR spectra and Raman spectra were measured on a Nicolet Magna 649 Fourier transform IR spec! trometer and a Nicolet Raman 809 Fourier transform laser!Raman spectrometer\ respectively[ UV!vis spec! tra were obtained on a Perkin!Elmer lambda 8 UV:vis:near!IR spectrometer in CH1Cl1 solution and in the 299Ð0999 mm range[ 0H NMR spectra were collected on a Varian FT!79A spectrometer in CDCl2\ using TMS as internal standard[ Electrochemical measurements were undertaken on a BAS 099 A elec! trochemical analyzer on CH1Cl1 solution "0 mM com! plex\ 9[0 M "Et3N#ClO3#[ A three!electrode system was composed of a platinum working electrode\ a plati! num wire auxiliary electrode\ and a Ag:AgCl reference electrode[ X!ray structure determination X!ray di}raction data were recorded on a Rigaku AFC4R di}ractometer with graphite!mon! #\ the ochromated MoÐKa radiation "l 9[60958 A scan mode being v!1u[ Cell dimensions were re_ned using 14 re~ections in the ranges 19³1u³29>[ The di}raction data were corrected for Lorentz e}ect and polarization e}ect for the title complexes[ The crys! tallographic data are given in Table 0[ The structures were solved by direct methods and re_ned by a full!matrix least!squares procedure[ All non!hydrogen atoms were re_ned with anisotropic thermal parameters[ All hydrogen atoms were located by di}erence Fourier map or HYDROGEN program and added to the structure factor calculation\ but their positions were not re_ned[ RESULT AND DISCUSSION Spectroscopic studies Table 1 summarizes the IR and Raman spectra data of the free ligands and the title complexes[ A strong and broad band near 2027½2946 cm−0 is observed in IR spectra of the free ligands and assigned to the n"OH# absorption with hydrogen bond ð21\ 22Ł\ but disappeared in the four title complexes[ The bands at 2123 cm−0 in 0 and at 2047 cm−0 in 3 are due to the
Monooxovanadium"v# hydrazone complexes with hydrazone and hydroxamate
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Table 0[ Crystallographic data Complex
0
1
2
3
Formula Mr Crystal system Space group # a "A # b "A # c "A b "># 2# V "A Z F"999# Dcalc[ "g=cm−2# m Mo Ka "mm−0# Temperature "K# Shape Colour Crystal dimensions "mm# 1umax["># Collected data Unique data Observed data "I×2s"I9## No[ variables R Rw 2# Largest di}[ peak:hole"e:A Max[ shift
C10H05N2O5V 346[21 Monoclinic P10:n 01[747"2# 09[0393"8# 04[599"3# 83[06"1# 1918"0# 3 825 0[49 9[403 187 Prism Deep red 9[29×9[24×9[14 49[1 3990 2711 1062 170 9[940 9[952 9[27:−9[31 9[90
C10H05N2O4V 330[21 Monoclinic P10:a 01[188"4# 7[766"2# 07[760"4# 096[60"2# 0852"0# 3 893 0[38 9[414 187 Rhombus Deep red 9[34×9[34×9[19 49[1 2806 2622 1922 160 9[951 9[974 9[41:−9[28 9[90
C12H19Cl1N2O5V 445[16 Monoclinic P10:n 09[661"2# 19[347"2# 00[827"2# 009[04"1# 1369"0# 3 0025 0[49 9[537 185 Rhombus Deep red 9[29×9[29×9[19 49[9 3636 3386 1384 205 9[959 9[966 9[24:−9[23 9[90
C07H12N1O6V 329[22 Monoclinic P10:a 02[399"3# 6[302"1# 19[481"5# 86[62"1# 1916[9"8# 3 785 0[30 9[400 185 Prism Deep red 9[24×9[14×9[34 49[0 3960 2785 1152 143 9[942 9[957 9[28:−9[34 9[90
ArÐOH absorption in 0 and the coordinated CH2Ð OH absorption in 3\ respectively[ The medium strong bands at 855Ð879 cm−0 "IR# and at 859Ð868 cm−0 "Raman# in these title complexes are attributed to the typical V1O stretching frequencies\ falling within the range of 849Ð889 cm−0 reported for six!coordinated oxovanadium"V# complexes ð8\ 04Ð06\ 18Ł[ The very strong stretching vibrations of n "C1N# and n"C1O# are displaced to lower frequency ð16\ 22Ł\ and the strong n"CÐO# "phenolato oxygen# and the middle n"NÐH# absorption bands in the title complexes dis! play a shift to higher frequency with respect to the free ligands ð04\ 16\ 22Ł[ The new medium bands at 0144Ð0168 cm−0 "IR# and at 0140Ð0167 cm−0 "Raman# may be due to the enolic n"CÐO# absorption ð14\ 18Ł[ It shows that the hydrazone ligands in the title complexes are in a dianionic form of the type "−O½N½O−# and the two hydroxamate ligands are in a monoanionic form of the type "O½O−#[ The stretching vibrations of the VÐO bond and the VÐN bond have been observed at 388Ð244 cm−0 "far!IR#\ and 499Ð245 cm−0 "Raman# ð14Ł[ The 0H NMR spectra data of the free ligands and the title complexes are also shown in Table 1[ As expected\ OÐH and NÐH resonances of the free hydra! zone ligand are absent in the title complexes[ Broad NHÐOH resonances "d 7[66 and 7[89 ppm# of free salicylhydroxamic acid and benzohydroxamic acid
change into a singlet "d 7[87\ 7[85 and 7[82 ppm in 0\ 1 and 2\ respectively# ð22Ł\ indicating the coordination through their deprotonation of the hydroxyl group in the hydroxamate ligand[ In complex 0\ the peak at d 09[75 ppm is assigned to OÐH resonance bonding to aromatic ring of the salicylhydroximate ligand[ In complex 2\ the peak at 4[29 ppm is assigned to CH1 resonance to a dichlormethane molecule[ In complex 3\ the peaks at 4[20 ppm and 2[33Ð2[83 ppm are assigned to H and ÐCH2 resonances of the bonded methanol molecule[ These are agreement with the results of their single crystal analysis[ The LMCT transition "l 343\ 337\ 426 and 381 nm for 0\ 1\ 2 and 3\ respectively# is considered as a charge transfer from a p!orbital on the lone!pair of phenolato or oximate oxygen to the empty d!orbital of vanadium atom[ In contrast to other oxovanadium"V# hydra! zone complexes with 7!quinolinol co!ligand ð18\ 23Ł\ the absorption peaks of the visible region in the title complexes are obviously moved to the UV region[ The other strong bands "l 227\ 224\ 241 and 254 nm in 0\ 1\ 2 and 3\ respectively# are generally attributed to the intraligand absorption peaks ð23Ł[ The other LMCT band observed in the UV region "254 nm in 3\ 241 nm in 2# is due to alkoxo:enolic oxygen bound to vanadium"V# ð23Ł[ As illustrated in Fig[ 0\ there is a quasi!reversible redox behavior corresponding to VV:VIV couple in
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Table 1[ IR "Raman # and 0H NMR spectral data IR "Raman # "cm−0# Compound
n"OH#
Hbz H1Shi H1L0 H1L1 Complex 0
2189 2179 2154 2156 2220
2959 2027 2946 2986 2123
Complex 1
2335
Complex 2
2335
Complex 3
0
n"C1O# 0533 0546 0562 0569 ½0489 "½0435# ½0486 "½0446# ½0459 "½0471#
n"C1N#
n"CÐO#phenolic
n"CÐO#enolic
n"V1O#
n"VÐO#\n"VÐN#
857 "859# 879 "868# 855 "860# 864 "867#
350\244 "340\245# 346\251 "334\251# 387\346\317 "499\345\317# 371\317 "369\309#
CH1Cl1
ÐCH2"CH2OH#
789 0534 0532 0597 "0485# 0597 "0487# 0593 "0485# 0597 "0485#
0168 0168 0241 "0223# 0231 "0229# 0175 "0201# 0235 "0223#
0144 "0142# 0168 "0167# 0148 "0140# 0148 "0151#
NHÐOH
Phenyl
ÐOH"CH2OH#
ArÐOCH2
7[66 7[89
6[15½6[65 5[81½6[82 5[81½7[94 5[77½6[74 5[83½7[96 5[87½7[95 5[87½7[90 6[95½7[05
2047
n"NÐO#
803 "894#
H NMR "d ppm# ArÐOH
Hbz H1Shi H1L0 H1L1 Complex 0 Complex 1 Complex 2 Complex 3
09[37 00[92 8[82 09[75
NÐH
8[71 8[01
The bands at Raman spectra are given in parentheses[
7[87 7[85 7[82
2[82
4[20
2[72 2[85
ÐCH1NÐ
7[42 7[54 7[35 7[37 7[93 7[41
4[29 2[33½2[83
Shan Gao et al[
n"NH#
Monooxovanadium"v# hydrazone complexes with hydrazone and hydroxamate (a)
(b)
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dichloromethane solution in the title complexes[ Their redox potentials in complexes 0\ 1\ 2 and 3 are at E0:1 9[020 V\ 9[959 V\ 9[929 V and 9[227 V with respect to Ag:AgCl\ respectively[ The peak!to!peak separations "rEp of coupled peaks D:E# are 83 mV "0# and 89 mV "1# at a rate of 199 mV s−0[ The E0:1 value of the complex 0 is smaller of 60 mV than that of the complex 1 due to the di}erence between the bidentate hydroximate ligands[ It is noteworthy that the potentials of the VO2¦!VO1¦ couple in the com! plexes 2 and 3 are signi_cantly more positive than those observed for some VO2¦ complexes ð23Ł\ indi! cating that the complexes 2 and 3 are relatively unstable[ Description of the structures of complexes ðVOL0"Hshi#Ł "0#\ ðVOL0"bz#Ł "1# and ðVOL1"bz#Ł = CH1Cl1 "2# The selected bond lengths and angles in complexes 0\ 1 and 2 are listed in Table 2\ Table 3 and Table 4\ respectively[ The molecular structures of complexes 0\ 1 and 2 are shown in Fig[ 1\ Fig[ 2 and Fig[ 3[ There are seven common structural features in the complexes 0\ 1 and 2[
(c)
Fig[ 0[ Cyclic voltammogram of the title complexes 1\ 2 and 3 in dichloromethane "a# complex 1 "b# complex 2 "c# complex 3
"a# The coordination sphere around the vanadium atoms is a distorted octahedral con_guration with ðVVO"ONO#"OO#Ł type[ However\ most of vanadium atoms in the known vanadium hydra! zone complexes have a square pyramidal ðVVO"ONO#"O#Ł coordination ð09\ 11Ð16Ł\ only one complex has octahedral ðVVO"ONO#"O#"O#Ł coordination ð17Ł and two complexes have ðVVO"ONO#"ON#Ł coordination ð8\ 04Ł[ The title complexes 0\ 1 and 2 represent the _rst structural characterization of any vanadium hydrazone complex with VO"ONO#"OO# coordination[ "b# The equatorial plane is formed by the O\ N\ O atoms of the fully deprotonated tridentate hydra! zone ligand "L# and an oxime oxygen atom of the hydroxamate ligand[ The vanadium atom is \ 9[168 A and 9[160 A out the equatorial 9[160 A plane and toward the oxo oxygen atom in the complexes 0\ 1 and 2\ respectively[ "c# The atom lying trans to the oxo oxygen atom "Oo# is the carbonyl oxygen atom "Oc[# of the hydroximate ligand\ but not the oxime oxygen of the same ligand[ It may be related to the structural trans e}ect and the delocalized conjugated system between the V1O unit and the related group in hydroxamic acids[ The trans angle OoÐVÐOc[ is 060[3"1#>\ 061[7"1#> and 069[4"1#> in complexes 0\ 1 and 2\ respectively[ The vanadyl bond of V1O in complexes is 0[463"3#\ 0[482"4# and 0[483"3# A 0 1 and 2\ respectively[ The vanadyl bond length in complex 0 is at the shortest limit of normal V1O bond lengths\ although it is within the range # found in VO2¦ complexes ð04Ð07\ "0[46Ð0[50 A 11Ð17Ł[ In complex 1\ the V1O bond length and \ VÐO"2#"carbonyl# are 0[482"4# and 1[190"4# A
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Shan Gao et al[ # and angles "># for complex ðVOL0"Hshi#Ł "0# Table 2[ Selected bond distances "A V"0#ÐO"5# V"0#ÐO"0# V"0#ÐO"3# V"0#ÐO"1# V"0#ÐN"0# V"0#ÐO"2# O"0#ÐC"0# O"1#ÐC"7# O"4# [[[ N"1a#
0[463"3# 0[731"2# 0[759"2# 0[835"2# 1[989"3# 1[048"2# 0[217"5# 0[291"4# 1[613"4#
O"2#ÐC"04# O"3#ÐN"2# O"4#ÐC"06# N"0#ÐC"6# N"0#ÐN"1# N"1#ÐC"7# N"2#ÐC"04# C"04#ÐC"05# O"5# [[[ N"2b#
0[147"4# 0[261"4# 0[226"5# 0[175"5# 0[393"4# 0[175"5# 0[297"5# 0[369"5# 1[892"4#
O"5#ÐV"0#ÐO"0# O"5#ÐV"0#ÐO"3# O"5#ÐV"0#ÐO"1# O"5#ÐV"0#ÐN"0# O"5#ÐV"0#ÐO"2# O"0#ÐV"0#ÐO"3# O"0#ÐV"0#ÐO"1# O"0#ÐV"0#ÐN"0# O"0#ÐV"0#ÐO"2# O"3#ÐV"0#ÐO"1# O"4#ÐH "11# [[[ N"1a#
87[7"1# 83[7"1# 81[6"1# 096[8"1# 060[3"1# 090[9"0# 047[9"0# 73[0"0# 74[1"0# 85[6"0# 060[1
O"3#ÐV"0#ÐN"0# O"3#ÐV"0#ÐO"2# O"1#ÐV"0#ÐN"0# O"1#ÐV"0#ÐO"2# N"0#ÐV"0#ÐO"2# N"1#ÐC"7#ÐO"1# C"04#ÐO"2#ÐV"0# N"2#ÐO"3#ÐV"0# C"04#ÐN"2#ÐO"3# O"2#ÐC"04#ÐN"2# O"5# [[[ H"12b#ÐN"2b#
044[7"0# 65[8"0# 63[4"0# 75[9"0# 79[9"0# 011[6"4# 000[3"2# 006[0"1# 006[3"3# 005[7"3# 041[7
Symmetry code] a\ x\ 0¦y\ z^ b\ 9[4!x\ −9[4¦y\ 0[4!z[
# and angles "># for complex ðVOL0"bz#Ł "1# Table 3[ Selected bond distances "A V"0#ÐO"4# V"0#ÐO"0# V"0#ÐO"3# V"0#ÐO"1# V"0#ÐN"0# V"0#ÐO"2# O"0#ÐC"0#
0[482"4# 0[736"4# 0[744"3# 0[820"4# 1[945"4# 1[190"4# 0[214"6#
O"1#ÐC"7# O"2#ÐC"04# O"3#ÐN"2# N"0#ÐC"6# N"0#ÐN"1# N"1#ÐC"7# N"2#ÐC"04#
0[297"6# 0[131"6# 0[241"5# 0[174"7# 0[394"6# 0[177"7# 0[205"7#
O"4#ÐV"0#ÐO"0# O"4#ÐV"0#ÐO"3# O"4#ÐV"0#ÐO"1# O"4#ÐV"0#ÐN"0# O"4#ÐV"0#ÐO"2# O"0#ÐV"0#ÐO"3# O"0#ÐV"0#ÐO"1# O"0#ÐV"0#ÐN"0# O"0#ÐV"0#ÐO"2# O"3#ÐV"0#ÐO"1#
099[7"1# 86[6"1# 86[8"1# 86[9"1# 061[7"1# 88[2"1# 042[4"1# 72[7"1# 72[4"1# 85[5"1#
O"3#ÐV"0#ÐN"0# O"3#ÐV"0#ÐO"2# O"1#ÐV"0#ÐN"0# O"1#ÐV"0#ÐO"2# N"0#ÐV"0#ÐO"2# O"1#ÐC"7#ÐN"1# C"04#ÐO"2#ÐV"0# N"2#ÐO"3#ÐV"0# C"04#ÐN"2#ÐO"3# O"2#ÐC"04#ÐN"2#
053[0"1# 64[7"1# 64[3"1# 68[8"1# 78[1"1# 010[8"5# 009[6"3# 007[8"2# 006[9"4# 006[4"5#
which are longer than the corresponding bond distances of the complex 0[ It may be related to the di}erence between hydroxamate ligands in these two complexes[ "d# The four VÐO or VÐN bond distances in the equa! torial plane follow the order] alkoxide oxy! gen³phenoxide oxygen\ oxime oxygen³enolic oxygen³imine nitrogen[ The bond length of V"0#ÐO"1# "enolic oxygen# in complex 0 is ½9[0 A longer than that of the V"0#ÐO"0# "phenolate# and V"0#ÐO"3# "oxime# in the equatorial plane[ It can
been explained that the phenolate and oxime oxy! gen atoms have a high basicity and ensure sig! ni_cant back bonding of their O:V bond as revealed by the bond length data[ "e# The VÐN bond distance is 1[989"3#\ 1[945"4# and in complexes 0\ 1 and 2\ respectively\ 1[962"4# A # reported in which lie in the range "1[94Ð1[01 A 2¦ the VO hydrazone complexes ð8\ 09\ 04\ 11Ð17Ł[ # in complex The VÐN bond length "1[989"3# A 0 is slightly shorter than the corresponding one # in complex ðVOL0"OCH2#"CH2OH#Ł "1[008"5# A
Monooxovanadium"v# hydrazone complexes with hydrazone and hydroxamate
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# and angles "># for complex ðVOL1"bz#Ł CH1Cl1 "2# Table 4[ Selected bond distances "A V"0#ÐO"5# V"0#ÐO"4# V"0#ÐO"0# V"0#ÐO"1# V"0#ÐN"0# V"0#ÐO"3# O"0#ÐC"0# O"1#ÐC"8# O"2#ÐC"1# O"2#ÐC"7# O"3#ÐC"05#
0[483"3# 0[763"3# 0[776"3# 0[849"3# 1[962"4# 1[191"3# 0[221"5# 0[291"5# 0[267"6# 0[303"7# 0[135"5#
O"4#ÐN"2# N"0#ÐC"6# C"5#ÐC"6# C"8#ÐC"09# N"0#ÐN"1# N"1#ÐC"8# N"2#ÐC"05# C"05#ÐC"06# Cl"0#ÐC"12# Cl"1#ÐC"12# N"2# [[[ O"2a#
0[234"5# 0[183"6# 0[324"7# 0[379"7# 0[268"5# 0[201"6# 0[218"6# 0[384"7# 0[619"7# 0[623"7# 1[707"5#
O"5#ÐV"0#ÐO"4# O"5#ÐV"0#ÐO"0# O"5#ÐV"0#ÐO"1# O"5#ÐV"0#ÐN"0# O"5#ÐV"0#ÐO"3# O"4#ÐV"0#ÐO"0# O"4#ÐV"0#ÐO"1# O"4#ÐV"0#ÐN"0# O"4#ÐV"0#ÐO"3# O"0#ÐV"0#ÐO"1# O"0#ÐV"0#ÐN"0# O"0#ÐV"0#ÐO"3# O"1#ÐV"0#ÐN"0# O"1#ÐV"0#ÐO"3# N"0#ÐV"0#ÐO"3# N"1#ÐN"0#ÐV"0# C"8#ÐN"1#ÐN"0# C"05#ÐN"2#ÐO"4# O"0#ÐC"0#ÐC"5# C"11#ÐC"06#ÐC"05# C"07#ÐC"06#ÐC"05# C"0#ÐO"0#ÐV"0#
83[7"1# 88[7"1# 87[7"1# 88[3"1# 069[4"1# 090[1"1# 84[1"1# 052[8"1# 64[7"1# 043[9"1# 73[9"1# 72[3"1# 64[0"1# 70[1"1# 78[7"1# 005[5"3# 097[8"4# 004[8"3# 011[7"4# 007[0"4# 011[9"5# 022[5"2#
O"0#ÐC"0#ÐC"1# C"2#ÐC"1#ÐO"2# O"2#ÐC"1#ÐC"0# C"4#ÐC"5#ÐC"6# C"0#ÐC"5#ÐC"6# N"0#ÐC"6#ÐC"5# O"1#ÐC"8#ÐN"1# O"1#ÐC"8#ÐC"09# N"1#ÐC"8#ÐC"09# C"04#ÐC"09#ÐC"8# C"00#ÐC"09#ÐC"8# O"3#ÐC"05#ÐN"2# O"3#ÐC"05#ÐC"06# N"2#ÐC"05#ÐC"06# C"6#ÐN"0#ÐV"0# C"8#ÐO"1#ÐV"0# C"1#ÐO"2#ÐC"7# C"05#ÐO "3#ÐV"0# N"2#ÐO"4#ÐV"0# C"6#ÐN"0#ÐN"1# Cl"0#ÐC"12#ÐCl"1# N"2#ÐH"13# [[[ O"2a#
008[0"4# 013[8"5# 002[8"4# 008[7"5# 019[2"4# 014[9"4# 010[8"5# 007[8"4# 008[1"4# 010[3"5# 019[9"5# 007[4"4# 011[0"5# 008[1"4# 017[2"3# 006[4"3# 007[1"4# 009[1"3# 008[2"2# 004[9"4# 001[3"3# 040[8
Symmetry code] a\ !x\ !y\ !z[
ð17Ł[ It means that the presence of hydroxamate ligand in complex 0 results in the di}erence of VÐ N bond lengths between these two complexes[ "f # The hydrazone ligand in all four title complexes\ except the methanol group in complexes 2 and 3\ constitute a good plane with mean derivation of in complexes 0\ 1\ 9[921\ 9[908\ 9[909 and 9[962 A 2 and 3\ owing to the existence of delocalized p bond in hydrazone ligand[ "g# The NÐN bond distance in salicylhydroxamate or benzohydroxamate ligand is 0[393"4#\ 0[394"6#\ in complexes 0\ 1\ 2 and 0[268"5# and 0[277"4# A 3\ respectively\ which agree well with the NÐN # observed in the bond distances "0[27Ð0[30 A 2¦ known VO hydrazone complexes ð8\ 09\ 04\ 11Ð 17Ł[ The _rst four common structural features men! tioned above have also been observed in the two vanadium hydroxamate complexes reported by our group ð18Ł[ For the _rst time the salicylhydroxamate ligand
"Hshi#−0 is coordinated to oxovanadium"V# in a monoanion form of the type "O½O−# in complex 0[ In all known VO2¦ salicylhydroxamate complexes\ the salicylhydroxamate ligand is a dianion ð4Ł or tri! anion ð06Ł[ It is interesting to note that there is no intramolecular hydrogen bond between the oxygen atom of the pendant phenol and the hydroxamate nitrogen in complex 0\ although this kind of the hydro! gen bond has been found in complex ðVO"HSHED# "shi#Ł ð4Ł[ In complex 0\ there are two kinds of inter! molecular hydrogen bonds between the pendant O"4#Ð H group in the hydroxamate ligand and the nitrogen atom N"1a# in the hydrazone ligand of a neighbouring molecule and between vanadyl oxygen atom O"5# and N"2b#ÐH group in the hydroxamate ligand of another neighbouring molecule\ as given in Table 2[ In complex 1\ the bond length of V"0#ÐO"3# is \ somewhat shorter than the average 0[744"3# A # ð05Ł[ observed in the complex VOCl"bz#1 "0[891 A In complex 0\ the _ve!membered chelate ring of O"1#\ C"7#\ N"1#\ N"0#\ V"0# and the six!membered chelate ring of O"0#\ C"0#\ C"5#\ C"6#\ N"0#\ V"0# for!
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Shan Gao et al[
Fig[ 1[ Molecular structure of complex 0 showing the atom numbering and 29) probability displacement ellipsoids
Fig[ 2[ Molecular structure of complex 1 showing the atom numbering and 29) probability displacement ellipsoids
Monooxovanadium"v# hydrazone complexes with hydrazone and hydroxamate
2592
Fig[ 3[ Molecular structure of complex 2 showing the atom numbering and 29) probability displacement ellipsoids
med by the tridendate hydrazone ligand are planar and 9[946 A \ respec! with mean deviations of 9[939 A tively[ However\ in complex 1 the _ve!membered che! late ring is a good plane with a mean deviation of \ but the six!membered chelate ring is not 9[995 A planar[ The dihedral angle of two benzene rings of the hydrazone ligand is 10[1> in 0 and 8[1> in 1[ The dihedral angle between the hydroxamate ligand and the tridentate hydrazone ligand is 74[3> in 0 and 71[3> in 1[ In complex 2\ the atoms V"0#\ N"0#\ N"1#\ C"8#\ O"1# constitute an excellent plane with a mean devi! and the atoms V"0#\ O"3#\ C"05#\ ation of 9[994 A N"2#\ O"4# also constitute a good plane with a mean [ deviation of 9[917 A As illustrated in Table 4 and Fig[ 4\ two ðVO"L#"bz#Ł units related by a center of symmetry in complex 2 are joined by the two intermolecular hydrogen bonds N"2#ÐH"13# [[[ O"2a# and N"2a#ÐH"13a# [[[ O"2# "sym! metry code] a\ !x\ !y\ !z#[ Description of the structure of complex ðVOL1 "OCH2#"CH2OH#Ł CH2OH "3# The selected bond lengths and angles for complex 3 are listed in Table 5[ As shown in Fig[ 5\ the complex 3\ VOL1"OCH2#"CH2OH#ŁCH2OH\ has a distorted octahedral VO2¦ species with VO"ONO#"O#"O# type[ The atoms O"0#\ O"1#\ N"0# from the dinegative tri! dentate hydrazone ligand and atom O"3# from a methoxide ion de_ne a basal plane with small mean #[ The vanadium atom deviates by deviation "9[908 A from the equatorial plane towards the oxo 9[213 A
Fig[ 4[ Packing diagram of complex 2 showing H!bonding as broken lines
oxygen atom[ The oxo oxygen atom O"5# and the oxygen atom O"4# of the methanol molecule occupy the apical positions with a trans angle of 062[78"0#>\ the bond distances of the vanadyl V1O"5# and the and 1[235"3# A \ V"0#ÐO"4# "methanol# are 0[466"3# A respectively\ due to the structural trans e}ect[ The structural trans e}ect in the complexes with VO"ONO#"O#"O# type\ such as in complex 3 and VO"sal!L!ala# "OCH2#"CH2OH# ð24Ł\ is stronger than that in the ones with VO"ONO#"OO# type[ # in complex The vanadyl V1O distance "0[466"3# A ðVOL1"OCH2#"CH2OH#Ł CH2OH is shorter than that in complex ðVOL1"bz#Ł=CH1Cl1\ but is in the accept!
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Shan Gao et al[ # and angles "># for complex ðVOL1"OCH2# Table 5[ Selected bond distances "A "CH2OH#ŁCH2OH "3# V"0#ÐO"5# V"0#ÐO"3# V"0#ÐO"0# V"0#ÐO"1# V"0#ÐN"0# V"0#ÐO"4# O"0#ÐC"0# O"1#ÐC"8# O"2#ÐC"1#
0[466"3# 0[658"2# 0[739"2# 0[855"2# 1[098"3# 1[235"2# 0[225"4# 0[175"4# 0[259"4#
O"2#ÐC"7# O"3#ÐC"05# O"4#ÐC"06# O"6#ÐC"07# N"0#ÐC"6# N"0#ÐN"1# N"1#ÐC"8# O"6#[[[ N"1# O"4#[[[ O"6a#
0[321"4# 0[399"5# 0[289"6# 0[288"6# 0[171"4# 0[277"4# 0[297"5# 1[683"4# 1[569"4#
O"5#ÐV"0#ÐO"3# O"5#ÐV"0#ÐO"0# O"5#ÐV"0#ÐO"1# O"5#ÐV"0#ÐN"0# O"3#ÐV"0#ÐO"0# O"3#ÐV"0#ÐO"1# O"3#ÐV"0#ÐN"0# O"0#ÐV"0#ÐO"1# O"0#ÐV"0#ÐN"0# O"1#ÐV"0#ÐN"0# O"4#ÐV"0#ÐO"5# O"4#ÐV"0#ÐN"0# O"4#ÐV"0#ÐO"0# O"4#ÐV"0#ÐO"3# O"4#ÐV"0#ÐO"1#
093[1"1# 090[9"1# 85[4"1# 85[0"1# 092[1"0# 80[6"0# 045[5"1# 042[3"0# 73[9"0# 63[1"0# 062[8"0# 67[6"0# 70[6"0# 79[3"0# 68[1"0#
O"2#ÐC"1#ÐC"2# O"2#ÐC"1#ÐC"0# N"0#ÐC"6#ÐC"5# O"1#ÐC"8#ÐC"09# C"1#ÐO"2#ÐC"7# N"1#ÐC"8#ÐC"09# C"6#ÐN"0#ÐN"1# C"8#ÐN"1#ÐN"0# O"0#ÐC"0#ÐC"1# O"0#ÐC"0#ÐC"5# O"1#ÐC"8#ÐN"1# C"06#ÐO"4#ÐV"0# O"6#ÐH"19# [[[ N"1# O"4#ÐH"08# [[[ O"6a#
013[3"3# 004[4"3# 013[9"3# 007[9"3# 005[8"3# 007[7"3# 005[1"2# 097[3"2# 008[2"3# 010[3"3# 012[1"3# 021[8"2# 059[5 066[0
Symmetry code] a\ 9[4¦x\ −9[4!y\ z[
Fig[ 5[ Molecular structure of complex 3 showing the atom numbering and 29) probability displacement ellipsoids
observed for VO2¦ able range of 0[44Ð0[59 A complexes[ The VÐO"carbonyl# bond lying trans to \ which V1O in complex 3 has a distance 1[235"2# A # in is longer than the corresponding bond "1[191"3# A complex 2[ In complex 3\ there are intramolecular hydrogen bonds between the OH group of the uncoordinated CH2OH and the nitrogen atom of the hydrazone ligand and intermolecular hydrogen bonds between
the OH group of the coordinated CH2OH and the oxygen atom of the uncoordinated CH2OH in the neighbouring molecule\ shown in Fig[ 6 and Table 5[
Supplementary material The atomic coordinates for non!hydrogen atoms and hydrogen atoms\ anisotropic thermal parameters\
Monooxovanadium"v# hydrazone complexes with hydrazone and hydroxamate
2594
Fig[ 6[ Packing diagram of complex 3 showing H!bonding as broken lines
and full bond distances and angles have been deposited at the Cambridge Crystallographic Data Centre "CCDC#[ Any request to the CCDC for this material should quote the reference numbers 090211\ 090212\ 090213 and 090214 for the title complexes 0\ 1\ 2 and 3[ Acknowled`ements*The authors thank the _nancial support of the Natural Science Foundation of Fujian Province of China[ The authors thank associated professor Yu Zheng for the IR and Raman measurements and her valuable dis! cussion[
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