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Molecular complexes of 4-NH2-benzophenone with bismuth(III) halides and with iodine
S 8 arochlmica Acta. Vol. 35A. pp. 105 10 108 C Pcrgamon Press Ltd.. 1979. Printed in Great Brltam
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Molecular complexes of 4-NH,-benzophenone with bismuth(II1) halides and with iodine IDA
VEZZCSI, ALINE FRANCAZANOLIand GIORGIO F’EYRONEL lstituto di Chimica Generale e Inorganica, University of Modena,
MARIA
41100 Modena, Italy (Receiued21 January 1978). Abstract-The following solid complexes of CNHr-benzophenone (L) with bismuth (III) chloride. bromide and iodide and with iodine were prepared: BiC13.L (yellow), BiCl,.ZL (red), 3BiBr,.ZL (orange), BiBrx.2L (red). 2BiIs.3L (red). 1.L (yellow). 1.2L (orange). 1.3L (red). The iodine complexes are obtained from ethanolic solutions of BiIJ and the ligand. by precipitation with water or ligroin, the iodide ion being oxydized to iodine by the oxygen dissolved in the solvents. From an oxygen free hgroin-ethanolic solution only 2 BiI,.3L is obtained. The i.r. spectra of the solids show that in the yellow or orange BiX3 complexes the NH, group is involved into the coordination while in the red BiXa complexes and in the orange and red iodine complexes the v(NH) bands of the ligand remain unaltered. The carbonylic oxygen is not involved in the coordination. In DCM solution the red BiX, complexes and all the iodine complexes show a C.T. band at 440420 nm, the energy of which gives a linear plot versus the electron affinity of the three halogens. The electronic spectra of the solids show a C.T. band in the region 470-500 nm.
INTRODUCTION
In previous works we have prepared and investigated in the solid state and in solution the molecular complexes of antimony(II1) and bismuth(II1) chloride and bromide with pyrene [l, 21, of antimony(I11) chloride and bromide with benzophe%one and 4-R-benzophenones (R =Cl. Br. NH21 [3] and ofbismuth(III)chloride and bromide with benzophenone and CR-benzophenones (R =Cl. Br. Me) [4]. Benzophenone gives solid complexes with the halides of several other elements [5-73. The complexes of CNH,-benzophenone with bismuth(II1) chloride, bromide and iodide and with iodine have now been prepared and investigated in the solid state and in solution for a comparison with the corresponding antimony(II1) halide complexes.
EXPERIMENTAL The ligand was purified by recrystallization from petroleum ether. The bismuth trihalides (Hopkins and Williams) were dried on P20,. All the solvents were dehydrated and kent on metallic sodium. Dichloromethane (DCM) for sp&trophotometric measurements (Merck) was dehydrated with &Cl2 and fractionally distilled collecting the fraction distillina at 40°C. All the manipulations were done and all the reag&ts and vessels were kept in a dry box on P20s. The complexes were prepared as follows: BiCI, . (4NH*-Ph&O): by adding the solid ligand to a saturated solution of Bit& in DCM a microcrystalline yellow product precipitates. BiClj. 2(4-NH,-Ph,CO): a DCM solution saturated with both the reagents becomes deep red giving. after some days, a very thick red mud which, by washing it several times with ligroin or petroleum ether. is transformed into a red powder. Some time well shaped red crystals grow on the wall of the vessel. 3BiBr,.2(4-NH,-Ph,CO): the orange microcrystalline product is obtained by adding petroleum ether to a DCM solution containing an excess of BiBr, with respect to the
&and or by diluting a DCM solution saturated with both tmr=%ents BiBr, .2(4-NHs-PhrCO): by adding petroleum ether to a concentrated DCM solution of the reagents, containing a large excess of the ligand, a red mud is formed which, by washing it several times with ligroin, is transformed into a red powder. 1. (4NH*-PhrCO): by adding an equimolecular quantity of the soiid ligand to a solution of BiI, in ethanol the colour of the solution becomes deep yellow, and by adding water under strong stirring the crystalline needle-like yellow product precipitates. 1.2(4-NH,-PhsCO): the orange microcrystalline product precipitates by adding water under stirring to an ethanolic solution of BiI, containing an excess of the ligand. 1. 3(4-NH*-PhrCO): by adding ligroin to an ethanolic solution saturated with BiI, and the ligand the crystalline deep red product precipitates. ZBiI, . 3(4-NH2-Ph*CO): by adding oxygen free ligroin to an oxygenfree ethanolic solution saturated with BiI, and the ligand a red oil is formed which crystallizes, by standing in the mother solution, into a red powder. Ah the compounds are stable in air and soluble in several organic solvents. From an ethanolic solution of iodine and an excess of CNH,-Ph,CO by adding water only the free ligand precip itates and by adding ligroin only a change of colour is obtained. From a DCM solution of iodine and an excess of +NH,-Ph&O by adding cyclohexane a yellow product precipitates which becomes red and contains a large excess of the free ligand. The compounds were analysed (Table 1) by combustion for C, H, N and by titrating the halide ions in aqueous acidic solution by the Vohlard method. The electronic spectra were recorded on the solutions with a Beckman DK 1A spectrophotometer and on the solids in Nujol mulls on quartz plates with a Shimadzu MPS-SOL spectrophotometer and the i.r. spectra on the solids in KBr disks (4000-250 cm- ‘) with a Perkin-Elmer 521 spectrophotometer (Table 2). RESULTS
AND DISCUSSION
Two types of solid complexes, yellow-orange and red, are formed by 4-NH,-Ph,CO with bismuth(II1) chlor-
106
IDA
MARIAVEZZOSI,ALINEFRANCAZANOLIand GIORGIOPEYRONEL Table 1. Analytical data. found % (calcd. %)
BiClJ.(4-NH*-Ph&O) BiCI,.2(4-NH2-Ph,CO) 3BiBr,.2(4-NHt-Ph2CO) BiBrs.2(4-NH*-Ph,CO) 2BiIJ.3(4-NH,-Ph,CO) I.(4-NH2-Ph&O) 1.2(4-NH,-Ph2CO) 1.3(4-NH,-Ph,CO)
Colour
C
H
N
X
yellow red orange red red yellow orange red
29.12(30.43) 42.87(43.95) 18.32(17.94) 36.48(37.00) 26.3q26.42) 50.02(48.26) 59.2q59.88) 65.07(65.18)
2.16(2.14) 3.00(3.09) 1.12(1.32) 2.68(2.60) 2.02(1.86) 4.28(3.39) 4.1E44.22) 4.7q4.60)
2.28(2.73) 3.77(3.94) 1.67(1.61) 3.43(3.32) 2.18(2.37) 4.83(4.32) 5.18(5.37) 5.53(5.85)
20.68(20.75) 15.06(14.98) 40.97(41.32) 28.2q28.42) 38.9q39.15) 23.43(24.38) 18.09(17.69)
Table 2. Infrared (cm-‘) and electronic (nm) CT. bands of the ligand and its complexes
4-NH*-Ph&O BiCII.(4-NHt-PhzCO) BiCla.2(4-NH,-Ph,CO) 3BiBr,.2(4-NH*-Ph,COj BiBr3.2(4-NH2-Ph&O) 2BiI,.3(4-NHI-Ph2CO) 1.(4-NH2-Ph,CO) 1.2(4-NH,-Ph,CO) 1.3(4-NHz-Ph,CO) I2 +4-NH*-Ph,CO in DCM
v(NH)
v(CO)
3423m 3343ms 3225m 3430wb 3355w,sh 3105m,sh 3045msb 3415dmb 3312ms 3190wm 3405wmb 3310m 3180~ 2905m 3415wmb 3320ms 3197mw 3450m 335Oms 3205m
1630~s 1640s 1620s 1610s 1618s 1615s
3400ms 3316s 3204ms 3402ms 3320s 3208ms .
1625~s 1624~s
C.T. band
440 430,392 434 422 423 423 420
ide and bromide as with antimony(II1) chloride and bromide [3]. Only the red 2BiIa * 3(4-NHz-Ph2CO) complex could be isolated from oxygen free ethanolligroin solutions. Three iodine complexes are formed from Bi13 and the ligand in oxygen-containing solutions.
of two different complexes in solution. The red complexes BiCIB *2(4-NH,-Ph&O), BiBr, . 2(4-NH2-Ph2CO) and 2BiIJ. 3(4-NHz-PhzCO) give only one rather strong band at 440,434 and 422 nm, respectively, which remains unaltered even with a large excess of ten times of the ligand. The three iodine complexes obtained from
The i.r. v(C0) frequency of the ligand remains almost unaltered in the complexes, its variations (Tom + 10 to -20 cm-‘) being attributable to weak intermolecular interactions; a metal-ligand bonding through the carbonylic oxygen may therefore be excluded. The v(NH) bands of all the “red” halide complexes (Table 2 and Fig. 1) are well shaped and almost identical to those of the ligand while they are very deformed for the “yellow” or “orange” complexes. This indicates, as for the antimony(II1) chloride and bromide complexes [S]. that in the “yellow-orange” form the NH,-group is N-bonded to the bismuth halide while it is not involved in the formation of the solid red complexes. In DCM solution (3.10-%) 4-NH2-Ph2C0 shows two sharp bands at 313 and 238 nm which remain unaltered in the complexes. The yellow complex BiCIS *+I-NH*-Ph,CO) does not show any distinct C.T. band in the visible region, while the orange complex 3BiBr3. 2(4-NH,-Ph,CO) gives two C.T. maxima at 430 and 392 nm (Fig. 2), attributable to the existence
Bi13 give in DCM solution the same spectrum (Fig. 2)
showing unaltered the two strong ligand bands at 313 and 238 nm and a new C.T. band at 423 nm. The same C.T. band at 420 nm is given by the DCM solution of iodine (4*10-(M) and 4-NH2-Ph$O (1.6. 10e3@. A plot of the hv values of the C.T. bands of the red BiCI,. BiBr, and Bi13 complexes versus the electronic affinity (Eu) [8] of the halogens gives a straight line in agreement with the assumption [9] that the wavelength at the maximum of the C.T. band for a series of complexes increases with the increase in the electron affinities of the acceptor. The iodine compounds obtained from Bi13 do not show any i.r. v(NH:) or v(OH+) bands indicating a protonation from HI molecules formed by hydtolysis of Bi13, their v(NH) bands being identical to those of the ligand, and their electronic spectra in DCM solution are identical to that of the DCM solution of Iz and CNH,-Ph,CO. As these complexes are formed only in oxygen containing solutions an oxidation of the
Molecular complexes of CNH&enzophenone
: c
b
1
:
I
I
VG I
I
107
(410-430 run) in which appears the visible band of the iodine complexes with donors at a nitrogen atom [ 111. This band is shifted to 435-470 nm and at 490-510 nm for donors at an oxygen atom and for aromatic or ethylene hydrocarbons, respectively [ll]. Structures like CsHSN+ . CH31- [9] and (PyI)+I- or Py’I; [lo] have been proposed. The C.T. band at 420-423 nm seems therefore to indicate a N+I- interaction for the iodine (4-NH2Ph,CO) complexes in DCM solution. An ionic form is also supported by the molar conductivity of 2(4-NH2Ph$O)I(h=61 in 1.33.10m3 M and 73 in CL~.~O-~M methanol solution) for which a constitution in solution like @-NH,-Ph,CO);Imay be proposed. As in the solid state these complexes show i.r. v(NH) bands almost identical in position and intensity to those of the l&and, independently from their orange or red colour, while a N+I- interaction should substantially alter these bands, it is likely that in the solid state another type of coordination occur, in which the n-electrons of the aromatic ring are involved.
1
3500
3000 cm-'
Fig. 1. Infrared v(NH) and VfCH) bands of: (a) CNHZbenzophenone (4-NH,-PhrCO); (b) BiBr, .2(4-NH*-Ph,CO), red;(c) 3Biljra . 2(4-NH2-R&O), orange; (d) BfCls .2@&NH,-Ph,CO), red; (e) BiCl, . (4-NHa-PhrCO), yellow.
EO
3.0-
Fig. 3. Plot of the electron affinity En (eV) of chlorine (3.61) bromine (3.36) and iodine (3.06) [E] versus the C.T. band energies hv (eV) of the red complexes: BiCl, .2(4-NH2Ph,CO) (2.817), BiBr, .2(4-NH,-PhaCO) (2.856); 2BiI,. 3(4-NH2-Ph,CO) (2.930). Also the “red” complexes I 360
1
I 400
I
I 440 "Ill
#
I
I
460
Fig. 2. Electronic spectra in dichloromethane solution of: (a) 3BiBr,. 2(4-NH,-Ph,CO), orange; (b) BiBr, 2(4-NH2Ph,CO), red; (c) I,(4. 10e4 M)+4-NH,-PhrCO (1.6. 10m3 M);(d) 1.3(4-NH,-Ph,CO), red. iodide ion of BiI, by the oxygen dissolved in the solution must occur. Iodine gives with pyridine in n-heptane solution a C.T. band at 422 nm [lo], and at about 410 nm with triethylamine in n-heptane [ 111, in the spectral region
of the ligand with BiC13,
BiBr, and Bi13 show unaltered the v(NH) bands of the ligand in the solid state (Fig. 1) and have electronic spectra in DCM solution very similar to those of the iodine complexes (Fig. 2). The electronic spectra of the solids recorded in Nujol mull on quartz plate show for the three red complexes BiCl,.2(4-NH,-Ph,CO), BiBr3.2(4-NH2Ph,CO) and 1’3(4-NH1-Ph,CO) a very large C.T. band, the maximum of which lies in the region 470-500 nm. This confirms that in the solid state the red complexes have a coordination different than in solution, the position of the C.T. band indicating that in the solid state the aromatic rings of the ligand may be involved into the coordination.
108
IDA
MARIAVEZZOSI,ALINEFRANCAZANOLIand GIORGIOPEYRONEL
[5] B. P. Susz and P. CHALANDON, He/o. Chim. Acta 41, 1332 (1958). [6] R. C. PALL and S. L. CHADHA.J. Inorg. Nucl. Chem. 30. 1679 (1968). [7] V. BALZANIand L. MAGGI,Ann. Chimica 53.166 (1963). [8] F. A. COTTONand G. WILKINSON.Advanced Inorganic REFERENCES Chemistry, Wiley-Interscience. New York (1972). [9] L. J. ANDREWS and R. M. KEEFERMolecular Complexes G. PEYRONEL, I. M. VEZZ~U and S. BUFFAGNI,Inorg. in Organic Chemistry. pp. 24 and 137, Holden-Day. Chim. Acta 4,605 (1970). San Francisco (1964). G. B~MBIERI,G. PEYRONEL and I. M. VEZZOSI,Inorg. [lo] C. REID and R. S. MULLIKEN,J. Am. Chem. Sot. 76, Chim. Acta 6, 349 (1972). 3869 (1954). I. M. VEZZOSI,G. PEYRONEL and A. F. ZANOLI,Spectro[ 1l] R. S. MULLIKENand W. B. PERSON.Molecular Comchim. Acta 32A, 679 (1976). plexes. A Lecture and Reprint Volume, pp. 157-158. I. M. VEZZOSI. A. F. ZANOLI and G. PEYRONEL, John Wiley, New York (1969). Spectrochim. Acta 34A, 651 (1978).
Acknowledgements-This work was supported by a financial aid from the Consiglio Nationale delle Richerche (CNR) of Italy.
[l] [2] [3] [4]
0584-8539 79.02014105$02.00/0
Molecular complexes of 4-NH,-benzophenone with bismuth(II1) halides and with iodine IDA
VEZZCSI, ALINE FRANCAZANOLIand GIORGIO F’EYRONEL lstituto di Chimica Generale e Inorganica, University of Modena,
MARIA
41100 Modena, Italy (Receiued21 January 1978). Abstract-The following solid complexes of CNHr-benzophenone (L) with bismuth (III) chloride. bromide and iodide and with iodine were prepared: BiC13.L (yellow), BiCl,.ZL (red), 3BiBr,.ZL (orange), BiBrx.2L (red). 2BiIs.3L (red). 1.L (yellow). 1.2L (orange). 1.3L (red). The iodine complexes are obtained from ethanolic solutions of BiIJ and the ligand. by precipitation with water or ligroin, the iodide ion being oxydized to iodine by the oxygen dissolved in the solvents. From an oxygen free hgroin-ethanolic solution only 2 BiI,.3L is obtained. The i.r. spectra of the solids show that in the yellow or orange BiX3 complexes the NH, group is involved into the coordination while in the red BiXa complexes and in the orange and red iodine complexes the v(NH) bands of the ligand remain unaltered. The carbonylic oxygen is not involved in the coordination. In DCM solution the red BiX, complexes and all the iodine complexes show a C.T. band at 440420 nm, the energy of which gives a linear plot versus the electron affinity of the three halogens. The electronic spectra of the solids show a C.T. band in the region 470-500 nm.
INTRODUCTION
In previous works we have prepared and investigated in the solid state and in solution the molecular complexes of antimony(II1) and bismuth(II1) chloride and bromide with pyrene [l, 21, of antimony(I11) chloride and bromide with benzophe%one and 4-R-benzophenones (R =Cl. Br. NH21 [3] and ofbismuth(III)chloride and bromide with benzophenone and CR-benzophenones (R =Cl. Br. Me) [4]. Benzophenone gives solid complexes with the halides of several other elements [5-73. The complexes of CNH,-benzophenone with bismuth(II1) chloride, bromide and iodide and with iodine have now been prepared and investigated in the solid state and in solution for a comparison with the corresponding antimony(II1) halide complexes.
EXPERIMENTAL The ligand was purified by recrystallization from petroleum ether. The bismuth trihalides (Hopkins and Williams) were dried on P20,. All the solvents were dehydrated and kent on metallic sodium. Dichloromethane (DCM) for sp&trophotometric measurements (Merck) was dehydrated with &Cl2 and fractionally distilled collecting the fraction distillina at 40°C. All the manipulations were done and all the reag&ts and vessels were kept in a dry box on P20s. The complexes were prepared as follows: BiCI, . (4NH*-Ph&O): by adding the solid ligand to a saturated solution of Bit& in DCM a microcrystalline yellow product precipitates. BiClj. 2(4-NH,-Ph,CO): a DCM solution saturated with both the reagents becomes deep red giving. after some days, a very thick red mud which, by washing it several times with ligroin or petroleum ether. is transformed into a red powder. Some time well shaped red crystals grow on the wall of the vessel. 3BiBr,.2(4-NH,-Ph,CO): the orange microcrystalline product is obtained by adding petroleum ether to a DCM solution containing an excess of BiBr, with respect to the
&and or by diluting a DCM solution saturated with both tmr=%ents BiBr, .2(4-NHs-PhrCO): by adding petroleum ether to a concentrated DCM solution of the reagents, containing a large excess of the ligand, a red mud is formed which, by washing it several times with ligroin, is transformed into a red powder. 1. (4NH*-PhrCO): by adding an equimolecular quantity of the soiid ligand to a solution of BiI, in ethanol the colour of the solution becomes deep yellow, and by adding water under strong stirring the crystalline needle-like yellow product precipitates. 1.2(4-NH,-PhsCO): the orange microcrystalline product precipitates by adding water under stirring to an ethanolic solution of BiI, containing an excess of the ligand. 1. 3(4-NH*-PhrCO): by adding ligroin to an ethanolic solution saturated with BiI, and the ligand the crystalline deep red product precipitates. ZBiI, . 3(4-NH2-Ph*CO): by adding oxygen free ligroin to an oxygenfree ethanolic solution saturated with BiI, and the ligand a red oil is formed which crystallizes, by standing in the mother solution, into a red powder. Ah the compounds are stable in air and soluble in several organic solvents. From an ethanolic solution of iodine and an excess of CNH,-Ph,CO by adding water only the free ligand precip itates and by adding ligroin only a change of colour is obtained. From a DCM solution of iodine and an excess of +NH,-Ph&O by adding cyclohexane a yellow product precipitates which becomes red and contains a large excess of the free ligand. The compounds were analysed (Table 1) by combustion for C, H, N and by titrating the halide ions in aqueous acidic solution by the Vohlard method. The electronic spectra were recorded on the solutions with a Beckman DK 1A spectrophotometer and on the solids in Nujol mulls on quartz plates with a Shimadzu MPS-SOL spectrophotometer and the i.r. spectra on the solids in KBr disks (4000-250 cm- ‘) with a Perkin-Elmer 521 spectrophotometer (Table 2). RESULTS
AND DISCUSSION
Two types of solid complexes, yellow-orange and red, are formed by 4-NH,-Ph,CO with bismuth(II1) chlor-
106
IDA
MARIAVEZZOSI,ALINEFRANCAZANOLIand GIORGIOPEYRONEL Table 1. Analytical data. found % (calcd. %)
BiClJ.(4-NH*-Ph&O) BiCI,.2(4-NH2-Ph,CO) 3BiBr,.2(4-NHt-Ph2CO) BiBrs.2(4-NH*-Ph,CO) 2BiIJ.3(4-NH,-Ph,CO) I.(4-NH2-Ph&O) 1.2(4-NH,-Ph2CO) 1.3(4-NH,-Ph,CO)
Colour
C
H
N
X
yellow red orange red red yellow orange red
29.12(30.43) 42.87(43.95) 18.32(17.94) 36.48(37.00) 26.3q26.42) 50.02(48.26) 59.2q59.88) 65.07(65.18)
2.16(2.14) 3.00(3.09) 1.12(1.32) 2.68(2.60) 2.02(1.86) 4.28(3.39) 4.1E44.22) 4.7q4.60)
2.28(2.73) 3.77(3.94) 1.67(1.61) 3.43(3.32) 2.18(2.37) 4.83(4.32) 5.18(5.37) 5.53(5.85)
20.68(20.75) 15.06(14.98) 40.97(41.32) 28.2q28.42) 38.9q39.15) 23.43(24.38) 18.09(17.69)
Table 2. Infrared (cm-‘) and electronic (nm) CT. bands of the ligand and its complexes
4-NH*-Ph&O BiCII.(4-NHt-PhzCO) BiCla.2(4-NH,-Ph,CO) 3BiBr,.2(4-NH*-Ph,COj BiBr3.2(4-NH2-Ph&O) 2BiI,.3(4-NHI-Ph2CO) 1.(4-NH2-Ph,CO) 1.2(4-NH,-Ph,CO) 1.3(4-NHz-Ph,CO) I2 +4-NH*-Ph,CO in DCM
v(NH)
v(CO)
3423m 3343ms 3225m 3430wb 3355w,sh 3105m,sh 3045msb 3415dmb 3312ms 3190wm 3405wmb 3310m 3180~ 2905m 3415wmb 3320ms 3197mw 3450m 335Oms 3205m
1630~s 1640s 1620s 1610s 1618s 1615s
3400ms 3316s 3204ms 3402ms 3320s 3208ms .
1625~s 1624~s
C.T. band
440 430,392 434 422 423 423 420
ide and bromide as with antimony(II1) chloride and bromide [3]. Only the red 2BiIa * 3(4-NHz-Ph2CO) complex could be isolated from oxygen free ethanolligroin solutions. Three iodine complexes are formed from Bi13 and the ligand in oxygen-containing solutions.
of two different complexes in solution. The red complexes BiCIB *2(4-NH,-Ph&O), BiBr, . 2(4-NH2-Ph2CO) and 2BiIJ. 3(4-NHz-PhzCO) give only one rather strong band at 440,434 and 422 nm, respectively, which remains unaltered even with a large excess of ten times of the ligand. The three iodine complexes obtained from
The i.r. v(C0) frequency of the ligand remains almost unaltered in the complexes, its variations (Tom + 10 to -20 cm-‘) being attributable to weak intermolecular interactions; a metal-ligand bonding through the carbonylic oxygen may therefore be excluded. The v(NH) bands of all the “red” halide complexes (Table 2 and Fig. 1) are well shaped and almost identical to those of the ligand while they are very deformed for the “yellow” or “orange” complexes. This indicates, as for the antimony(II1) chloride and bromide complexes [S]. that in the “yellow-orange” form the NH,-group is N-bonded to the bismuth halide while it is not involved in the formation of the solid red complexes. In DCM solution (3.10-%) 4-NH2-Ph2C0 shows two sharp bands at 313 and 238 nm which remain unaltered in the complexes. The yellow complex BiCIS *+I-NH*-Ph,CO) does not show any distinct C.T. band in the visible region, while the orange complex 3BiBr3. 2(4-NH,-Ph,CO) gives two C.T. maxima at 430 and 392 nm (Fig. 2), attributable to the existence
Bi13 give in DCM solution the same spectrum (Fig. 2)
showing unaltered the two strong ligand bands at 313 and 238 nm and a new C.T. band at 423 nm. The same C.T. band at 420 nm is given by the DCM solution of iodine (4*10-(M) and 4-NH2-Ph$O (1.6. 10e3@. A plot of the hv values of the C.T. bands of the red BiCI,. BiBr, and Bi13 complexes versus the electronic affinity (Eu) [8] of the halogens gives a straight line in agreement with the assumption [9] that the wavelength at the maximum of the C.T. band for a series of complexes increases with the increase in the electron affinities of the acceptor. The iodine compounds obtained from Bi13 do not show any i.r. v(NH:) or v(OH+) bands indicating a protonation from HI molecules formed by hydtolysis of Bi13, their v(NH) bands being identical to those of the ligand, and their electronic spectra in DCM solution are identical to that of the DCM solution of Iz and CNH,-Ph,CO. As these complexes are formed only in oxygen containing solutions an oxidation of the
Molecular complexes of CNH&enzophenone
: c
b
1
:
I
I
VG I
I
107
(410-430 run) in which appears the visible band of the iodine complexes with donors at a nitrogen atom [ 111. This band is shifted to 435-470 nm and at 490-510 nm for donors at an oxygen atom and for aromatic or ethylene hydrocarbons, respectively [ll]. Structures like CsHSN+ . CH31- [9] and (PyI)+I- or Py’I; [lo] have been proposed. The C.T. band at 420-423 nm seems therefore to indicate a N+I- interaction for the iodine (4-NH2Ph,CO) complexes in DCM solution. An ionic form is also supported by the molar conductivity of 2(4-NH2Ph$O)I(h=61 in 1.33.10m3 M and 73 in CL~.~O-~M methanol solution) for which a constitution in solution like @-NH,-Ph,CO);Imay be proposed. As in the solid state these complexes show i.r. v(NH) bands almost identical in position and intensity to those of the l&and, independently from their orange or red colour, while a N+I- interaction should substantially alter these bands, it is likely that in the solid state another type of coordination occur, in which the n-electrons of the aromatic ring are involved.
1
3500
3000 cm-'
Fig. 1. Infrared v(NH) and VfCH) bands of: (a) CNHZbenzophenone (4-NH,-PhrCO); (b) BiBr, .2(4-NH*-Ph,CO), red;(c) 3Biljra . 2(4-NH2-R&O), orange; (d) BfCls .2@&NH,-Ph,CO), red; (e) BiCl, . (4-NHa-PhrCO), yellow.
EO
3.0-
Fig. 3. Plot of the electron affinity En (eV) of chlorine (3.61) bromine (3.36) and iodine (3.06) [E] versus the C.T. band energies hv (eV) of the red complexes: BiCl, .2(4-NH2Ph,CO) (2.817), BiBr, .2(4-NH,-PhaCO) (2.856); 2BiI,. 3(4-NH2-Ph,CO) (2.930). Also the “red” complexes I 360
1
I 400
I
I 440 "Ill
#
I
I
460
Fig. 2. Electronic spectra in dichloromethane solution of: (a) 3BiBr,. 2(4-NH,-Ph,CO), orange; (b) BiBr, 2(4-NH2Ph,CO), red; (c) I,(4. 10e4 M)+4-NH,-PhrCO (1.6. 10m3 M);(d) 1.3(4-NH,-Ph,CO), red. iodide ion of BiI, by the oxygen dissolved in the solution must occur. Iodine gives with pyridine in n-heptane solution a C.T. band at 422 nm [lo], and at about 410 nm with triethylamine in n-heptane [ 111, in the spectral region
of the ligand with BiC13,
BiBr, and Bi13 show unaltered the v(NH) bands of the ligand in the solid state (Fig. 1) and have electronic spectra in DCM solution very similar to those of the iodine complexes (Fig. 2). The electronic spectra of the solids recorded in Nujol mull on quartz plate show for the three red complexes BiCl,.2(4-NH,-Ph,CO), BiBr3.2(4-NH2Ph,CO) and 1’3(4-NH1-Ph,CO) a very large C.T. band, the maximum of which lies in the region 470-500 nm. This confirms that in the solid state the red complexes have a coordination different than in solution, the position of the C.T. band indicating that in the solid state the aromatic rings of the ligand may be involved into the coordination.
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[5] B. P. Susz and P. CHALANDON, He/o. Chim. Acta 41, 1332 (1958). [6] R. C. PALL and S. L. CHADHA.J. Inorg. Nucl. Chem. 30. 1679 (1968). [7] V. BALZANIand L. MAGGI,Ann. Chimica 53.166 (1963). [8] F. A. COTTONand G. WILKINSON.Advanced Inorganic REFERENCES Chemistry, Wiley-Interscience. New York (1972). [9] L. J. ANDREWS and R. M. KEEFERMolecular Complexes G. PEYRONEL, I. M. VEZZ~U and S. BUFFAGNI,Inorg. in Organic Chemistry. pp. 24 and 137, Holden-Day. Chim. Acta 4,605 (1970). San Francisco (1964). G. B~MBIERI,G. PEYRONEL and I. M. VEZZOSI,Inorg. [lo] C. REID and R. S. MULLIKEN,J. Am. Chem. Sot. 76, Chim. Acta 6, 349 (1972). 3869 (1954). I. M. VEZZOSI,G. PEYRONEL and A. F. ZANOLI,Spectro[ 1l] R. S. MULLIKENand W. B. PERSON.Molecular Comchim. Acta 32A, 679 (1976). plexes. A Lecture and Reprint Volume, pp. 157-158. I. M. VEZZOSI. A. F. ZANOLI and G. PEYRONEL, John Wiley, New York (1969). Spectrochim. Acta 34A, 651 (1978).
Acknowledgements-This work was supported by a financial aid from the Consiglio Nationale delle Richerche (CNR) of Italy.
[l] [2] [3] [4]