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Preparation and i.r. spectra of some diaryltindicupferrates
1546
Notes
J, inorg, nucL Chem., 1975, Vo[, 37, pp. 1546-1547. Pergamon Press. Printed in Great Britain
Preparation and i.r. spectra of some diaryltindicupferrates (Received 1 August 1974)
THE AMMONIUMsalt of N-nitrose-N-phenyl hydroxylamine cupferron) is a well known analytical reagent for the quantitative determination of Cu(II), Fe(II) and many other ions[l]. The interaction of the reagent with R2SnCI2 (R = phenyl, o-, m- or p-tolyl) was studied with a view to examining its suitability for the quantitative precipitation of the bipositive organotin moiety, but inspire of several attempts under varying conditions, complete precipitation of the group was not found possible. Four new diaryltindicupferrates of the formula R2Sn(C6HTN30~h were however isolated in the solid state. Their characterization and i.r. spectral data are reported in this communication. The complexes were obtained by mixing acetonic solution of diaryltindichloride with a solution of cupferron in the same solvent. The mixture was stirred for a couple of hours and the precipitated product was filtered, washed with acetone and recrystallized from benzene. The analytical data and the molecular weight of the complexes in freezing benzene are given in Table 1. Diaryltin dicupferrates are brown solids, unaffected by atmospheric oxygen and moisture. They melt sharply in the range 110-150°C and are soluble in common organic solvents. Their i.r. spectra using a P.E. 521 grating spectrophotometer were recorded in the range 4000-300 cm-' and possible assignments to fundamental modes of vibration are summarized in Table 2. The data indicate that the absorptions associated with the aromatic ring of the Lewis base such as C-H, C=C stretchings, ring vibrations and C-H in-plane and out-of-plane deformations appear at their usual positions in the spectra of the complexes and are not significantly affected in coordination. Two very intense absorptions due to the N=O stretching mode appearing at 1282 and 1237 in the spectrum of the free ligand are greatly shifted towards lower frequency side and occur at 1220 _ 5 and 1170 respectively in the spectra of the complexes indicating coordination from the oxygen atom of the N=O group and consequent weakening of the band due to electron drainage. It is rather surprising that Bottei and Schenggenburger[2] identified
this mode of vibration in the spectra of some divalent-metal chelates of cupferron and dicupferron at a higher frequency than in the free ligand. However, Thakur et a/.[3] in a later communication observed a distinct negative shift of this absorption in the spectra of certain rare-earth cupferrates. In the region 1300-1400 of the spectra, besides a strong ring vibration at 1300, two vibrational modes associated with C-N and N-N stretchings are expected to occur. Thakur et a/.[3] have assigned an absorption around 1370 to the former and the one at 1328 to the latter mode of vibration. In the present investigation it has not been possible to identify the C-N stretching mode with certainty. Yoshimura et al.[4] have also failed to locate this absorption in the i.r. spectra of cupferron and neocupferron. The N-N stretching mode, however, appears as a strong band at 1340 with a shoulder at 1334 in the spectrum of cupferron. The position of this absorption in the complexes is slightly shifted towards the higher frequency side and is in agreement with the observations of Thakur et al. [3]. Two strong absorptions appearing at 910 and 570 have been assigned to ONNO skeletal bending and NNO deformation modes Table
1.
R Phenyl
Experimental data for diaryltindicupferrates R2Sn(C6HsN2Ozh
m.p. 110-11
o-tolyl* 120-21 m-tolyl* 135-36 p-tolyl* 149-50
rnol. wt. Sn 561 20.0 (501) (20.4) 582 19.0 520 19.3 569 19.4 (609) (19.5)
Analysis % C 48.7 (49.4) 54.7 54.6 54.6 (53.5)
C-H stretching C=C ring stretching
H-N Stretching ring vibration NC Stretching C-H in plane deformation ring vibration Skeletal bending ONNO C-H out-of-plane deformation C=C ring out of plane deformation N-N-O bending Sn-O-Stretching (tentative)
Cupferron (NH, salt)
3.9 (4.5) 4.6 4.7 4.8 (5.1)
14.7 (14.4) 13.5 13.0 13.9 (13.7)
*Calculated values for o-, m- and p-tolyl compounds are the same.
Table 2. I,R. absorption frequencies (cm -~) for R2Sn (cupferrateh
Assignment
Found/(Calc.) H N
R Phenyl
o-tolyl
m-tolyl
p-tolyl
3060 w 1600 w 1498 m 1470 s 1450 m 1340 vs 1334 sh 1300 vs 1282 vs 1237 vs 1078 m 1062 m 1025 m 910 vs
3060w 1580m 1495 s 1475 s 1448 s 1352 vs
3050w 1580m 1495 s 1475 s 1448 s 1352 vs
3050w 1580m 1492 s 1475 s 1448m 1350 s
3050w 1580rn 1495 s 1475 s
1310 vs 1215 s 1172 vs 1078 sh 1070 s 1026 s 920 vs
1300 s 1225 s 1170m 1074 sh 1062 s 1025 m 918 vs
1300 s 1220 s 1170 m 1070 sh 1060 s 1022 m 918 vs
1305 s 1215 m 1170 vs
860 m 752 s 685 vs
860 sh 752 vs 682 s
862 w 753 s 680 s
752 s 678 s
862 w 755 s 680 s
570 s
595 s 560 mbr
585 s 565 br
580 ssh 565 sh
600 m 565 br
s--strong; m--medium; w = weak; v = very; sh = shoulder; br = broad.
1350 s
1065 s 1020 m 922 vs
Notes respectively. Both of these absorption sundergo small positive shift on complexation indicating the chelated structure of the complexes resulting from bonding through both the oxygen atoms of the base to the tin atom. An absorption around 565 slightly broad in shape identified in the spectra of all the complexes but absent in the spectrum of cupferron is assigned to the Sn-O stretching mode which agrees well with the reported value for the absorption around 570[5, 6]. The analytical results showing 1 : 2 stoichiometry and the spectral data indicating chelate formation, therefore, suggest a hexacoordihated tin atom in diaryltindicupferrates.
Acknowledgements--Thanks are due to the Chairman, Chemistry Department, McGill University, Montreal for affording laboratory facilities to record the i.r. spectra and to the National Research Council of Canada for the award of research associateship.
1547
Chemistry Department Lucknow University Lucknow India
T. N. SRIVASTAVA
REFERENCES 1. F. J. Welcher, Organic Analytical Reagents, Vol. III, p. 355. Van Nostrand, New York (1947). 2. R. S. Bottie and R. G. Schneggenburger. J. inorg, nucl. Chem. 32, 1525 (1970). 3. N. V. Thakur, V. B. Kartha, C. R. Kanekar and V. R. Marathe, J. inorg, nucl. Chem. 34, 2831 (1972). 4. T. Yoshimura, C. Miyake and S. Imote, Bull. Chem, Soc. Japan 45, 1424 (1972). 5. R. C. Poller, J. inorg, nucl. Chem. 24, 935 (t962). 6. R. S. Tobias and C. E. Freidline, lnorg. Chem. 4, 215 (1%5).
J inore,nucl Chem..1975.Vol.37. pp. 1547-1548. PergamonPress Printedin GreatBritain
Cu(II), Ni(II) and Co(II) complexes of N-phenyl-benzothiazolyl thiocarbamide (Received 23 March 1974) SEVERAL complexes of the thiocarbamides[l-4] have been prepared. Nothing has appeared about the metal complexes of Nphenyl-N'-benzothiazolyl thiocarbamide. We have synthesised the Cu(II), Ni(II) and Co(II) complexes of N-phenyl-N'benzothiazolyl thiocarbamide. The composition and the structure of the complexes have been explored by spectrophotometric and conductometric studies using an extraction technique. It establishes the ratio 1 : 2 (M: L) for the complexes.
Nature of the complexes in solution The extraction technique was applied with Job's method of continuous varation [7] as modified by Vosburg and Cooper [8] as well as the mole ratio method [9]. In this technique, the volume of chloroform and aqueous layers were kept constant. After thorough shaking, the chloroform and aqueous layers were used for spectrophotometric and conductometric studies respectively. Each method gave the metal and ligand ratio as 1:2.
EXPERIMENTAL
DISCUSSION The i.r. spectrum of L shows a number of strong, sharp and broad bands in the region 3000-3166 cm -1 and 1572 cm -j which are assigned to NH stretching and bending vibrations respectively. It also shows a sharp absorption at 1645 and 726 cm-' indicating the presence of ~,C-~-~N(cyclic) and ~,C=S respectively. RaG and Venkatraghavan[10] pointed out that where nitrogen atoms are attached to the thiocarbonyl group, there seems to be three regions in which a C=S vibration, coupled with other vibrations, may be observed. Recently the contribution of the C=S stretching vibration [ l 1, 12] has been reported. The i.r. spectrum of L shows three bands at 1510, 1182, 945 cm -~. These bands show an appreciable shift to higher frequencies which indicate an M-S linkage in the complexes. The vicinity of the vC~--~-Sbands also confirm the M-S linkage. The lowering in ~,C=N (cyclic) frequencies in the complexes show a coordinate link from the nitrogen atom to the metal. The ~,M-N vibrations in the Cu(II), Ni(II) and Co(It) complexes usually appear in the region 400-600 cm -~ [13-15]. The appearance of vM-N and ~M-S vibrations in the Cu(II), Ni(II) and Co(II) complexes which are absent in the ligand can be seen from Table 1. The magnetic moment of the Cu(II) complex ( / ~ = 2.34 B.M.) corresponds to spin only and indicates a square planar structure. Magnetic moments[16] ranging from 3'5 to 4.2 B.M. and 4.1 to 4.7 B.M. are associated with tetrahedral Ni(II) and Co(II) complexes respectively. The observed magnetic moments of our Ni(II) and Co(II) complexes,/xo~ = 3 B.M. and/zo, = 4.6 B.M. respectively confirm the tetrahedral configuration.
The standard solutions of cupric, nickel and cobalt chlorides were prepared in distilled water. The standard solution of the ligand was prepared in chloroform. The absorbance was measured with a Bausch-Lomb Spectronic 20 spectrophotometer. Conductance measurements were made on a Beckman Conductivity Bridge. A Coleman-Analyser was used for the estimation of carbon, hydrogen and nitrogen. Infrared spectra in KBr matrices were recorded on a Perkin-Elmer (Model-621) and are listed in Table l. The magnetic susceptibility was determined by a Cahn Electrobalance (Model-7550) using mercuric tetrathiocyanato cobaltate(II) as the standard and using the gram susceptibility value[5]. Diamagnetic correction was applied by the use of Pascal's constants. The absorbance at 420 nm and above were chosen because the metals and ligand have no absorption in these regions while complexes absorb strongly.
N-Phenyl-N'-Benzothiazolyl Thiocarbamide (L): was prepared by the method of Bhargava et al. [6] Preparation of Cu(II), Ni(II) and Co(III) complexes The Cu(II) complex was obtained by boiling cupric chloride and ligand (1:2) in ethanol. Ethanolic solutions of nickel and cobalt(II) chlorides were mixed with the ligand (1:2), pH was adjusted to 10 and the mixtures then boiled for 30 rain. After cooling, and dilution with water, the complexes were filtered and dried. The products were extracted into chloroform, chloroform distilled off and dried over anhydrous CaCIa. Analytical data and colour are recorded below:
%M Complex C28HaoNrS4Cu CasHaoNrS,Ni CasHaoNrS,Co
Colour Dirty green Yellowish green Redish brown
%C
%H
Found
Calc.
Found
Calc.
10.51 9.72 --
10.07 9.36 --
53,31 53.20 . . . 53.91 53.59
%N
Found
Calc.
Found
Calc.
3.16
3.17
3.33
3.19
-13.33 13.71
-13-41 13.40
.
Notes
J, inorg, nucL Chem., 1975, Vo[, 37, pp. 1546-1547. Pergamon Press. Printed in Great Britain
Preparation and i.r. spectra of some diaryltindicupferrates (Received 1 August 1974)
THE AMMONIUMsalt of N-nitrose-N-phenyl hydroxylamine cupferron) is a well known analytical reagent for the quantitative determination of Cu(II), Fe(II) and many other ions[l]. The interaction of the reagent with R2SnCI2 (R = phenyl, o-, m- or p-tolyl) was studied with a view to examining its suitability for the quantitative precipitation of the bipositive organotin moiety, but inspire of several attempts under varying conditions, complete precipitation of the group was not found possible. Four new diaryltindicupferrates of the formula R2Sn(C6HTN30~h were however isolated in the solid state. Their characterization and i.r. spectral data are reported in this communication. The complexes were obtained by mixing acetonic solution of diaryltindichloride with a solution of cupferron in the same solvent. The mixture was stirred for a couple of hours and the precipitated product was filtered, washed with acetone and recrystallized from benzene. The analytical data and the molecular weight of the complexes in freezing benzene are given in Table 1. Diaryltin dicupferrates are brown solids, unaffected by atmospheric oxygen and moisture. They melt sharply in the range 110-150°C and are soluble in common organic solvents. Their i.r. spectra using a P.E. 521 grating spectrophotometer were recorded in the range 4000-300 cm-' and possible assignments to fundamental modes of vibration are summarized in Table 2. The data indicate that the absorptions associated with the aromatic ring of the Lewis base such as C-H, C=C stretchings, ring vibrations and C-H in-plane and out-of-plane deformations appear at their usual positions in the spectra of the complexes and are not significantly affected in coordination. Two very intense absorptions due to the N=O stretching mode appearing at 1282 and 1237 in the spectrum of the free ligand are greatly shifted towards lower frequency side and occur at 1220 _ 5 and 1170 respectively in the spectra of the complexes indicating coordination from the oxygen atom of the N=O group and consequent weakening of the band due to electron drainage. It is rather surprising that Bottei and Schenggenburger[2] identified
this mode of vibration in the spectra of some divalent-metal chelates of cupferron and dicupferron at a higher frequency than in the free ligand. However, Thakur et a/.[3] in a later communication observed a distinct negative shift of this absorption in the spectra of certain rare-earth cupferrates. In the region 1300-1400 of the spectra, besides a strong ring vibration at 1300, two vibrational modes associated with C-N and N-N stretchings are expected to occur. Thakur et a/.[3] have assigned an absorption around 1370 to the former and the one at 1328 to the latter mode of vibration. In the present investigation it has not been possible to identify the C-N stretching mode with certainty. Yoshimura et al.[4] have also failed to locate this absorption in the i.r. spectra of cupferron and neocupferron. The N-N stretching mode, however, appears as a strong band at 1340 with a shoulder at 1334 in the spectrum of cupferron. The position of this absorption in the complexes is slightly shifted towards the higher frequency side and is in agreement with the observations of Thakur et al. [3]. Two strong absorptions appearing at 910 and 570 have been assigned to ONNO skeletal bending and NNO deformation modes Table
1.
R Phenyl
Experimental data for diaryltindicupferrates R2Sn(C6HsN2Ozh
m.p. 110-11
o-tolyl* 120-21 m-tolyl* 135-36 p-tolyl* 149-50
rnol. wt. Sn 561 20.0 (501) (20.4) 582 19.0 520 19.3 569 19.4 (609) (19.5)
Analysis % C 48.7 (49.4) 54.7 54.6 54.6 (53.5)
C-H stretching C=C ring stretching
H-N Stretching ring vibration NC Stretching C-H in plane deformation ring vibration Skeletal bending ONNO C-H out-of-plane deformation C=C ring out of plane deformation N-N-O bending Sn-O-Stretching (tentative)
Cupferron (NH, salt)
3.9 (4.5) 4.6 4.7 4.8 (5.1)
14.7 (14.4) 13.5 13.0 13.9 (13.7)
*Calculated values for o-, m- and p-tolyl compounds are the same.
Table 2. I,R. absorption frequencies (cm -~) for R2Sn (cupferrateh
Assignment
Found/(Calc.) H N
R Phenyl
o-tolyl
m-tolyl
p-tolyl
3060 w 1600 w 1498 m 1470 s 1450 m 1340 vs 1334 sh 1300 vs 1282 vs 1237 vs 1078 m 1062 m 1025 m 910 vs
3060w 1580m 1495 s 1475 s 1448 s 1352 vs
3050w 1580m 1495 s 1475 s 1448 s 1352 vs
3050w 1580m 1492 s 1475 s 1448m 1350 s
3050w 1580rn 1495 s 1475 s
1310 vs 1215 s 1172 vs 1078 sh 1070 s 1026 s 920 vs
1300 s 1225 s 1170m 1074 sh 1062 s 1025 m 918 vs
1300 s 1220 s 1170 m 1070 sh 1060 s 1022 m 918 vs
1305 s 1215 m 1170 vs
860 m 752 s 685 vs
860 sh 752 vs 682 s
862 w 753 s 680 s
752 s 678 s
862 w 755 s 680 s
570 s
595 s 560 mbr
585 s 565 br
580 ssh 565 sh
600 m 565 br
s--strong; m--medium; w = weak; v = very; sh = shoulder; br = broad.
1350 s
1065 s 1020 m 922 vs
Notes respectively. Both of these absorption sundergo small positive shift on complexation indicating the chelated structure of the complexes resulting from bonding through both the oxygen atoms of the base to the tin atom. An absorption around 565 slightly broad in shape identified in the spectra of all the complexes but absent in the spectrum of cupferron is assigned to the Sn-O stretching mode which agrees well with the reported value for the absorption around 570[5, 6]. The analytical results showing 1 : 2 stoichiometry and the spectral data indicating chelate formation, therefore, suggest a hexacoordihated tin atom in diaryltindicupferrates.
Acknowledgements--Thanks are due to the Chairman, Chemistry Department, McGill University, Montreal for affording laboratory facilities to record the i.r. spectra and to the National Research Council of Canada for the award of research associateship.
1547
Chemistry Department Lucknow University Lucknow India
T. N. SRIVASTAVA
REFERENCES 1. F. J. Welcher, Organic Analytical Reagents, Vol. III, p. 355. Van Nostrand, New York (1947). 2. R. S. Bottie and R. G. Schneggenburger. J. inorg, nucl. Chem. 32, 1525 (1970). 3. N. V. Thakur, V. B. Kartha, C. R. Kanekar and V. R. Marathe, J. inorg, nucl. Chem. 34, 2831 (1972). 4. T. Yoshimura, C. Miyake and S. Imote, Bull. Chem, Soc. Japan 45, 1424 (1972). 5. R. C. Poller, J. inorg, nucl. Chem. 24, 935 (t962). 6. R. S. Tobias and C. E. Freidline, lnorg. Chem. 4, 215 (1%5).
J inore,nucl Chem..1975.Vol.37. pp. 1547-1548. PergamonPress Printedin GreatBritain
Cu(II), Ni(II) and Co(II) complexes of N-phenyl-benzothiazolyl thiocarbamide (Received 23 March 1974) SEVERAL complexes of the thiocarbamides[l-4] have been prepared. Nothing has appeared about the metal complexes of Nphenyl-N'-benzothiazolyl thiocarbamide. We have synthesised the Cu(II), Ni(II) and Co(II) complexes of N-phenyl-N'benzothiazolyl thiocarbamide. The composition and the structure of the complexes have been explored by spectrophotometric and conductometric studies using an extraction technique. It establishes the ratio 1 : 2 (M: L) for the complexes.
Nature of the complexes in solution The extraction technique was applied with Job's method of continuous varation [7] as modified by Vosburg and Cooper [8] as well as the mole ratio method [9]. In this technique, the volume of chloroform and aqueous layers were kept constant. After thorough shaking, the chloroform and aqueous layers were used for spectrophotometric and conductometric studies respectively. Each method gave the metal and ligand ratio as 1:2.
EXPERIMENTAL
DISCUSSION The i.r. spectrum of L shows a number of strong, sharp and broad bands in the region 3000-3166 cm -1 and 1572 cm -j which are assigned to NH stretching and bending vibrations respectively. It also shows a sharp absorption at 1645 and 726 cm-' indicating the presence of ~,C-~-~N(cyclic) and ~,C=S respectively. RaG and Venkatraghavan[10] pointed out that where nitrogen atoms are attached to the thiocarbonyl group, there seems to be three regions in which a C=S vibration, coupled with other vibrations, may be observed. Recently the contribution of the C=S stretching vibration [ l 1, 12] has been reported. The i.r. spectrum of L shows three bands at 1510, 1182, 945 cm -~. These bands show an appreciable shift to higher frequencies which indicate an M-S linkage in the complexes. The vicinity of the vC~--~-Sbands also confirm the M-S linkage. The lowering in ~,C=N (cyclic) frequencies in the complexes show a coordinate link from the nitrogen atom to the metal. The ~,M-N vibrations in the Cu(II), Ni(II) and Co(It) complexes usually appear in the region 400-600 cm -~ [13-15]. The appearance of vM-N and ~M-S vibrations in the Cu(II), Ni(II) and Co(II) complexes which are absent in the ligand can be seen from Table 1. The magnetic moment of the Cu(II) complex ( / ~ = 2.34 B.M.) corresponds to spin only and indicates a square planar structure. Magnetic moments[16] ranging from 3'5 to 4.2 B.M. and 4.1 to 4.7 B.M. are associated with tetrahedral Ni(II) and Co(II) complexes respectively. The observed magnetic moments of our Ni(II) and Co(II) complexes,/xo~ = 3 B.M. and/zo, = 4.6 B.M. respectively confirm the tetrahedral configuration.
The standard solutions of cupric, nickel and cobalt chlorides were prepared in distilled water. The standard solution of the ligand was prepared in chloroform. The absorbance was measured with a Bausch-Lomb Spectronic 20 spectrophotometer. Conductance measurements were made on a Beckman Conductivity Bridge. A Coleman-Analyser was used for the estimation of carbon, hydrogen and nitrogen. Infrared spectra in KBr matrices were recorded on a Perkin-Elmer (Model-621) and are listed in Table l. The magnetic susceptibility was determined by a Cahn Electrobalance (Model-7550) using mercuric tetrathiocyanato cobaltate(II) as the standard and using the gram susceptibility value[5]. Diamagnetic correction was applied by the use of Pascal's constants. The absorbance at 420 nm and above were chosen because the metals and ligand have no absorption in these regions while complexes absorb strongly.
N-Phenyl-N'-Benzothiazolyl Thiocarbamide (L): was prepared by the method of Bhargava et al. [6] Preparation of Cu(II), Ni(II) and Co(III) complexes The Cu(II) complex was obtained by boiling cupric chloride and ligand (1:2) in ethanol. Ethanolic solutions of nickel and cobalt(II) chlorides were mixed with the ligand (1:2), pH was adjusted to 10 and the mixtures then boiled for 30 rain. After cooling, and dilution with water, the complexes were filtered and dried. The products were extracted into chloroform, chloroform distilled off and dried over anhydrous CaCIa. Analytical data and colour are recorded below:
%M Complex C28HaoNrS4Cu CasHaoNrS,Ni CasHaoNrS,Co
Colour Dirty green Yellowish green Redish brown
%C
%H
Found
Calc.
Found
Calc.
10.51 9.72 --
10.07 9.36 --
53,31 53.20 . . . 53.91 53.59
%N
Found
Calc.
Found
Calc.
3.16
3.17
3.33
3.19
-13.33 13.71
-13-41 13.40
.