- Email: [email protected]
Vibrational spectra of some adducts of tin tetraiodide
Notes
1209
3O
28
'"< 2e S $
2,* I
12
I
14
1(5
I
18
LogloA Fig. 4. The iso-kinetic relationship for the reaction trans- [Co(en)2CI=]~++H=O [Co(en)~CIH~O]z++CI- in various aqueous solvents as follows: (1) 60% methanol, (2) 60% dioxan, (3) 40% dioxan, (4) 39% methanol, (5) 60% acetone, (6) 54% ethanol, (7) 36% ethanol, (8) 40% acetone, (9) 18% ethanol, (10) 20% dioxan, (11) 20% methanol, (12) 20% acetone, (13) water.
Acknowledgement-The author thanks the donors of the Petroleum Research Fund administered by the American Chemical Society for support.
Chemistry Department University of the West Indies Mona, Kingston 7 Jamaica
G. C. LALOR
J. inorg, nucl. Chem., 1969, Vol. 3 I, pp. 1209 to 1212.
Pergamon Press.
Printed in Great Britain
V i b r a t i o n a l spectra of s o m e a d d u c t s o f t i n t e t r a i o d i d e (Received 9 May 1968) THe uSE of vibrational spectroscopy to assign the stereochemistry of 6-coordinate complexes has been well documented [ 1]. The examination of metal iodide adducts, however, has not been complete because of the lack of instruments capable of detecting metal-iodine vibrations. We report here the
I. I. R. Beattie, T. Giison, M. Webster and G. P. McQuillan, J. chem. Soc. 238 (1964); and references therein.
1210
Notes
cq
t~
O~
J
u e,
t~
u
t~
Z t 'q
Z
t'q
'~
..O O3
Notes
1211
far i.r, and Raman spectra of adducts of tin tetraiodide using an intefferometric instrument (far i.r.) and laser excitation (Raman). The adducts of tin tetraiodide with pyridine, trimethylamine, triphenylphosphine oxide, l : 1 0 phenathroline, 2,2'-bipyridyl and tetramethylethylenediamine (TMEN) were prepared. All were found to have bands (i.r. and Raman) due to Sn--I stretching modes at frequencies below v3 for Snl4 (216 cm -1) (Table 1). For these L2SnL adducts (L = ligand) we can expect cis or trans stereochemistry for the adducts with monodentate ligands but cis stereochemistry for the adducts with bidentate ligands. The most complex spectra were obtained from the adducts with pyridine, triphenylphosphine oxide, 2,2'-bipyridyl and 1 : 10-phenanthroline where three or four bands in the region 130-200 cm -1 due to Str--1 stretching modes were observed. If a cis configuration is expected then we can predict from symmetry considerations, four coincident i.r. and Raman active fundamentals due to Srr--I stretching modes, whereas a centrosymmetric trans adduct has only one i.r. active mode. In general Raman spectra* for the above four adducts showed some coincidences with i.r. abst~rption bands. We are unable to find a suitable solvent for these adducts in order to examine solution spectra. Our results cannot therefore provide conclusive evidence for cis stereochemistry in the above cases since splitting of the eu mode of a trans adduct due to solid state effects could lead to similar multiplicity of Str--I modes. The spectra of the T M E N adduct and the trimeth•lamine adduct are simpler than the previous examples, with no apparent Raman-i.r. coincidences. This may be due to trans stereochemistry for the trimethylamine adduct and for the T M E N adduct the possibility of a trans bridging structure cannot be excluded. Some far i.r. absorbtion bands of the triphenylphosphine oxide adduct [2] and the bipyridyl adduct [3] have been assigned to metal-donor atom stretching modes on the basis that these new bands are not perturbations of ligand or acceptor modes. It has been shown that mixing of donor and acceptor modes can occur to a considerable extent with trimethylamine as a ligand and may occur in other similar systems[4]. We do not propose to specifically assign particular bands in the region approximately 200-450 cm -1 as being due primarily to metal-donor atom modes. It is interesting to note that the M~issbauer spectra (usSn resonance) of the pyridine and bipyridyl adducts gave only single resonances with no quadrupole splitting. Quadrupole splittings have been observed in 6-coordinate organo-tin adducts but not in the bipyridyl adducts with tin tetrachloride and bromide [5]. We report our observed isomer shifts for these two adducts and for tin tetraiodide, in Table 2.
Table 2. M6ssbauer spectra* of tin compounds Compound
Snl4 SnI4.2 (pyridine) SnI4.(2,2'-bipyridyl)
Isomer shift (mm/sec) 1,50 1.00 1.00
1.45 1.05 1.05
*The spectra were obtained at liquid nitrogen temperature and all shifts are relative to stannic oxide.
* Raman spectra were only obtained using the instrument at high sensitivity where high background noise was encountered, consequently only the strongest bands could be detected.
2. 3. 4. 5.
J. P. Clark, V. M. Langford and C. J. Wilkins, J. chem. Soc. A 792 (1967). M. F. Farona and J. G. Grasselli, Inorg. C h e m . 6, 1675 0967). I. R. Beattie and F. W. Parrett, J. chem. Soc. A 1784 (1966). M. A. Mullins and C. Curran, Inorg. C h e m . 6, 2017 (1967).
1212
Notes
EXPERIMENTAL The trimethylamine adduct was prepared by the method of Fowles [6]. Other adducts were prepared by adding the ligand in dry toluene to tin tetralodide in dry toluene. Analyses are given in Table 3. Infrared spectra were determined using Nujol mulls of the solids with the R.I.I.C. FS-720 intefferometer. Raman spectra were determined on solid adducts using the Cary 81 with H e - N e laser excitation. Table 3. Analytical results Compound
SnI4.TEMEN SnI4.2NMe3 SnI4.bipy Sni4.2 pyridine Snl4.1,10 phen SnI4.2Ph3PO
Found I (%) 66.8 69.7 63-0 63.5 50.9 42.5
Calcd. I (%)
66.4 69.4 63-0 63-6 51.3 42.6
67.9 68.4 62-9 64.3 51.5 42.8
Acknowledgements-We thank the S.R.C. for a grant to purchase the FS-720, Professor I. R. Beattie for use of the Cary 8 l, and Mr. J. M. Brown of Albright and Wilson Mfg. Ltd., for the determinations of M6ssbauer spectra. K. G. H U G G I N S F. W. PARRETI" H. A. P A T E L
Department of Chemistry University of Surrey London, S.W.11 6. G . W . A . Fowles and R. A. Hoodless,J. chem. Soc. 33 (1963).
J. inorg,nucI.Chem.,1969,Vol.31,pp. 1212to1213. PergamonPress. Printedin Great Britain
Addendum to paper entitled "The theory of regular solutions applied to the viscosity of dilute solutions of chromium(llI) acetylacetonate in organic solvents" (Received5 June 1968) In deriving a value of the coefficient So in the empirical equation 7/~,. = 1 +SoX2+S~X2 ~ from the theoretical relationship
~ L = ( VI°/V,)e{ (-8~X2(VI + I/2) + 2X~P'~8~)/ART} which appears as Equation (l 1) in the above paper[l], we introduced the approximation VtqVs -:- 1 for very dilute solutions. This led to Equation (I 5), viz. So = ( - 6 ~ ( V 1 ° + I~2) + 21?26182)/ART. 1. H. M. N. H. Irving and J. S. Smith, J. inorg, nucl. Chem. 30, 1873 (1968).
1209
3O
28
'"< 2e S $
2,* I
12
I
14
1(5
I
18
LogloA Fig. 4. The iso-kinetic relationship for the reaction trans- [Co(en)2CI=]~++H=O [Co(en)~CIH~O]z++CI- in various aqueous solvents as follows: (1) 60% methanol, (2) 60% dioxan, (3) 40% dioxan, (4) 39% methanol, (5) 60% acetone, (6) 54% ethanol, (7) 36% ethanol, (8) 40% acetone, (9) 18% ethanol, (10) 20% dioxan, (11) 20% methanol, (12) 20% acetone, (13) water.
Acknowledgement-The author thanks the donors of the Petroleum Research Fund administered by the American Chemical Society for support.
Chemistry Department University of the West Indies Mona, Kingston 7 Jamaica
G. C. LALOR
J. inorg, nucl. Chem., 1969, Vol. 3 I, pp. 1209 to 1212.
Pergamon Press.
Printed in Great Britain
V i b r a t i o n a l spectra of s o m e a d d u c t s o f t i n t e t r a i o d i d e (Received 9 May 1968) THe uSE of vibrational spectroscopy to assign the stereochemistry of 6-coordinate complexes has been well documented [ 1]. The examination of metal iodide adducts, however, has not been complete because of the lack of instruments capable of detecting metal-iodine vibrations. We report here the
I. I. R. Beattie, T. Giison, M. Webster and G. P. McQuillan, J. chem. Soc. 238 (1964); and references therein.
1210
Notes
cq
t~
O~
J
u e,
t~
u
t~
Z t 'q
Z
t'q
'~
..O O3
Notes
1211
far i.r, and Raman spectra of adducts of tin tetraiodide using an intefferometric instrument (far i.r.) and laser excitation (Raman). The adducts of tin tetraiodide with pyridine, trimethylamine, triphenylphosphine oxide, l : 1 0 phenathroline, 2,2'-bipyridyl and tetramethylethylenediamine (TMEN) were prepared. All were found to have bands (i.r. and Raman) due to Sn--I stretching modes at frequencies below v3 for Snl4 (216 cm -1) (Table 1). For these L2SnL adducts (L = ligand) we can expect cis or trans stereochemistry for the adducts with monodentate ligands but cis stereochemistry for the adducts with bidentate ligands. The most complex spectra were obtained from the adducts with pyridine, triphenylphosphine oxide, 2,2'-bipyridyl and 1 : 10-phenanthroline where three or four bands in the region 130-200 cm -1 due to Str--1 stretching modes were observed. If a cis configuration is expected then we can predict from symmetry considerations, four coincident i.r. and Raman active fundamentals due to Srr--I stretching modes, whereas a centrosymmetric trans adduct has only one i.r. active mode. In general Raman spectra* for the above four adducts showed some coincidences with i.r. abst~rption bands. We are unable to find a suitable solvent for these adducts in order to examine solution spectra. Our results cannot therefore provide conclusive evidence for cis stereochemistry in the above cases since splitting of the eu mode of a trans adduct due to solid state effects could lead to similar multiplicity of Str--I modes. The spectra of the T M E N adduct and the trimeth•lamine adduct are simpler than the previous examples, with no apparent Raman-i.r. coincidences. This may be due to trans stereochemistry for the trimethylamine adduct and for the T M E N adduct the possibility of a trans bridging structure cannot be excluded. Some far i.r. absorbtion bands of the triphenylphosphine oxide adduct [2] and the bipyridyl adduct [3] have been assigned to metal-donor atom stretching modes on the basis that these new bands are not perturbations of ligand or acceptor modes. It has been shown that mixing of donor and acceptor modes can occur to a considerable extent with trimethylamine as a ligand and may occur in other similar systems[4]. We do not propose to specifically assign particular bands in the region approximately 200-450 cm -1 as being due primarily to metal-donor atom modes. It is interesting to note that the M~issbauer spectra (usSn resonance) of the pyridine and bipyridyl adducts gave only single resonances with no quadrupole splitting. Quadrupole splittings have been observed in 6-coordinate organo-tin adducts but not in the bipyridyl adducts with tin tetrachloride and bromide [5]. We report our observed isomer shifts for these two adducts and for tin tetraiodide, in Table 2.
Table 2. M6ssbauer spectra* of tin compounds Compound
Snl4 SnI4.2 (pyridine) SnI4.(2,2'-bipyridyl)
Isomer shift (mm/sec) 1,50 1.00 1.00
1.45 1.05 1.05
*The spectra were obtained at liquid nitrogen temperature and all shifts are relative to stannic oxide.
* Raman spectra were only obtained using the instrument at high sensitivity where high background noise was encountered, consequently only the strongest bands could be detected.
2. 3. 4. 5.
J. P. Clark, V. M. Langford and C. J. Wilkins, J. chem. Soc. A 792 (1967). M. F. Farona and J. G. Grasselli, Inorg. C h e m . 6, 1675 0967). I. R. Beattie and F. W. Parrett, J. chem. Soc. A 1784 (1966). M. A. Mullins and C. Curran, Inorg. C h e m . 6, 2017 (1967).
1212
Notes
EXPERIMENTAL The trimethylamine adduct was prepared by the method of Fowles [6]. Other adducts were prepared by adding the ligand in dry toluene to tin tetralodide in dry toluene. Analyses are given in Table 3. Infrared spectra were determined using Nujol mulls of the solids with the R.I.I.C. FS-720 intefferometer. Raman spectra were determined on solid adducts using the Cary 81 with H e - N e laser excitation. Table 3. Analytical results Compound
SnI4.TEMEN SnI4.2NMe3 SnI4.bipy Sni4.2 pyridine Snl4.1,10 phen SnI4.2Ph3PO
Found I (%) 66.8 69.7 63-0 63.5 50.9 42.5
Calcd. I (%)
66.4 69.4 63-0 63-6 51.3 42.6
67.9 68.4 62-9 64.3 51.5 42.8
Acknowledgements-We thank the S.R.C. for a grant to purchase the FS-720, Professor I. R. Beattie for use of the Cary 8 l, and Mr. J. M. Brown of Albright and Wilson Mfg. Ltd., for the determinations of M6ssbauer spectra. K. G. H U G G I N S F. W. PARRETI" H. A. P A T E L
Department of Chemistry University of Surrey London, S.W.11 6. G . W . A . Fowles and R. A. Hoodless,J. chem. Soc. 33 (1963).
J. inorg,nucI.Chem.,1969,Vol.31,pp. 1212to1213. PergamonPress. Printedin Great Britain
Addendum to paper entitled "The theory of regular solutions applied to the viscosity of dilute solutions of chromium(llI) acetylacetonate in organic solvents" (Received5 June 1968) In deriving a value of the coefficient So in the empirical equation 7/~,. = 1 +SoX2+S~X2 ~ from the theoretical relationship
~ L = ( VI°/V,)e{ (-8~X2(VI + I/2) + 2X~P'~8~)/ART} which appears as Equation (l 1) in the above paper[l], we introduced the approximation VtqVs -:- 1 for very dilute solutions. This led to Equation (I 5), viz. So = ( - 6 ~ ( V 1 ° + I~2) + 21?26182)/ART. 1. H. M. N. H. Irving and J. S. Smith, J. inorg, nucl. Chem. 30, 1873 (1968).