Application of a stereochemical model to the mononuclear complexes of tin

T. K. SHAM, J. S. TSE, V. WELLINGTON, and G. M. BANCROFT. Can. J. Chem. 55,3487 (1977). The synthesis and Mossbauer spectra of 16 organotin compounds of the type MePhSnX, (X = F, Cl), [Et4N]MePhSnC1,, MePhSnClzLz (L = oxygen and nitrogen neutral donor ligands), and MePhSnLzf (L' = acetylacetonates and 8-hydroxyquinolate) are reported. The Mossbauer quadrupole splittings (qs) are used to assign the structures of the complexes. The MePhSnX, (X = F, C1) compounds have similar structures to their Me2Sn analogues, while the six-coordinate complexes show a greater structural similarity to their Ph2Sn analogues. Thus MePhSnF, is a highly associated structure like Me2SnF2 with a six-coordinate Sn atom; while the MePhSnL,' complexes have the cis structure like their PhzSn analogues. The structures of the six-coordinate organotin complexes are rationalized using steric calculations and the known bonding properties of the ligands. The quadrupole splittings and centre shifts (cs) are also used to suggest variations in ligand bonding properties, and to discuss variations in C-Sn-C angles from the MePhSn complexes to their PhzSn analogues. . Les dedoublements quadrupolaires (dq) tires des spectres Mossbauer sont utilisCs pour determiner la structure des complexes. Les composCs MePhSnX, (X = F, C1) ont une structure similaire a leurs analogues Me,Sn alors que les complexes hexacoordonnes montrent une plus grande similarite structurale B leurs analogues Ph,Sn. Le compose MePhSnF, a une structure trts associke comme Me2SnF2 et possede un atome Sn hexacoordonne; tandis que les complexes MePhSnL,' possedent une structure cis comme leurs analogues Ph,Sn. Les structures des complexes organostanniques hexacoordonnes sont rationalisees en faisant appel a des calculations steriques et des propriites liantes deja connues pour ces ligands. Les dCdoublements quadrupolaires ainsi que le centre des deplacements (cd) sont aussi utilises pour expliquer les variations des propriCt6s liantes du ligand et de discuter les variations des angles C-Sn-C lorsqu'on passe des complexes MePhSn a leurs analogues PhzSn.[Traduit par le journal] Introductioll The stereochemistry of diorganotin compounds has been a subject of recent interest (1-3). The variable C-Sn-C angle in Me2Sn compounds has been rationalized using ligandligand repulsion calculatioils (2), and the Mossbauer quadrupole splittings (qs) are useful for estimating this angle (1, 3). However, the stereochemical preference of trans and cis configurations in six-coordinate dimethyl and diphenyl compounds is not clearly understood. Accun~ulated X-ray structures (1, 3, 4) of dimethyl tin compounds indicate that with the exception of Me,Sn(oxin), (5) [oxin = anion of 8-hydroxyquinoline] and Me,Sn(ONHCOMe,) (6), all the six-coordinate dimethyl tin compounds have the trans or distorted trans configurations.

Section: Results and Discussion ( I ) Chemistrymentioning

confidence: 96%

Preparation and Mössbauer spectra of organotin(IV) compounds containing the CH₃(C₆H₅)Sn(IV) moiety

Sham¹,

Tse²,

Wellington³

et al. 1977

“…The problem of assessing the relative stabilities of InX,L, species has been discussed in detail elsewhere (13) on the basis of the model of ligand steric angles developed by Zahrobslcy (14). The general conclusion is that the cis isomer will be the more stable of the two, since the total repulsive nonbonded contacts are minimized in this form.…”

Section: Indium-chlorinementioning

confidence: 99%

The Crystal and Molecular Structure of Dichloro(acetylacetonato)-2,2′-bipyridylindium(III)

Contreras¹,

Einstein²,

Tuck³

1974

The molecular structure of dicholoro(acetylacetonato)-2,2′-bipyridylindium(III) has been determined from three dimensional X-ray data collected by counter methods. The structure has been refined by least-squares techniques to a conventional R factor of 4.3% for the 3524 observed reflections. Crystals of Cl2In(acac)(bipy) are monoclinic, a = 11.340(3), b = 12.198(3), c = 14.330(3) Å, β = 120.25(2)°, z = 4, space group P21/c. The chloride ligands are cis, with In—Cl at distances of 2.443(1) and 2.394(1) Å; the In—O bond lengths are 2.124(3) and 2.164(3) Å, and the In—N bond distances are 2.276(4) and 2.299(4) Å.

“…are seldom equal. In order to apply K e~e r t ' s model mode1s based on ligand-ligand to obtain bond angles, the concept of steric angle (5) have been proposed to account semiquan-is incorporated into Kepert's model. Thus, in the t i t a t i v e l~ for the in the C-Sn-C present model, we suggest that the repulsion between angles and the cis-trans preference in some organotin two dollor atoms i j is inversely proportional to c O n l~O u n d s (5)(6)(7).…”

Section: Introductionmentioning

confidence: 99%

Stereochemistry of six coordinate organotin(IV) compounds with bidentate ligands

Tse¹,

Sham²,

Bancroft³

1979

Extended ligand–ligand repulsion calculations have been applied to a number of six coordinate organotin complexes of the type RR′Sn(bidentate)2 (R, R′ = Me, Ph, Cl). Qualitatively, the calculations readily predict the decrease in the R—Sn—R′ angle with decrease in bite size of the bidentate ligand. The steric calculations are generally successful in predicting both the cis–trans preference of the R groups and the bond angles about the Sn atom. For the Me2Sn complexes, electronic effects (as expressed by Bent's rule) sometimes have to be used in conjunction with the steric calculations to rationalize the observed stereochemistry.