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Triorganotin Fluoride Structures: A Ligand Close‐Packing Model with Predominantly Ionic Sn−F Bonds
Author(s) -
Beckmann Jens,
Horn Dagmar,
Jurkschat Klaus,
Rosche Fred,
Schürmann Markus,
Zachwieja Uwe,
Dakternieks Dainis,
Duthie Andrew,
Lim Allan E. K.
Publication year - 2003
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200390022
Subject(s) - chemistry , crystallography , ionic bonding , pyridine , ab initio , intermolecular force , crystal structure , ab initio quantum chemistry methods , infrared spectroscopy , ligand (biochemistry) , ion , molecule , organic chemistry , biochemistry , receptor
The synthesis and complete characterization by multinuclear NMR, infrared, and Mössbauer spectroscopy, by single crystal X‐ray analysis, as well as by electrospray mass spectrometry of the new soluble triorganotin fluoride Me 2 PhSnF ( 1 ) is reported. The crystal structure of 1 reveals a rod ‐ like polymeric structure in the solid state. Solutions of 1 in apolar solvents, such as toluene, contain mixtures of interconvertible oligomers. Ab initio MO calculations on model compounds H 3 SnF, [H 3 SnFSnH 3 ] + , and [FH 3 SnFSnH 3 F] − indicate that the Sn−F bonds are substantially ionic in character, and suggest open‐chain species, rather than cyclic species. In donor solvents, such as pyridine, 1 forms complexes with the solvent, such as Me 2 PhSnF·pyridine. The solid‐state structure of (Me 3 SiCH 2 ) 3 SnF ( 2 ) is reformulated as monomeric with a weak intermolecular Sn ··· F interaction that gives rise to a [4+1] coordination. The relative short Sn−Sn separation enables the fluorine atoms to oscillate (flip‐flop) between two neighboring (Me 3 SiCH 2 ) 3 Sn− groups, which is expressed in the X‐ray experiment by a dynamic disorder. Ab initio MO calculations on a model compound, [H 3 SnFSnH 3 ] + , suggest only a small energy barrier for the flip‐flop motion. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2003)