Subvalent Group 4B metal alkyls and amides. Part II. The chemistry and properties of bis[bis(trimethylsilyl)methyl]tin(II) and its lead analogue

Abstract

Bis[bis(trimethylsiiyl)methyl]tin, SnR2, has an extensive chemistry, behaving as (i) a Lewis base, (ii) a Lewis acid, or (iii) undergoing oxidative addition (insertion reactions). The following complexes have been isolated, many as well characterised crystals. For class (i), these include (M = Cr or Mo)[M(CO)5(SnR2)], trans-[M(CO)4-(SnR2)2], [Fe2(η-C5H5)2(CO)3(SnR2)], [RhCl(PPh3)2(SnR2)], and [PtCl(PEt3)(SnR2)(SnR2Cl)]: for class (ii), the readily thermally-dissociable 1 : 1 adducts with pyridine, 4-methylpyridine, or piperidine, and for class (iii), SnR2(A)B (AB = HCl,HF, MeI, RCl, Cl2, Br, O2, CH2:CMeCMe:CH2, [Mo(η-C5H5)(CO)3X](X = H or Me), [Fe(η-C5H5)(CO)2X](X = Cl or Me), [{Fe(CO)4}2]. and [PtCl2(PEt3)(SnR2)]). An interesting feature is the appearance in the 1H n.m.r. spectra of doublets characteristic of diastereotopicallv distinct SiMe3 groups in compounds of the form SnR2(A)B (A ≠ B). The complex [Mo(CO)5(PbR2)] has also been obtained.