Crystalline binuclear cis- and trans-chlorotin(II) amides [Sn(µ-Cl)(NR2)]2, the cis-1a ⇌trans-1b isomerisation for [NR2= NCMe2(CH2)3CMe2], and the X-ray structures of 1a and of trans-[Sn(µ-Cl){N(SiMe3)2}]2

Abstract

Crystalline binuclear chlorotin(II) amides [Sn(µ-Cl)(NR₂)]₂ have been X-ray characterised as cis-[NR₂= [graphic omitted]Me₂, 1a] and trans-(R = SiMe₃, 2b) conformers [Cl–Sn–Cl′= 78.53(4)1a or 81.33(4)°2b, Sn–Cl–Sn′ 100.91(4)1a or 98.67(4)°2b, <Sn–Cl> 2.74 1a or 2.67 Å2b]; a solution of 1 in toluene undergoes rapid cis⇌trans exchange at ambient temperature, but distinct cis-1a and trans-1b forms coexist below 192 K (¹¹⁹Sn NMR spectroscopy and line-shape analysis) and evidence is presented for an intramolecular mechanism for this exchange.