The Crystal and Molecular Structure of an Isomer of Bis-(1,2-diethoxycarbonyl-ethyl)tin Dibromide

Abstract

Low mp isomer of bis-(1,2-diethoxycarbonyl-ethyl)tin dibromide (mp 114–115°C) crystallizes in a monoclinic form: a=11.85, b=20.24, c=9.79 Å, β=101.3°; space group, P2₁/a; and four molecules are contained in a unit cell. Crystal structure was established by the heavy atom method. The coordination about the tin atom is nearly octahedral. Two bromine atoms attached to the tin atom are in cis-positions. Two ligands, 1,2-diethoxycarbonyl-ethyl groups, are both bound to the tin atom by carbon and oxygen, forming five-membered rings. These rings are rather puckered, and one is in d-form and another in l-form.