Synthesis and Crystal Structure of the Alkylbismuth Diiodides: A Family of Extended One-Dimensional Organometallic Compounds

Abstract

Crystals of the organometallic compounds CnH2n+1+BiI2 (n = 2,4) have been grown under solvothermal conditions, using a reaction between R3Bi (R = C2H5, C4H9) and BiI3, in a diethyl ether solution. Both compounds crystallize in the orthorhombic space group Pbam with the unit cell parameters a = 15.228(1) Å, b = 10.964(1) Å, b = 4.3505(2) Å, and Z = 4, for C2H5BiI2, and a = 25.515(2) Å, b = 8.4192(6) Å, c = 4.3467(2) Å, and Z = 4, for C4H9BiI2. The solid state structures of these two compounds, when compared with the recently reported CH3-BiI2 (n = 1) structure, demonstrate that the alkylbismuth diiodides form a family of extended one-dimensional organic-inorganic materials. The framework of the RBiI2 (R = alkyl) chains in each compound is virtually identical, with each bismuth having a square pyramidal coordination of four iodines in the basal plane and a covalently bonded terminal carbon from an alkyl group in the apical site. Each basal square shares trans edges with two nearest neighbors to form a one-dimensional BiI2 chain, with the alkyl groups aligned on one side of the BiI2 basal plane. The Bi(III) lone pair is stereochemically active and extends into the space trans to each alkyl group. The principle difference between the members of this family derives from the stacking of the RBiI2 chains in the overall structure. This study demonstrates the flexibility to accommodate a range of different length organic constituents within a basic extended one-dimensional organometallic framework.