catena-(μ3-Bromo)di(μ2-bromo)bromo(18-crown-6)dilead(II): Synthesis and crystal structure

A new polymeric complex, catena-(μ3-bromo)di(μ2-bromo)bromo(18-crown-6)dilead(II), [Pb2Br(μ2-Br)2(μ3-Br)(18-crown-6)] n (I), is synthesized, and its crystal structure is studied using X-ray diffraction analysis (space group P $$ \bar 1 $$ , a = 7.970, b = 16.048, c = 19.153 Å, α = 72.75°, β = 88.57°, γ = 87.92°, Z = 4, direct method, full-matrix least-squares method in the anisotropic approximation, R = 0.076 for 6093 independent reflections, CAD4 automated diffractometer, λMoKα radiation). The crystal structure of complex I contains infinite chains of the PbBr6 octahedra along the x axis with the bridging Br− anions as common edges. The [PbBr(18-crown-6)]+ host-guest complex fragments are attached through weak Pb-Br bonds to these chains on the side. In two independent terminal fragments, the coordination polyhedra of the Pb2+ cations are distorted hexagonal bipyramids with bases of six O atoms of the crown ligand and two Br− anions in the axial vertices. Two Pb2+ cations from the [PbBr3] − infinite polymer chain have a distorted octahedral coordination.