Synthesis and crystal structures of iodoplumbate chains, ribbons and rods with new structural types

Abstract

One-dimensional infinite iodoplumbates with new structural types have been prepared by crystallization from solutions containing PbI₂ and NaI with large counter ions. Whereas [(PhCH₂)₄P]₂[Pb₃I₈] 1 contains Pb^II with octahedral and square pyramidal coordination, in [Me₃N(CH₂)₆NMe₃][PbI₃]₂2, [Na(dmf)₃]₄[Pb₆I₁₆] 3, [Na₄(dmf)₁₄][PbI₃]₄4, [PrN(C₂H₄)₃NPr][Pb₂I₆] 5 and [Bu₃N(CH₂)₂NBu₃]₂[Pb₁₀I₂₄] 6 all Pb atoms are six-coordinated. The great structural variety of these compounds is achieved by condensation of PbI₆ octahedra in several different ways. Face-sharing octahedra are observed in 2 and 4, edge-sharing octahedra characterize the anionic substructure of 6. In the iodoplumbates 3 and 5 PbI₆ octahedra share common faces, edges and vertices at the same time. The Pb–I distances ranging from 293.5 to 364.5 pm can be explained on the basis of different degrees of bridging of the iodo ligands and the trans influence of ligands in trans position. The composition and structure of the iodoplumbate anions are mainly determined by the size, shape and charge of the counter ions used for crystallization.