Between MOFs and molecules: organolead(IV) compounds with chain structures

Organolead compounds are of interest mainly as catalysts and organolead halides have proved to be very efficient materials for solar cells. Two organolead(IV) dimethylarsinates, namely catena-poly[[triphenyllead(IV)]-μ-chlorido-[triphenyllead(IV)]-μ-dimethylarsinato-κ²O:O'], [Pb₂(C₆H₅)₆(C₂H₆AsO₂)Cl]_n or [(Ph₃Pb)₂Cl(O₂AsMe₂)], (1), and poly[chlorido(μ₃-dimethylarsinato-κ³O:O,O':O')diphenyllead(IV)], [Pb(C₆H₅)₂(C₂H₆AsO₂)Cl]_n or [(Ph₂ClPb)(O₂AsMe₂)], (2), together with the triphenyllead(IV) diphenylphosphinate catena-poly[[triphenyllead(IV)]-μ-diphenylphosphinato-κ²O:O'], [Pb(C₆H₅)₃(C₁₂H₁₀O₂P)]_n or [(Ph₃Pb)(O₂PPh₂)], (3), have been synthesized and characterized by single-crystal X-ray diffraction, IR spectroscopy and mass spectrometry. In (1), a chain structure was found with alternating chloride and Pb-O-As-O-Pb arsinate bridges between five-coordinate Pb^IV atoms. In (2), bidentate and chelate-like bonded dimethylarsinate ligands form double chains with heptacoordinated Pb^IV atoms. In (3), a pentacoordinated Pb^IV atom is connected by Pb-O-P-O-Pb phosphinate bridges to form a linear chain. Obviously, the steric demand of the phenyl ligands at Pb^IV reduces the possibility of interconnections via polydentate ligands to one dimension only. Thus, no metal-organic frameworks (MOF) are formed but instead various chain structures are observed.