Influence of Metal Fragment Mobility and Solution Dynamics on Cationic Rearrangements in Multimetallic Alkoxide Frameworks

摘要

abstract_textpMultimetallic alkoxides show manifold dynamics in solution comprising ligand switching among different sites (terminal, doubly or triply bridging), coordination lability of alkoxometallate units ({M(OR)(x)(-)}) and rearrangement of metal centers. Solution behavior and structural investigations of heterobimetallic iodide isopropoxides IM{Ce-2(OPri)(9)}(2) (M=Cd (1), Ba (2)) and corresponding potassium alkoxometallates of Sr and Al revealed equilibrium of several interconverting species that rearrange to form stable monomeric or dimeric trimetallic frameworks. Quantitative formation of dimeric heterotrimetallic alkoxides {Cd(OPri)(3)}Sr{Ce-2(OPri)(9)}(2) (3), {Cd(OPri)(3)}Ba{Ce-2(OPri)(9)}(2) (4) and monomeric {Al(OPri)(4)}(HOPri)Ba{Ce-2(OPri)(9)} (5) confirmed the tendency of metallo-fragments to rearrange themselves for achieving the maximum possible coordination number for constituent metals. Multinuclear NMR spectroscopy, elemental analysis, mass spectrometry and X-ray diffraction analyses verified the potential of electronically and sterically unsaturated alkoxometallate units in initiating the redistribution of metal centers./p/abstract_text