Reprinted with permission from the Journal of the American Chemical Society. Copyright 2008 American Chemical Society.
Abstract: Density functional theory (DFT) has been used to assess the π-acidity and π-basicity of metal-organic trimetallic macromolecular complexes of the type [M(µ-L)]3, where M = Cu, Ag, or Au and L = carbeniate, imidazolate, pyridiniate, pyrazolate, or triazolate. The organic compounds benzene, triazole, imidazole, pyrazole, and pyridine were also modeled, and their substituent effects were compared to those of the coinage metal trimers. Our results, based on molecular electrostatic potential surfaces and positive charge attraction energy curves, indicate that the metal-organic macromolecules show superior π-acidity and -basicity compared to their organic counterparts. Moreover, the metal-organic cyclic trimers are found to exhibit π-acidity and -basicity that can be systematically tuned both coarsely and finely by judicious variation of the bridging ligand (relative π-basicity imidazolate > pyridiniate > carbeniate > pyrazolate > triazolate), metal (relative π-basicity Au > Cu > Ag), and ligand substituents. These computational findings are thus guiding experimental efforts to rationally design novel [M(µ-L)]3 materials for applications in molecular electronic devices that include metal-organic field-effect transistors and light-emitting diodes.
