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Polynuclear Transition Metal Complexes (polynuclear + transition_metal_complex)
Selected AbstractsBinuclear and Polynuclear Transition Metal Complexes with Macrocyclic Ligands.CHEMINFORM, Issue 40 2002Part 2. No abstract is available for this article. [source] Spin states in polynuclear clusters: The [Fe2O2] core of the methane monooxygenase active siteJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 12 2006Carmen Herrmann Abstract The ability to provide a correct description of different spin states of mono- and polynuclear transition metal complexes is essential for a detailed investigation of reactions that are catalyzed by such complexes. We study the energetics of different total and local spin states of a dinuclear oxygen-bridged iron(IV) model for the intermediate Q of the hydroxylase component of methane monooxygenase by means of spin-unrestricted Kohn,Sham density functional theory. Because it is known that the spin state total energies depend systematically on the density functional, and that this dependence is intimately connected to the exact exchange admixture of present-day hybdrid functionals, we compare total energies, local and total spin values, and Heisenberg coupling constants calculated with the established functionals BP86 and B3LYP as well as with a modified B3LYP version with an exact exchange admixture ranging from 0 to 24%. It is found that exact exchange enhances local spin polarization. As the exact exchange admixture increases, the high-spin state is energetically favored, although the Broken-Symmetry state always is the ground state. Instead of the strict linear variation of the energy splittings observed for mononuclear complexes, a slightly nonlinear dependence is found. The Heisenberg coupling constants JFe1Fe2,evaluated according to three different proposals from the literature,are found to vary from ,129 to ,494cm,1 accordingly. The experimental finding that intermediate Q has an antiferromagnetic ground state is thus confirmed. © 2006 Wiley Periodicals, Inc. J Comput Chem 27: 1223,1239, 2006 [source] About the calculation of exchange coupling constants in polynuclear transition metal complexesJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 8 2003Eliseo Ruiz Abstract The application of theoretical methods based on the density functional theory with hybrid functionals provides good estimates of the exchange coupling constants for polynuclear transition metal complexes. The accuracy is similar to that previously obtained for dinuclear compounds. We present test calculations on simple model systems based on H · · · He and CH2 · · · He units to compare with Hartree,Fock and multiconfigurational results. Calculations for complete, nonmodeled polynuclear transition metal complexes yield coupling constants in very good agreement with available experimental data. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 982,989, 2003 [source] | ||||||||||