Cobalt Salen Complexes for Catalytic Hydrogen Production

Several cobalt salen complexes were synthesized. Early solubility issues were solved by adding cyclohexyl and phenyl substituents to the diamine backbone of the ligand. Crystals were obtained for complexes 18, 20, and 21. These complexes represent a series of compounds differing only in number of electron withdrawing substituents. Cyclic voltammetry was performed on 18, 20, and 21 to probe the catalytic activity of each compound. Initial CVs were taken in acetonitrile solutions. Subsequent CVs were taken with additions of TFA to prove the catalytic activity of each complex. It was found that 21, containing the most electron withdrawing substituents, was the most active and had the most positive redox couple followed by 20. 18 exhibited a very negative redox couple at -1.37 V and showed no catalytic activity

Equation of motion approach to the Hubbard model in infinite dimensions

We consider the Hubbard model on the infinite-dimensional Bethe lattice and construct a systematic series of self-consistent approximations to the one-particle Green's function, $G^{(n)}(\omega),\ n=2,3,\dots\$ . The first $n-1$ equations of motion are exactly fullfilled by $G^{(n)}(\omega)$ and the $n$'th equation of motion is decoupled following a simple set of decoupling rules. $G^{(2)}(\omega)$ corresponds to the Hubbard-III approximation. We present analytic and numerical results for the Mott-Hubbard transition at half filling for $n=2,3,4$.Comment: 10pager, REVTEX, 8-figures not available in postscript, manuscript may be understood without figure