Spin alignment in organic high-spin molecules as studied by ESR and the generalized Hubbard Hamiltonian approach

Abstract

In order to examine the role of topological symmetry in spin alignment of organic high-spin molecules, a novel hydrocarbon, 3,4′-diphenylmethylenebis(phenylmethylene) (3,4′-DPBPM), has beeen synthesized and characterized by single-crystal ESR. This molecule has a triplet ground state with a closely located quintet excited state in contrast to its topological isomer, 3,3′-DPBPM, with a non-degenerate septet ground state. UHF SCF calculation of the generalized Hubbard Hamiltonian satisfactorily predicts these results.