DIBENZO[B,I]-1,4,8,11-TETRAAZACYCLOTETRADECINE COMPLEXES .3. PREPARATION AND MOLECULAR-STRUCTURE OF AN UNPRECEDENTED DIRUTHENIUM(II) COMPOUND, RU2(HTMTAA)(O2CCH3)3(PHCCPH)

The unprecedented title compound, Ru2(C22H23N4)(O2CCH3)3(PhCCPh), where C22H23N4 = Htmtaa, has been prepared and studied by X-ray crystallography, cyclic voltammetry, and several forms of spectroscopy. The compound is diamagnetic as determined by NMR. The structure of the molecule has two notable features: The two ruthenium atoms, 2.633 (1) angstrom from each other, are of unequal coordination number and only one tmtaa ligand is bonded to the ''Ru2'' frame. The latter feature is of special interest since it presents the first example of a transition metal-tmtaa dimer in which the title ligand uses one of its four nitrogen atoms to bridge the metal centers. The title compound crystallizes as Ru2(C24H23N4)(O2CCH3)3(C6H5CCC6H5).C22H24N4.C7H8 in space group P1BAR with a = 15.526 (5) angstrom, b = 16.869 (6) angstrom, c = 13.170 (5) angstrom, alpha = 103.76 (3) degrees, beta = 108.98 (3) degrees, gamma = 94.48 (3) degrees, V = 3122 (2) angstrom3, and Z = 2.