PREPARATION AND STRUCTURAL CHARACTERIZATION OF 3 TETRAKIS(TRIAZENO)DIRUTHENIUM COMPOUNDS

Three closely related diruthenium triazeno complexes, Ru2[(p-tolyl)NNN(p-tolyl)]4(CH3CN) (1), Ru2(PhNNNPh)4 (2) and Ru2[(p-tolyl)NNN(p-tolyl)]4(CH3CN).BF4 (3), have been synthesized and structurally characterized. Direct cocrystallization of Ru2[(p-tolyl)NNN(p-tolyl)]4 with CH3CN affords the dark red 1 in space group P4/n with a = 14.851(3), c = 11.942(7) angstrom, V = 2634(2) angstrom 3 and Z = 2. The purple 2 was crystallized in space group P1BAR with a = 13.720(5), b = 15.901(4), c = 10.388(4) angstrom, alpha = 103.92(3), beta = 94.56(3), gamma = 99.11(3)-degrees, V = 2155(1) angstrom 3 and Z = 2. The dark green 3 was obtained by oxidizing Ru2[(p-tolyl)NNN(p-tolyl)]4 with Ag(CH3CN)4BF4, and crystallized in space group P2/n with a = 13.280(2), b = 16.816(5), c = 13.095(4) angstrom, beta = 90.16(2)-degrees, V = 2924(2) angstrom 3 and Z = 2. The Ru-Ru bond lengths determined through diffraction studies are 2.407(1), 2.3994(6) and 2.373(1) angstrom for 1, 2 and 3, respectively. The results of both magnetic susceptibility and EPR measurements on 3 consistently confirm a pi(*)3 ground state configuration as previously predicted.