Syntheses and Reactions with Lewis Bases of Ru4(CO)8(.mu.3-O2C6H2R2)2 (R = H, t-Bu) Complexes Containing 1,2-Semiquinone Ligands Which Bridge through Oxygen and .eta.6-C6 Rings. Crystal Structures of Ru4(CO)8(O2C6H4)2.cntdot.CH2Cl2, Ru4(CO)8(O2C6H2(t-Bu)2)2.cntdot.2CH2Cl2, Ru4(CO)8(O2C6H2(t-Bu)2)2(py)2, and Ru4(CO)7(O2C6H2(t-Bu)2)2(PhC.tplbond.CCO2Et)