Reactions of tetra-µ-carboxylato-diruthenium(II,II) compounds. X-Ray crystal structures of Ru2(µ-O2CCF3)4(thf)2, Ru2(µ-O2CR)4(NO)2(R = Et or CF3), and {Na3[Ru2(µ-O2CO)4]·6H2O}n

Improved procedures for the synthesis of the diruthenium(II) carboxylates, Ru2(µ-O2CR)4L2, and substitutions of either the bridged carboxylate or axial ligands (L) are described. Among new bridged compounds are the trifluoroacetate, Ru2(µ-O2CCF3)4, the carbonate, {Na3[Ru2(µ-O2CO)4]·6H2O}n, and the triazenide, Ru2(µ-N3Ph2)4; adducts of the triazenide include the nitrosyl, Ru2(µ-N3Ph2)4(NO)2, the isocyanide, Ru2(µ-N3Ph2)4(ButNC), and the carbonyl Ru2(µ-N3Ph2)4(CO)2. Reactions of the carboxylates with donors such as isocyanides, pyridine (py), phosphines, or CO leads in some cases to bridge cleavage and products such as trans-Ru(O2CR)2(py)4 or Ru(O2CR)2(PPh3)2(R = Me or CF3), while the reactions with NO yield the diamagnetic adducts Ru2(µ-O2CR)4(NO)2. Infrared, n.m.r., e.s.r., and electronic spectra are recorded together with cyclic voltammetric studies. The X-ray crystal structures of the dimers Ru2(µ-O2CCF3)4(thf)2(thf = tetrahydrofuran) and Ru2(µ-O2CR)4(NO)2(R = Et or CF3), and the polymer {Na3[Ru2(µ-O2CO)4]·6H2O}n are reported.