Synthesis, Molecular Structure and Reactions of Stable Square-Planar 16-Electron Ruthenium(0) Complexes: trans-[RuCl(NO)(PR3)2]

The reduction of [RuCl3(NO)(PPh3)2] (1) with Zn/Cu generates [RuCl(NO)(PPh3)2] that by ligand exchange with PR3 (R3  iPr3, iPr2Ph) affords the stable 16‐electron ruthenium (0) complexes trans‐[RuCl(NO)(PR3)2] (2, 3). The X‐ray structural analysis of 2 confirmed the square‐planar geometry around the metal center. HCl oxidatively adds to 2 and 3 to give the octahedral ruthenium(II) compounds [RuHCl2(NO)(PR3)2] (4, 5). On treatment of 2 and 3 with CO, TCNE, CH2 (generated from CH2N2) and O2, five‐coordinate 1:1 adducts [RuCl(NO)(L)(PR3)2] (6–12) are formed. The dioxygen complexes 11 and 12 react with SO2 to afford the sulfatoruthenium(II) derivatives [RuCl(NO){η2(O,O)‐O2SO2}(PR3)2] (13, 14). Compound 13 (R3  PiPr3) has been characterized by X‐ray structural analysis.