om0508536_si_005.cif (70.53 kB)

[(tBu2PCH2SiMe2)2N]RuMe2:  Synthesis and Reactivity of an Unsaturated Ruthenium Dialkyl Radical Species

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posted on 27.02.2006, 00:00 by Michael J. Ingleson, Maren Pink, John C. Huffman, Hongjun Fan, Kenneth G. Caulton
The reaction of PNPRuCl (PNP = (tBu2PCH2SiMe2)2N-) with excess MeLi at −78 °C, followed by addition of a one-electron oxidant, leads to the thermally stable (at 25 °C), low-spin, five-coordinate trivalent ruthenium complex PNPRuMe2, 1. For comparison PNPRuI2, 2, was also synthesized and shown equally to be a low-spin d5 complex. Compound 1 reacts with NO to produce the diamagnetic ruthenium(II) complex PNPRuMe2(NO), 3, with H2 to give PNPRu(H)3, 5, and with excess CO to produce PNPRu(COMe)CO, 6. The unusual stability of 1 is suggested to arise from the steric encapsulation of the radical center provided by the extremely bulky pincer ligand, the low coordination number (5), and a non-redox-innocent amide functionality.