Synthesis and small molecule reactivity of trans-dihydride isomers of Ru(NHC)2(PPh3)2H2 (NHC = N-Heterocyclic Carbene)

Caroline J. E. Davies, John P. Lowe, Mary F. Mahon, Rebecca C. Poulten, Michael K. Whittlesey

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)


Addition of IMe4 (1,3,4,5-tetramethylimidazol-2-ylidene) to Ru(PPh3)3HCl (in the presence of H2) or Ru(PPh3)4H2 gave the all-trans isomer of Ru(IMe4)2(PPh3)2H2 (1a), whereas 1,3-diethyl-4,5-dimethylimidazol-2-ylidene (IEt2Me 2) reacted with Ru(PPh3)4H2 to form cis,cis,trans-Ru(IEt2Me2)2(PPh 3)2H2 (2b). H/D exchange of 1a with C 6D6 (elevated temperature) or D2 (room temperature) gave Ru(IMe4)2(PPh3)2HD (1a-HD) and Ru(IMe4)2(PPh3)2D 2 (1a-D2). CO reacted with 1a to give a mixture of Ru(IMe4)2(PPh3)(CO)H2 (3) and Ru(IMe4)2(CO)3 (4); 2b reacted in a similar manner, although more slowly, allowing isolation of the monocarbonyl species Ru(IEt2Me2)2(PPh3)(CO)H2 (5). Insertion of CO2 into one of the Ru-H bonds of 1a and 2b generated mixtures of major and minor isomers of the κ2-formate complexes Ru(IMe4)2(PPh3)(OCHO)H (7/8) and Ru(IEt2Me2)2(PPh3)(OCHO)H (9/10). The hydridic nature of 1a and 2b was apparent by their reactivity toward MeI, which gave [Ru(IMe4)2(PPh3)2H]I (11), Ru(IEt2Me2)2(PPh3)HI (12), [Ru(IEt2Me2)2(PPh3)2H]I (13), and Ru(IEt2Me2)(PPh3)2HI (14). Complexes 1a, 2b, 5, 9, 11, 13, and 14 were structurally characterized.
Original languageEnglish
Pages (from-to)4927-4937
Number of pages11
Issue number17
Early online date23 Aug 2013
Publication statusPublished - 9 Sep 2013

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