Synthesis of new mer,trans-rhodium(III) hydrido-bis(acetylide) complexes: Structure of mer,trans-[(PMe3)3Rh(Ctriple bond; length of mdashC–C6H4-4-NMe2)2H]

Terminal alkynes (R–Ctriple bond; length of mdashC–H, R = 1-naphthyl, 9-anthryl, 4-Me2N–C6H4–, or the longer analogue, 4-(4-Me2N–C6H4–Ctriple bond; length of mdashC–)–C6H4–) react with [Rh(PMe3)4Me] at ambient temperature, with loss of methane and one PMe3 ligand, to form the corresponding mer,trans-[(PMe3)3Rh(Ctriple bond; length of mdashCR)2H] compounds in excellent yield. In this preliminary study, the synthesis and spectroscopic characterization of the four new compounds are reported, along with the single-crystal structure of the R = 4-Me2N–C6H4 derivative.