Synthesis and Hydrogenation of Heavy Homologues of Rhodium Carbynes: [(Me<sub>3</sub>P)<sub>2</sub>(Ph<sub>3</sub>P)Rh≡E‐Ar*] (E=Sn, Pb)
Max Widemann, Klaus Eichele, Hartmut Schubert, Christian P. Sindlinger, Steffen Klenner, Rainer Pöttgen, Lars Wesemann
Abstract
Abstract Tetrylidynes [(Me 3 P) 2 (Ph 3 P)Rh≡SnAr*] ( 10 ) and [(Me 3 P) 2 (Ph 3 P)Rh≡PbAr*] ( 11 ) are accessed for the first time via dehydrogenation of dihydrides [(Ph 3 P) 2 RhH 2 SnAr*] ( 3 ) and [(Ph 3 P) 2 RhH 2 PbAr*] ( 7 ) (Ar*=2,6‐Trip 2 C 6 H 3 , Trip=2,4,6‐triisopropylphenyl), respectively. Tin dihydride 3 was either synthesized in reaction of the dihydridostannate [Ar*SnH 2 ] − with [(Ph 3 P) 3 RhCl] or via reaction between hydrides [(Ph 3 P) 3 RhH] and [(Ar*SnH) 2 ]. Homologous lead hydride [(Ph 3 P) 2 RhH 2 PbAr*] ( 7 ) was synthesized analogously from [(Ph 3 P) 3 RhH] and [(Ar*PbH) 2 ]. Abstraction of hydrogen from 3 and 7 supported by styrene and trimethylphosphine addition yields tetrylidynes 10 and 11 . Stannylidyne 10 was also characterized by 119 Sn Mössbauer spectroscopy. Hydrogenation of the triple bonds at room temperature with excess H 2 gives the cis ‐dihydride [(Me 3 P) 2 (Ph 3 P)RhH 2 PbAr*] ( 12 ) and the tetrahydride [(Me 3 P) 2 (Ph 3 P)RhH 2 SnH 2 Ar*] ( 14 ). Complex 14 eliminates spontaneously one equivalent of hydrogen at room temperature to give the dihydride [(Me 3 P) 2 (Ph 3 P)RhH 2 SnAr*] ( 13 ). Hydrogen addition and elimination at stannylene tin between complexes 13 and 14 is a reversible reaction at room temperature.