Synthesis and Hydrogenation of Heavy Homologues of Rhodium Carbynes: [(Me(3)P)(2)(Ph(3)P)Rh≡E‐Ar*] (E=Sn, Pb)

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 [Formula: see text] [(Ar*SnH)(2)]. Homologous lead hydride [(Ph(3)P)(2)RhH(2)PbAr*] (7) was synthesized analogously from [(Ph(3)P)(3)RhH] and [Formula: see text] [(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.