Heavy metalla vinyl-cations show metal–Lewis acid cooperativity in reaction with small molecules (NH(3), N(2)H(4), H(2)O, H(2))

Halide abstraction from tetrylidene complexes [TbbE(Br)IrH(PMe(3))(3)] [E = Ge (1), Sn (2)] and [Ar*E(Cl)IrH(PMe(3))(3)] gives the salts [TbbEIrH(PMe(3))(3)][BAr(F)(4)] [E = Ge (3), Sn (4)] and [Ar*EIrH(PMe(3))(3)][BAr(F)(4)] [E = Ge (3′), E = Sn (4′)] (Tbb = 2,6-[CH(SiMe(3))(2)](2)-4-(t-Bu)C(6)H(2), Ar* = 2,6-Trip(2)C(6)H(3), Trip = 2,4,6-triisopropylphenyl). Bonding analysis suggests their most suitable description as metalla-tetrela vinyl cations with an Ir[double bond, length as m-dash]E double bond and a near linear coordination at the Ge/Sn atoms. Cationic complexes 3 and 4 oxidatively add NH(3), N(2)H(4), H(2)O, HCl, and H(2) selectively to give: [TbbGe(NH(2))IrH(2)(PMe(3))(3)][BAr(F)(4)] (5), [TbbE(NHNH(2))IrH(2)(PMe(3))(3)][BAr(F)(4)] [E = Ge (7), Sn (8)], [TbbE(OH)IrH(2)(PMe(3))(3)][BAr(F)(4)] [E = Ge (9), Sn (10)], [TbbE(Cl)IrH(2)(PMe(3))(3)][BAr(F)(4)] [E = Ge (11a), Sn (12a)], [TbbGe(H)IrH(2)(PMe(3))(3)][BAr(F)(4)] (13), [TbbSn(μ-H(3))Ir(PMe(3))(3)][BAr(F)(4)] (14), and [TbbSn(H)IrH(2)(PMe(3))(3)][BAr(F)(4)] (15). 14 isomerizes to give 15via an 1,2-H shift reaction. Hydride addition to cation 3 gives a mixture of products [TbbGeHIrH(PMe(3))(3)] (16) and [TbbGeIrH(2)(PMe(3))(3)] (17) and a reversible 1,2-H shift between 16 and 17 was studied. In the tin case 4 the dihydride [TbbSnIrH(2)(PMe(3))(3)] (18) was isolated exclusively. The PMe(3) and PEt(3) derivatives, 18 and [TbbSnIrH(2)(PEt(3))(3)] (19), respectively, could also be synthesized in reaction of [TbbSnH(2)](−) with the respective chloride [(R(3)P)(n)IrCl] (R = Me, n = 4; R = Et, n = 3). Reaction of complex 19 with CO gives the substitution product [TbbSnIrH(2)(CO)(PEt(3))(2)] (20). Further reaction with CO results in hydrogen transfer from the iridium to the tin atom to give [TbbSnH(2)Ir(CO)(2)(PEt(3))(2)] (21). The reversibility of this ligand induced reductive elimination transferring 20 to 21 is shown.