An Iridium Distannylidyne - Expanding the Scope of Tetrylidyne Transition Metal Coordination Chemistry.

Although transition metal tetrylidynes have been known for several decades, analogous heavy ditetrylidynes have not been reported in the literature to this day. In this work we describe the synthesis and characterization of iridium distannylidyne [(Me3P)2Ir(SnAr*)2][WCA] (1a/1b) {[WCA] = [Al(OtBuF)4]- (1a), [BArF 4]- (1b); Ar* = 2,6-bis(2,4,6-tri-iso-propylphenyl)phenyl, tBuF = C(CF3)3, ArF = 3,5-bis(trifluoromethyl)phenyl} as the first transition metal ditetrylidyne. 1 reacts with two equivalents of CO2 to give [(Me3P)2Ir(SnAr*)2(μ3-η3-κ3-O,C,O'-CO2)2][Al(OtBuF)4] (2). In the presence of excess trimethylphosphine, trimethylsilyl azide reacts with 1 to form imido-bridged [(Me3P)3Ir(SnAr*)2(μ2-N-TMS)][BArF 4]  (3) upon extrusion of N2.