Synthesis and Reactivity of the 13-Vertex Metallacarborane Anions [4,4,4-(CO)₃-<i>c</i><i>loso</i>-4,1,6-MC₂B₁₀H₁₂]^- (M = Re, Mn)

Reaction of Na2[nido-7,9-C2B10H12] with either [ReBr(CO)3(THF)2] or [Mn(NCMe)3(CO)3][PF6] in THF (THF = tetrahydrofuran), followed by introduction of [N(PPh3)2]Cl, affords the 13-vertex monoanionic metallacarboranes [N(PPh3)2][4,4,4-(CO)3-closo-4,1,6-MC2B10H12] (M = Re (2a), Mn (2b), respectively). Treatment of 2a with I2 results in iodide substitution at a cage {BH} vertex to form [N(PPh3)2][4,4,4-(CO)3-7-I-closo-4,1,6-ReC2B10H11] (3), which, upon reaction with MeMgBr, gives the methylated derivative [N(PPh3)2][4,4,4-(CO)3-7-Me-closo-4,1,6-ReC2B10H11] (4). Treatment of 2a with [NO][BF4] in CH2Cl2 forms two species, [4,4-(CO)2-4-NO-7-X-closo-4,1,6-ReC2B10H11] (X = H (5), Cl (6)). Bimetallic compounds are formed upon treatment of 2a with 1 molar equiv of the cations {M‘(PPh3)}+, namely, the zwitterionic species [4,4,4-(CO)3-4,7-{M‘(PPh3)}-7-(μ-H)-closo-4,1,6-ReC2B10H11] (M‘ = Cu (7), Au (8)). A novel, dicopper species, [4-PPh3-4,7,10-{Cu(PPh3)}-7,10-(μ-H)2-closo-4,1,6-CuC2B10H10] (9), has been isolated during the synthesis of 7.