Synthesis of the manganese-monocarbollide dianion [1-NHBut-2,2,2-(CO)3-closo-2,1-MnCB10H10]2−: Reactions with transition metal cations

Abstract Reaction of [Mn(NCMe) 3 (CO) 3 ][PF 6 ] with Li 3 [7-NHBu t - nido -7-CB 10 H 10 ] in THF (THF = tetrahydrofuran) affords the twelve-vertex manganacarborane dianion [1-NHBu t -2,2,2-(CO) 3 - closo -2,1-MnCB 10 H 10 ] 2− , isolated as the bis-[N(PPh 3 ) 2 ] + salt ( 5a ). This species reacts with {Pt(dppe)} 2+ (dppe = Ph 2 PCH 2 CH 2 PPh 2 ) to afford the bimetallic complex [1-NH 2 Bu t -2,3-{Pt(dppe)}-2,2,2-(CO) 3 - closo -2,1-MnCB 10 H 9 ] ( 7 ) which has an Mn–Pt bond. In contrast, with {Cu(PPh 3 )} + the anion of 5a yields a CuMnCu trimetallic compound [1-{NH(Bu t )Cu(PPh 3 )}-2,3,7-{Cu(PPh 3 )}-3,7-(μ-H) 2 -2,2,2-(CO) 3 - closo -2,1-MnCB 10 H 8 ] ( 8 ) in which one of the Cu centers is bonded to Mn, whilst the other is attached to the pendant NHBu t group. Upon treatment with Ag + , compound 5a is oxidized giving the very unusual Mn(III)-carbonyl complex [1,2-μ-NHBu t -2,2,2-(CO) 3 - closo -2,1-MnCB 10 H 10 ] ( 9a ) in which the carborane ligand formally acts as an eight-electron donor to manganese. The novel structural features of compounds 7 , 8 , and 9a have been confirmed by X-ray diffraction studies.