摘要
A boraamidinato ligand [PhB(N-2,6- i Pr 2 C 6 H 3 ) 2 ] 2− was employed to stabilize a new family of multiply bonded dimolybdenum complexes [MoCl(μ-κ 2 -PhB(N-2,6- i Pr 2 C 6 H 3 ) 2 )] 2 (4) and [Mo(μ-κ 2 -PhB(N-2,6- i Pr 2 C 6 H 3 ) 2 )] 2 n− (n=0 (5), 1 (6), 2 (7)), with the respective formal Mo−Mo bond orders of 3, 4, 4.5, and 5. Each metal center in 5–7 is two-coordinate with respect to the ligands. Of particular interest is the quadruply bonded dimolybdenum complex 5, featuring an unprecedented angular conformation. The bent Mo 2 N 4 core of 5 distorts toward planarity upon reduction. As a result, compound 7 features a planar Mo 2 N 4 core, while that of 6 is still bent but less significantly than that of 5. Additionally, the Mo−Mo bond lengths of 4–7 systematically decrease as the valency of the central Mo 2 units decreases. Complex 7 features the shortest Mo−Mo bond length (2.0106(5) Å) yet reported.