Dinuclear and heteropolynuclear complexes containing Mo-2(4+) units

The quadruply bonded compound Mo-2(DpyF)(4) (1), where DpyF(-) is the anion of N,N'-di(2-pyridyl)formamidine, has been prepared by ligand substitution reactions of Mo-2(OOCCF3)(4) and either the neutral ligand, HDpyF, at ambi ent temperature or its lithium salt, LiDpyF, under refluxing conditions. An X-ray structural analysis shows that 1 has a paddlewheel structure with a Mo-Mo-4 distance of 2.1108(6) Angstrom. Reaction of 1 with CoCl2 in methano l produces the paramagnetic compound [Mo2Co(DpyF)(4)] [CoCl4]. 2MeOH (2). T he Co(II) atom in the cation [Mo-2-Co(DpyF)(4)](2+) resides on a low-spin h exacoordinate environment (S = 1/2) with a Co Mo separation of 2.979(6) A, suggesting there is no direct bonding interaction between the Co and Mo ato ms. The Mo-Mo-4 distance of 2.1096(5) Angstrom is similar to that in 1. Rea ction of 1 and CuCl in methanol yields [Mo2Cu4(DpyF)(4)Cl-2] [CuCl2](2). 2M eOH . Et2O (3). In the cation there are two copper atoms on each side of th e Mot core. Each is coordinated to two pyridyl nitrogen atoms of the cis Dp yF- ligands and loosely bridged to the other by a chloride ion. As a result , the Cu(I) atoms are not aligned with the Mo2 unit. The Cu to Mo separatio ns are in the range 3.003(1)-3.015(1) Angstrom, and the Mo-Mo distance of 2 .127(1) Angstrom is comparable to those in 1 and 2.