Nickel(II) carbonyl, ammonia, and aceto-nitrile complexes supported by a pyridine dipyrrolide pincer ligand.

The synthesis, isolation and crystal structures of nickel(II) carbonyl, aceto-nitrile and ammonia complexes supported by a dianionic, pyridine dipyrrolide pincer ligand [pyrr(2)py](2-), namely, carbonyl[2,2'-(pyridine-2,6-di-yl)bis-(3,5-di-p-tolyl-pyrrolido-κN)]-nickel(II), [Ni(C(41)H(33)N(3))(CO)], ammine[2,2'-(pyridine-2,6-di-yl)bis-(3,5-di-p-tolyl-pyrrolido-κN)]nickel(II), [Ni(C(41)H(33)N(3))(NH(3))], and (aceto-nitrile-κN)[2,2'-(pyridine-2,6-di-yl)bis-(3,5-di-p-tolyl-pyrrolido-κN)]nickel(II), [Ni(C(41)H(33)N(3))(CH(3)CN)], as well as the free ligand 2,6-bis-(3,5-di-p-tolyl-pyrrol-2-yl)pyridine, C(41)H(35)N(3) or [pyrr(2)py]H(2) are reported. The nickel complexes are four-coordinate and adopt a square-planar geometry. The CO stretch of the nickel-bound carbon monoxide ligand of [pyrr(2)py]Ni(CO) has been observed at 2101†cm(-1). The ammonia and aceto-nitrile complexes, [pyrr(2)py]Ni(NH(3)) and [pyrr(2)py]Ni(NCMe) feature all-nitro-gen coordination spheres around nickel consisting of different N-donor ligand types.