The new enneanuclear nickel carbonyl anion [Ni9(CO)16]2− and its relationships with the [Ni12(CO)21]4− and [Ni6Rh3(CO)17]3− clusters

The reaction of [N(PPh3)(2)](2)[Ni-6(CO)(12)] with Cu(PPh3)(x) Cl (x = 1, 2). as well as the degradation of [N(PPh3)(2)](2)[H2Ni12(CO)(21)] with PPh3, affords the new and unstable dark orange-brown [N(PPh3)(2)](2)[Ni-9(CO)(16)]. THF salt in low yields. This salt has been characterized by a CCD X-ray diffraction determination, along with IR spectroscopy and elemental analysis. The close-packed two-layer metal core geometry of the [Ni-9(CO)(16)](2) dianion is directly related to that of the bimetallic [Ni6Rh3(CO)(17)](3-) trianion and may be envisioned to be formally derived from the hcp three-layer geometry of [Ni-12(CO)(21)](4-) by the substitution of one of the two outer [Ni-3(CO)(3)(mu - CO)(3)](2-) layers with a face-bridging carbonyl group. (C) 2002 Elsevier Science B.V. All rights reserved.