TRINUCLEAR NICKEL CLUSTERS, [NI-3(MU(3)-L)(MU(3)-I)(MU(2)-DPPM)3](N-,CO, CNCH3, CN-2,6-ME(2)C(6)H(3), CN-I-C3H7, CN-T-C4H9, CN-N-C4H9, NO+) AND THE DIMER OF TRIMER HEXANUCLEAR NICKEL CLUSTERS (3)](2)(MU(3),MU(3'),ETA(1),ETA(1')-CN-R-NC))(2+), (R=-(CH2)(6-), P-C6H4) - CHARACTERIZATION OF LARGE CLUSTERS BY MASS-SPECTROMETRY() (L=I)

The mass spectra of a series of trinuclear nickel clusters of the gene ral formula [Ni-3(mu(3)-L)(mu(3)-I)(mu(2)-dPPm)(3)](n+), where L = I- (1), CO (2), CNCH3 (3), CN-2,6-Me(2)C(6)H(3) (4), CN-i-C3H7 (5), CN-t- C4H9 (6), CN-n-C4H9 (7), and NO+ (8) and n = 0, 1, 2 were measured by Plasma Desorption (PD) and Fast Atom Bombardment (FAB) mass spectromet ry. Strong molecular ion peaks were observed for all of the trinuclear clusters except 8 by both techniques. Ion fragmentation followed simi lar pathways in both ionization modes. Dimers of trinuclear clusters, -3(mu(3)-I)(mu(2)-dppm)(3)](2)(mu(3),mu(3'),eta(1) eta(1')-CN-R-NC)}(2 +) where R = -(CH2)(6-) (9) and 1,4-C6H4 (10) were prepared by the rea ction of two equivalents of 1 with one equivalent of the appropriate d iisocyanide, CN-R-NC. Clusters 9 and 10 were not distinguishable from simple trimers such as 3-7 by P-31 NMR and optical spectroscopies, but were unambiguously identified by PD and FAB mass spectrometry. The pa rent ions are different for the two techniques: MI(+) in the former ca se and M(+) in the latter.