Laser (1064 nm) ablation of pressed mixtures of red phosphorus with powders of the metals cobalt or nickel generates positive ions [MPy]+ (y = 2,4,6,8) and negative ions [MxPy]-, monitored by Fourier transform ion cyclotron resonance (FTICR) mass spectrometry. At least 110 negative ions have been identified, more for Co than for Ni. The ions [MxPy]- are distributed through the range 2 ≤ x ≤ 16, 4 ≤ y ≤ 17, with [CoxP8]- (x = 2, 3, 4, 5), [CoxP10]- (x = 5, 6, 7), [NixP6]- (x = 4, 5, 7, 8), and [NixP8]- (x = 2, 3, 4, 6, 7) as more abundant ions. The best negative ion spectra are obtained with 10:1 M/P mixtures, and high laser powers. The preponderance of even numbers of P atoms suggests that P2 units are bound to the metals, and this is supported by the collisional dissociation of [MPy]+ ions (M = Co and Ni, y = 2, 4, 6) where loss of P2 is the major pathway. For both [CoP8]+ and [NiP8]+ initial loss of P4 is important. The reactions of [MP2]+, [MP4]+ and [MP8]+ with σ-ligands ammonia and methanol, and π-ligands C2H2, C2H4 and C6H6, involve addition and substitution processes.
|Number of pages||7|
|Publication status||Published - 1 Dec 1998|