Laser photoelectron spectrometry of Ni(CO)n-, n = 1-3

Abstract

Photoelectron spectra of the negative ions Ni(CO)"-, = 1-3, obtained with a fixed-frequency argon-ion laser operating at 488 nm are reported. The spectra provide the electron affinities for this series, EA[Ni(CO)] = 0.804 ± 0.012 eV, EA[Ni(CO)2] = 0.643 ± 0.014 eV, and EA[Ni(CO)3] = 1.077 ± 0.013 eV. The symmetric C-0 vibrational frequencies for the neutral complexes are obtained from the spectra. Metal-carbonyl bond strengths for the neutral carbonyls, Ni(CO)", = 1-4, are derived from these and other data. Electronic and geometric structure of ions and neutrals is also discussed.

Comparison of Isoelectronic Heterometallic and Homometallic Binuclear Cyclopentadienylmetal Carbonyls: The Iron–Nickel vs. the Dicobalt Systems

“…Moreover, the terminal CO group binds more tightly to iron than to nickel as reflected implicitly by the shorter Fe-CO distance in 1-2 than the Ni-CO distance in 1-3 in both the singlet and triplet states. A similar trend is noted in comparing the first metal carbonyl dissociation energies of 41 Ϯ 1 kcal/mol [47,48] in Fe(CO) 5 vs. 25 Ϯ 2 kcal/ mol [49] in Ni(CO) 4 . The 1-2Q quintet state structure is special ( Figure 4) with a non-linear Ni-Fe-CO unit (121.8°) in contrast to 1-2S and 1-2T with linear Ni-Fe-CO units.…”

Why are the Homoleptic Diyl Complexes M(InR)4 with M = Ni and Pt Stable Compounds while only Ni(CO)4 but not Pt(CO)4 can become Isolated? A Theoretical Study of M(EMe)44 and M(CO)4 (M = Ni, Pd, Pt; E = B, Al, Ga, In, Tl)

“…Complexes with the ligand CO have been prepared with all transition metal elements, but the heavier analogues of homoleptical Ni(CO) 4 with elements Pd and Pt could not become isolated so far. Pd(CO) 4 and Pt(CO) 4 have only been identified in argon matrices below 10 K [2]. The instability of the compounds comes from the weak metal-carbonyl bonds.…”

“…The instability of the compounds comes from the weak metal-carbonyl bonds. Quantum chemical studies have shown that the first bond dissociation energies (BDE) of Pd(CO) 4 and Pt(CO) 4 are very low (Ͻ 15 kcal/mol) [3]. The experimental value of the first BDE of Ni(CO) 4 is D o ϭ 25 ± 2 kcal/mol [4].…”

Probing the microhydration of metal carbonyls: a photoelectron velocity-map imaging spectroscopic and theoretical study of Ni(CO)3(H2O)n−

“…The ADE is determined to be 1.023  0.124 eV, which is in agreement with the value of 1.077  0.013 eV reported previously. 27 The vibrational frequency of Ni(CO) 3 is estimated to be 2030  320 cm -1 (Table 2), characteristic of C-O stretch, which is close to the matrix IR measurement (Table 5 2). When the second solvated H 2 O molecule is added, the VDE of Ni(CO) 3 (Table 1), respectively, which gives the ADE of 1.647  0.092 and 1.736  0.088 eV.…”