The heteronuclear metal carbonyl anions MNi(CO)3(-) (M = Mg, Ca, Al) have been investigated using photoelectron velocity-map imaging spectroscopy. Electron affinities of neutral MNi(CO)3 (M = Mg, Ca, Al) are measured from the photoelectron spectra to be 1.064 ± 0.063, 1.050 ± 0.064, and 1.541 ± 0.040 eV, respectively. The C-O stretching mode in these three clusters is observed and the vibrational frequency is determined to be 2049, 2000, and 2041 cm(-1) for MgNi(CO)3, CaNi(CO)3, and AlNi(CO)3, respectively. Density functional theory calculations are carried out to elucidate the geometric and electronic structures and to aid the experimental assignments. It has been found that three terminal carbonyls are preferentially bonded to the nickel atom in these heterobinuclear nickel carbonyls MNi(CO)3 (-1/0), resulting in the formation of the Ni(CO)3 motif. Ni remains the 18-electron configuration for MgNi(CO)3 and CaNi(CO)3 neutrals, but not for AlNi(CO)3. This is different from the homobinuclear nickel carbonyl Ni-Ni(CO)3 with the involvement of three bridging ligands. Present findings would be helpful for understanding CO adsorption on alloy surfaces.

Oxidation of cysteine residues constitutes an important regulatory mechanism in the function of biological systems. Much of this behavior is controlled by the specific chemical properties of the thiol side-chain...

Low-energy photoelectron imaging of HS2 (-) has been investigated, which provides the vibrational frequencies of the ground state as well as the first excited state of HS2. It allows us to determine more accurate electron affinity of HS2, 1.9080 ± 0.0018 eV. Combined with Frank-Condon simulation, the vibrational features have been unveiled related to S-S stretching and S-S-H bending modes for the ground state and S-S stretching, S-S-H bending, and S-H stretching modes for the first excited state. Photoelectron angular distributions are mainly characteristic of electron detachment from two different molecular orbitals (MOs) in HS2 (-). With the aid of accurate electron affinity value of HS2, corresponding thermochemical quantities can be accessed.