Photoelectron Velocity Map Imaging Spectroscopy of Lead Tetracarbonyl–Iron Anion PbFe(CO)₄^–

Abstract

Joint research of photoelectron velocity map imaging spectroscopy and density functional theory has been performed to probe the geometrical structures and electronic properties for heterodinuclear iron-lead carbonyl cluster PbFe(CO)4(-), which serves as a monomer of the metal-metal bonded oligomer. The photoelectron detachment of PbFe(CO)4(-) is recorded at two different photon energies with rich spectral features. The ground-state transition obtained at 532 nm reveals a broad vibrationally resolved spectral band, which corresponds to the lead-iron stretching, while the 355 nm spectrum displays many more transitions on the higher-energy side, which correspond to the electronic excited states of PbFe(CO)4. Theoretical calculations at the B3LYP level are performed to explore the ground states of both the anionic and neutral PbFe(CO)4 and to support spectral identification of the fine resolved photoelectron spectra. Moreover, the unique chemical bonding between lead and iron in PbFe(CO)4 is discussed with the aid of natural bond orbital analyses.

Infrared Photodissociation Spectroscopy of Heterodinuclear Iron–Zinc and Cobalt–Zinc Carbonyl Cation Complexes

“…In both spectra, the most intense peaks are saturated coordinated homoleptic mono- and dinuclear iron and cobalt carbonyl cation complexes, including Fe­(CO) 5 + , Co­(CO) 5 + , Fe 2 (CO) 8 + , and Co 2 (CO) 8 + , which have been studied by infrared photodissociation spectroscopy previously. − It is interesting to note that homoleptic zinc carbonyl complexes are barely observed. As discussed previously, − the preferred formation of iron and cobalt carbonyls over the zinc carbonyls suggests that the iron– and cobalt–carbonyl bond strengths are larger than that of zinc. Besides the homoleptic carbonyls, heteronuclear carbonyl complexes with chemical formulas of FeZn­(CO) 5 + and CoZn­(CO) 7 + are also observed with appreciable peak intensities.…”

Ligand-Enhanced CO Activation by the Early Lanthanide–Nickel Heterodimers: Photoelectron Velocity-Map Imaging Spectroscopy of LnNi(CO)n– (Ln = La, Ce)

“…It can be seen from the above structural analysis of the heterobinuclear LnNi­(CO) n – (Ln = La, Ce) carbonyls that the number of extremely activated CO molecule is increased in the larger clusters ( n ≥ 4), evidencing the ligand-enhanced CO activation by the early lanthanide-nickel heterodimers. This is different from the structural evolutions of other homobinuclear, heterobinuclear metal–iron, and metal–nickel carbonyls. − In the Ti 2 (CO) n – ( n = 1–9) clusters, the building block of three side-on-bonded CO molecules is favored for n = 3–5, whereas the motif of two side-on-bonded CO molecules is preferred for n = 6–9, indicating that the number of extremely activated CO molecule is reduced in the larger clusters . In the MNi­(CO) n – (M = Ti, Zr, Hf) complexes, the n = 3 cluster is comprised of one terminal, one bridging, and one side-on-bonded carbonyl, whereas the binding motif of three bridging carbonyls is preferred in n = 4–7, also suggesting that the degree of CO activation is reduced in the larger clusters …”

“…Recently, the study on the reaction of CO with heteronuclear metal clusters has aroused increasing attention, which helps uncover the diverse structural features, the nature of chemical bonding, and the synergy effects of different transition metals on the catalytic performance. − In the heterobinuclear metal–iron carbonyls, PbFe­(CO) 4 – and CuFe­(CO) 4 – , the CO ligands are terminally bonded to the iron atom. , The MFe­(CO) 8 + (M = Co, Ni, Cu) cations are comprised of eclipsed (CO) 5 Fe–M­(CO) 3 + motif and MCu­(CO) 7 + (M = Co, Ni) consist of staggered (CO) 4 M–Cu­(CO) 3 + motif, where the CO molecules are terminally coordinated to the metal atoms . The ZnFe­(CO) 5 + carbonyl consists of a Zn–Fe­(CO) 5 structure with a Zn–Fe half bond and ZnCo­(CO) 7 + has a staggered Zn­(CO) 3 –Co­(CO) 4 structure involving a Zn–Co σ single bond .…”

Theoretical study of CO adsorption on FexCuy (x + y = 3) clusters and reactive activity of their carbonyl complexes

“…Practically carbonyl complexes consist of not only homonuclear carbonyl but also included heteronuclear carbonyl such as CuNi(CO) n 0/1− (n = 1-4), MNi(CO) 7 − (M = V, Nb, Ta), CuFe(CO) n − (n = 4-7) and PbFe(CO) 4 − [14][15][16][17]. The most unsaturated neutral species apparently have been studied focus on the one carbon monoxide on clusters [18][19][20].…”