Photochemistry and reaction intermediates of the bimetallic Group VIII cyclopentadienyl metal carbonyl compounds, (η5-C5H5)2M2(CO)4 and their derivatives

Structure, Spectroscopy and Photochemistry of the [M(η5-C5H5)(CO)2]2 Complexes (M=Fe, Ru)

“…The LUMO orbital is a s * metal-metal orbital. Calculations using other theoretical models like extended Hückel [9,28,29], Hartree-Fock [30,31], Fenske-Hall [32,33] and DFT [2] show similar pattern of the HOMO-LUMO orbitals. The s metal-metal orbital (HOMO-5, denoted further as s) is placed low and the orbital contour between two metal atoms is rather small, which indicates that direct metal-metal bond in the bridged Fe-complex is quite weak.…”

“…The theoretical interest in the [M(h 5 -C 5 H 5 )(CO) 2 ] 2 dimers concerns mostly their versatile structures which entail varied thermal and photochemical behaviour [1,2]. The versatility is reflected by the structural changes accompanying crystal dissolution or a change of solvent [2].…”

“…The versatility is reflected by the structural changes accompanying crystal dissolution or a change of solvent [2]. The behaviour is dependent on the central atom nature: the iron and ruthenium dimers crystallize mostly in the bridged forms, [M(h 5 -C 5 H 5 )(µ-CO)(CO)] 2 , distinct from the osmium compound, which forms only the non-bridged dimer.…”

Investigation of organometallic reaction mechanisms with one and two dimensional vibrational spectroscopy

“…Electronic excitation typically results in the population of metal-ligand anti-bonding orbitals, and in the case of metal carbonyl complexes, causes dissociation of a CO ligand [28]. For the transition-metal dimers discussed in Chapters 3-5, visible photoexcitation populates the metal-metal anti-bonding orbitals, causing dissolution of the metal-metal bond and formation of two metal-centered radicals [29,30].…”

“…This final product was formed by dimerization of the monocarbonyl 17e radicals CpFe(CO)P(OMe) 3 . Although irradiation primarily results in homolysis of the Fe-Fe bond, for short wavelength excitation it also causes photodissociation of a CO ligand from the complex [29]. We focus on the reactions of the metal-centered radicals.…”