The first experimental approach to probing frontier orbitals and HOMO–LUMO gap in bent metallocenes

Mechanism of the interaction of components in the metallocene catalytic systems containing titanium and zirconium tetracyclopentadienyls and methylaluminoxane

“…The absorption spectra of Cp 4 Zr are similar in shape to the corresponding spectra of the biscyclopentadienyl complexes [6,32]. Compared to the electronic spectra of related biscyclopentadienylzirconium dichloride Cp 2 ZrCl 2 , the absorption spectra of Cp 4 Zr are shifted to the high-energy range.…”

“…The methods of NMR [4], UV-Visible [5,7] and IR [8] spectroscopy are widely used for the determination of the structure of active species in the metallocene-and postmetallocene-based catalytic systems for olefin polymerization [4,5] and for the description of the interaction mechanism between the components of the catalytic system (in the presence of the monomer or without it) [6].…”

Photophysical Properties and Coordination Interaction of d 0 Metallocenes with Unsaturated Hydrocarbons

“…However, as follows from the photoproperties of the representative triad of π complexes Cp 2 M ( IV ) Cl 2 , their radiative lifetimes decrease manyfold in the series Ti 4+ → Zr 4+ → Hf 4+ (table). It is worth noting that this is a consequence of a considerable increase in spinorbit coupling typical for transition metal ions with open electronic subshells, i.e., for soft acids.Previously [2,4,5], we assumed that these longlived states (their experimental lifetimes are among the largest known for metal-containing molecules) are triplet. In this case, we should observe their luminescence quenching in the presence of a triplet quencher of UHCs with large S -T splitting energies.…”

“…Previously [2,4,5], we assumed that these longlived states (their experimental lifetimes are among the largest known for metal-containing molecules) are triplet. In this case, we should observe their luminescence quenching in the presence of a triplet quencher of UHCs with large S -T splitting energies.…”

“…One of the most promising approaches to an understanding of the nature and properties of frontier orbitals of organometallic π complexes of Group IVB metalsmajor components of catalysts of a large number of organic syntheses-involves generation and study of electronically excited and ground redox states of molecules [1][2][3][4][5][6]. However, fundamental processes, such as energy and electron transfer, and properties of electronically excited states of organometallic compounds have been little studied partly due to the complexity of their synthesis and of manipulations with solutions of these compounds (especially with catalytic concentrations), which are extremely sensitive to moisture and oxygen traces and to minor impurities [7].…”