Infrared spectroscopic studies of transition metal complexes and polarizability effect

Mössbauer parameters of organometallic compounds and polarizability effect

“…By now it has become clear that the polarizability effect, first observed in studies of ionic gas-phase reactions [55,56], influences the diversified physical properties P such as the ionization potentials [59,60,71], electron affinities [63], core-electron binding energies [70,71], potentials of electrochemical oxidation [64] and reduction [65], spectroscopic and thermodynamical characteristics of radical ions [73], H-complexes [61], chargeetransfer complexes [58], atranes [62,66], transition metal complexes [68,69,72] and other donor-acceptor complexes [61].…”

“…In two series (III and XIX) the contribution Pol is larger than the sum of the contributions Ind and Res. In specific series the examples of very significant contributions Pol (in brackets) are found in studies of such properties P as the ionization potentials of N-centred radical cations (55%, gaseous state) [71], frequencies in the IR spectra of transition metal complexes (57%, solution) [72], transition metal NMR chemical shifts (86%, solution) [69], EPR parameters of radical ions (92%, solution) [73], coreelectron binding energies of organoelement compounds (56%, solid state) [70], NQR parameters of complexes (75%, solid state) [79] as well as in this work (57%, solid state). As is easy to see, the contributions Ind, Res, and Pol are interdependent.…”

“…In these complexes the interaction of atom Fe with the ligands proceeds by a donoracceptor as well as dative mechanism, resulting in the partial charge q on Fe; for more details, see e.g [81]. Previously in transition metal complexes the polarizability effect has been established using IR [68,72], NMR [69], and EPR [73] spectroscopy.…”

Reactivity of organometallic compounds and polarizability effect

“…As a consequence the delocalization of the partial charge q and the arising of charge density on ring take place. The result of delocalization can be conceived as a decrease of the distance between X and R c q , causing the polarizability effect to arise [31,32,34,38]. Therefore the charged non-classic narrow series 4-XC 6 H 4 R c q obey Eq.…”

“…The first evidence for this effect has come from the study of ionic gas-phase reactions involving simple organic molecules [28e30]. Further investigations demonstrated that the polarizability effect has a profound influence on the parameters of the IR [31], NMR [32,33], EPR [34], NQR [35], UVeVis electronic [36], ultraviolet photoelectron [37,38], X-ray photoelectron [39], and Mossbauer [40] spectra as well as on the bond lengths [41] and toxicity [42] of organometallic compounds. A necessary condition for arising this effect is initiation of the partial charge q on M atom and/or on bonds MÀB and MÀL.…”