Ab Initio Calculations and Normal Coordinate Analysis of Ruthenium Tris-α-diimine Complexes

Abstract

For the first time, a full scaled quantum chemical normal coordinate analysis has been performed on [Ru(LL')(3)](2+) complexes, where LL' = 2,2'-bipyrazine (bpz) or 2,2'-bipyrimidine (bpm). Geometric structures were fully optimized using density functional theory and an effective core potential basis set. The infrared and Raman spectra were calculated using the optimized geometries. The results of the calculations provide a highly satisfactory fit to the experimental infrared and Raman spectra, and the potential energy distributions allow a detailed understanding of the vibrational bands therein.

Luminescent coordination polymers of 2,2′-bipyrimidine and mercury(II) salts: A structural and computational study

“…A complete vibrational assignment for 2,2-bipyrimidine has been proposed [30] and recently revised on the basis of DFT computations [31]. A normal coordinate analysis and a DFT based assignment for the coordinated bipym in the Ru(bipym) 3 3+ complex has been developed [32]. Infrared spectra are usually diagnostic of the coordination mode of the bipym ligand, especially in the 1600-1500 cm -1 region, where appear the ring stretching modes [33].…”

Adsorption of 4-Methyl-4H-1,2,4-triazole-3-thiol Molecules on Silver Nanocolloids: FT-IR, Raman, and Surface-Enhanced Raman Scattering Study Aided by Density Functional Theory

“…Vibrational spectroscopy is an important tool for molecular identification. Comparison of Raman and its complementary IR spectroscopy has enabled scientists to elucidate the structural details, protonation effects, and tautomeric preference of complex organic and inorganic molecules over the past decades. − However, proper assignments of the vibrational wavenumbers and determination of accurate force field for a molecule are of fundamental importance in vibrational spectroscopy. Recently density functional theory (DFT) is successfully utilized for the computation of vibrational frequencies and elucidation of structural details of molecules. , The most intriguing features of DFT are that everything is obtained directly from an observable and we are led to one particle theory that contains electron correlation .…”

Chemical Interactions in the Surface-Enhanced Resonance Raman Scattering of Ruthenium Polypyridyl Complexes

“…The ab initio molecular modeling of the vibrational spectra and scaled quantum mechanical normal coordinate analysis (SQM-NCA) of [Ru(bpm) 3 ] 2+ and [Ru(bpz) 3 ] 2+ have been recently reported by Alexander and Dines . Atom numbering, assignments, and descriptions of the normal modes reported herein follow those of this previous report.…”

“…Both the electronic and resonance Raman spectra of [Ru(bpm) 3 ] 2+ and [Ru(bpz) 3 ] 2+ have been well enough documented and so shall not be discussed in any great detail here. − However, given the recently published SQM-NCA extending the treatment of this class of complexes to the whole [Ru(bpm) 3 ] 2+ or [Ru(bpz) 3 ] 2+ ion rather than just a localized Ru−ligand unit, thus offering valuable symmetry information, it is perhaps useful to review the salient points. The visible region of the electronic absorption spectra of [Ru(bpm) 3 ] 2+ and [Ru(bpz) 3 ] 2+ is dominated by bands in the 20000−25000-cm -1 region, shown in Figure , which are attributed to d π → π* metal−ligand charge-transfer (MLCT) transitions of the type 1 E ← 1 A 1 and are absent in the spectra of the free ligands.…”