Excited Electronic States and Raman Spectra of 2-Benzoylpyridine

Abstract

Raman excitation profiles of several normal modes of 2-benzoylpyridine were measured, and the structural changes encountered on excitations, excited state symmetries, and vibronic couplings among various excited electronic states of the molecule were investigated. Vibrational spectroscopic studies of the molecule were done in detail, and critical investigation on the electronic spectra of the molecule was also carried out. It is shown that the experimentally allowed transitions, corresponding to the band around 262 and 238 nm, occur to the excited states, where the major geometry changes involve both ring CC/CN and CO stretching vibrations. An excited state lying around 185 nm above the ground state was also found to play an important role in the scattering process. All necessary and valuable quantum chemical calculations accompany the presented spectral studies.

Magnetic measurements, Raman and infrared spectra of metal–ligand complex derived from $$\hbox {CoCl}_{2}\cdot \hbox {6H}_{2}\hbox {O}$$ CoCl 2 · 6H 2 O

“…The theoretically calculated structural parameters were compared with those obtained from the similar type of studies of the ligand. Bond lengths and bond angles of the phenyl and pyridyl rings are in good agreement with those found in the structure of the ligand 2-BOP [22]. The structural features of the inner sphere of the metal ion point towards a distorted octahedral symmetry of the complex with the two chlorine atoms lying on the axial line.…”

“…The structural features of the inner sphere of the metal ion point towards a distorted octahedral symmetry of the complex with the two chlorine atoms lying on the axial line. The angle between the two ring planes of the ligand in the complex is about 51 • when compared to 60 • in the free ligand [22]. The two rings are found slightly distorted and increased in size in the complex.…”

“…Firstly, the complex exhibits an overall diminution of Raman intensities with respect to the free ligand. When compared with the spectra of the free ligand [22], in the region below 600 cm −1 , the complex exhibits a number of new bands, both in the Raman and infrared spectra. Two such Raman bands are observed around 314, 326 cm −1 and these are assigned to the two ν(Co-Cl) stretching vibrations [20,25].…”

“…The infrared spectra of the complex was recorded in the region above 400 cm −1 and some of the above bands in the Raman spectra were also observed in the infrared spectra. These bands, as shown in table 2, were assigned as the Co 2+ -O/N stretching vibrations [22,25]. Some low frequency Raman bands are observed around 225 and below 200 cm −1 , which have been identified as the ligand-metal-ligand angle bending modes (table 2) [26].…”

“…Although, ν(C=O) vibration Bracketed wavenumbers -ref. [22]. *Subscript X corresponds to carbonyl carbon and nonsubscripts X and Y correspond to pyridinic nitrogen and carbonyl oxygen.…”