Resonance Raman and time-resolved resonance Raman studies of complexes of divalent ruthenium with bipyridine and 4,4′-bipyrimidine ligands

Abstract

Resonance Raman (RR) and time-resolved resonance Raman (TR3) spectra are reported for the complexes of divalent ruthenium with the ligands 4,4º-bipyrimidine (bpm) and 2,2º-bipyridine (bpy), i.e. and Ru(bpm) 3 2' Ground-state RR studies of the latter employing excitation with radiation of 413.1, 457.9 and Ru(bpy) 2 (bpm)2'. 514.5 nm permit the assignment of an electronic absorption band maximizing at 428.5 nm to a Ru(II)-to-bpy charge-transfer transition, while the band maximum at 516.0 nm is assigned to the Ru(II)-to-bpm charge-transfer band. The TR3 studies employing the 354.7 nm harmonic of a 10 ns pulsed Nd : YAG laser provide deÐnitive evidence for selective population of the bpm-localized excited state for the heteroleptic complex Ru(bpy) 2 (bpm)2'.

Chromophore-specific theoretical spectroscopy: From subsystem density functional theory to mode-specific vibrational spectroscopy

“…Resonance Raman spectroscopy is often applied in studies on motifs of artificial or biological photosystems [461,462], like bacteriochlorophyll a [463] or dendritic antenna systems [464], where electron-or excitation-energy transfer processes occur between different chromophores in a functional arrangement. It has also been used to investigate the spectroscopic properties of ruthenium-polypyridyl or related complexes [465] (see also Section 6.4).…”

Revealing the chromophoric composition of multichromophoric polypyridyl complexes of Re(I) and Os(II): a resonance Raman study

“…The enhancement of a carbonyl mode of different symmetry 9 from that enhanced with transition A.1 suggests that a different metal donor orbital is involved. Similarly, the enhancement of a different set of dpqMe 2 vibrations is consistent with charge transfer into a different dpqMe 2 Ł molecular orbital 6,20,23. This transition is labelled A.2.…”

“…Similarly, the enhancement of a different set of dpqMe 2 vibrations is consistent with charge transfer into a different dpqMe 2 Ł molecular orbital. 6,20,23 This transition is labelled A.2. Finally, bands at 1600, 1491, 1474 and 1327 cm 1 are enhanced by 413.1 nm excitation.…”

“…1 -4 A method of assigning spectral features to chromophores present under such a broad absorption envelope is resonance Raman spectroscopy. 5,6 The resonance Raman effect enhances the intensities of vibrational bands associated with a chromophore that absorbs at the excitation laser wavelength. 7,8 The aim of this work was to establish the wavelengths and assignments of electronic transitions undergone by some binuclear metal complexes.…”

Heteroleptic ruthenium(II) complexes based on 6,6′-disubstituted 4,4′-bipyrimidines: New room temperature red-emitting species

“…Thus, the replacement of one of the bipyridine ligands by a diazine offers the possibility of tuning the redox and photophysical properties of the complexes. Ruthenium(II) complexes based on 3,3 0 -bipyridazine [12], 2,2 0 -bipyrazine [13], 2,2 0 -bipyrimidine [14], and 4,4 0 -bipyrimidine [15] have been described in connection with their incorporation into solar energy conversion devices. However, among all these diazines and their complexes, relatively little attention has been given to the complexes bearing the 4,4 0 -bipyrimidine ligand (bpm) [16,17].…”