Excited-State Distortions in Bis[hydrotris(3,5-dimethyl-1-pyrazolyl)borato]copper(II) Determined from Resonance Raman Intensities and a Normal Coordinate Analysis

Abstract

Resonance Raman spectra, a normal coordinate analysis, and calculation of excited-state bond lengths and angles of bis[hydrotris(3,5-dimethyl-1-pyrazolyl)borato]copper(II) are reported. Raman spectra are obtained in resonance with a ligand field state and the lowest ligand-to-metal charge transfer (LMCT) excited state. A normal coordinate analysis is carried out using Raman and IR frequencies and resonance Raman intensities to assist in the assignment of the symmetric modes. Potential energy distributions (PED) and force constants are reported. The individual bond length changes are calculated by using the resonance Raman intensities and the PED. Bond length and angle changes throughout the entire three-dimensional skeleton are reported. The signs of the bond length changes in the pyrazolyl borate ring are interpreted in conjunction with the results of a molecular orbital calculation. The NN bond length decreases by 0.02 Å, the CN bond lengths increase by 0.05 and 0.08 Å, the Cu−N bond increases by 0.10 Å and the NBN angle decreases by 2° in the LMCT excited state.

Blue Phosphors of Dinuclear and Mononuclear Copper(I) and Silver(I) Complexes of 3,5-Bis(trifluoromethyl)pyrazolate and the Related Bis(pyrazolyl)borate

“…A vibronic progression with a constant spacing of 1270 cm -1 (±100) is observed in the emission spectra of Cu 1 and Ag 1 . The vibronic spacing is in the range of several heterocyclic ring vibrations of both ligands, i.e., the v C - N vibrations of 2,4,6-collidine and v N - N vibrations in 3,5-(CF 3 ) 2 PzH (and other reported similar pyrazolates) . The lifetime data in the microsecond scale (vide infra) suggest that the emission is phosphorescence.…”

Structural and mechanical properties of amorphous silicon carbonitride films prepared by vapor-transport chemical vapor deposition

“…It could be also assigned to the (SiH 2 ) n bending modes [21] located at around 915 cm − 1 and a-SiC:H wagging mode [29,30] centered at 990 cm − 1 . In some cases, this band is assigned to nonhydrogen Si-O stretching vibration [31]; (v) a very weak band centered at 1140 cm − 1 is believed to be due to nitrogen of N-N bond [32]. It can be also assumed that the N-N bonds are very weak due to their low binding energy E(N-N) = 1.…”

New Scorpionate Oxovanadium Complexes: Syntheses and Crystal Structures of a Series of Vanadium (IV) Complexes with Mixed Ligands of Polypyrazolylborates and Substituted Acetylacetonates

“…The medium sharp bands observed in the Ir spectrum at about 2500 cm -1 are characteristic of the b-H stretching vibration mode. bands in the range of 1600-1000 cm -1 can be attributed to pyrazolyl ring stretching modes according to a vibration study of pyrazole by Durig et al 25 a strong and sharp vibration band of the V = O stretch appears around 960 cm -1 which is close to those found in [VO(acac) {Hb(3,5-Me 2 pz) 3 }] (957 cm -1 ) 24 and [VOCl(DMF){Hb(3,5Me 2 pz) 3 }] (965 cm -1 ). 13 These values agree well with V = O frequencies generally falling in the range of 900-1000 cm -1 .…”