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Infrared, Raman and resonance Raman spectra of the solid nickel(II) thiophosphate compound (PPh 4 ) 3 [(NiPS 4 ) 3 ] and force constants in the trinickel [Ni 3 P 3 S 12 ] 3− cyclic anion
Author(s) -
Sourisseau C.,
Rodriguez V.,
Jobic S.,
Brec R.
Publication year - 1999
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/(sici)1097-4555(199912)30:12<1087::aid-jrs489>3.0.co;2-i
Subject(s) - raman spectroscopy , chemistry , thiophosphate , infrared , ion , valence (chemistry) , resonance (particle physics) , analytical chemistry (journal) , infrared spectroscopy , crystallography , molecular physics , atomic physics , physics , organic chemistry , optics , chromatography
The UV–visible (350–900 nm), infrared and Raman (30–800 cm −1 ) spectra of a new transition metal thiophosphate solid compound, (PPh 4 ) 3 [(NiPS 4 ) 3 ], were analyzed using powder samples. Electronic transitions of the 1 F 2 ← 1 A 1 type originating in the (PS 4 ) 3− groups were detected from visible absorbance measurements in the 440–520 nm range and most of the expected infrared and Raman vibrational modes of the trimetallic ring anion [Ni 3 P 3 S 12 ] 3− were observed in the 600–30 cm −1 region. Also, resonance Raman spectra were recorded using exciting radiation of several wavelengths in the 680–450 nm range and the Raman excitation profiles of several fundamentals were established: they all peak near 488 nm and exhibit the strongest enhancements for totally symmetric and non‐totally symmetric stretching and bending modes of (NiS 4 ) groups. It is therefore concluded that several ligand to metal charge‐transfer electronic transitions are overlapped and involved in vibronic coupling mechanisms. Furthermore, the vibrational assignments were checked by a valence force field calculation for an isolated [Ni 3 P 3 S 12 ] 3− anion of C 3 v symmetry. The potential energy distributions and mean squared vibrational amplitudes revealed strong ν(Ni–S) and δ(S–P–S) couplings and relatively high ν(Ni–S) stretching modes at near 310 cm −1 . Compared with results in the one‐dimensional KNiPS 4 compound containing infinite anionic chains ∞1 [NiPS 4 ] − , one notes a force constant increase on the P—S exocyclic ( µ 1 ) bonds, no change on the bridged ( µ 2 and µ 3 ) P—S bonds and a slight increase in the Ni–S stretching force constants varying from 75 to 85 N m −1 in accordance with a localized ligand to metal charge‐transfer mechanism. Hence a comparison of the induced Raman scattering processes in the (PPh 4 ) 3 [(NiPS 4 ) 3 ] and KNiPS 4 solid compounds shows that the ligand to metal charge transfers and the crystal field effects have a strong influence on the vibrational properties in these thiophosphate compounds. Copyright © 1999 John Wiley & Sons, Ltd.