Electronic-absorption, Raman, and resonance-Raman spectroscopy of square-planar bis(tetraethylammonium) bis(maleonitriledithiolato)-nickelate(II), -palladate(II), and -platinate(II)

Resonance-Raman spectra of square-planar [NEt4]2[M{S2C2(CN)2}2] complexes [M = Ni, Pd, or Pt; S2C2(CN)2= maleonitriledithiolate] have been recorded with a variety of exciting lines. The results of this study together with the results obtained by low-temperature (80 K) absorption spectroscopy are combined to produce a set of assignments of the electronic transitions of these complexes in the visible region.