Vibrational spectra of tris(dmit) complexes of main group metals: infrared, Raman and ab initio calculations

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Vol. 61; no. 11; pp. 2663 - 2676
• Main Authors: Ferreira, Glaucio Braga, Comerlato, Nadia Maria, Wardell, James Lewis, Hollauer, Eduardo
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 01.09.2005
• Subjects: Ab initio calculations; Anions - chemistry; Computational Biology; Dmit; Infrared; Metals - chemistry; Models, Molecular; Molecular Conformation; Raman; Spectrophotometry, Infrared; Spectrum Analysis, Raman; Tetraethylammonium; Toluene - analogs & derivatives; Toluene - chemistry; Vibration; Raman; Ab initio calculations; Dmit; Infrared
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2004.10.009

Infrared Fourier Transform investigation of several metal tris-complexes of 1,3-dithiole-2-thione-4,5-dithiolate (dmit) ligand have been recorded within a theoretical–experimental investigation of the vibrational molecular spectra of crystalline [NEt 4] 2[Sn(dmit) 3] and [NEt 4][Sb(dmit) 3] compounds. For the [Sn(dmit) 3] −2 anion we recorded as well the Raman Fourier Transform spectra. Ab initio calculations have been carried with several ECPs, basis sets and methodologies (RHF and DFT) in order to assess family and methodological errors precisely. Geometry optimization and subsequent hessian calculation lead to the vibration frequencies reported. These calculated frequencies and intensities assisted the fundamental, overtones and combinations bands assignments. Remarkable agreement has been found between the experimental geometries and frequencies to those here calculated. Besides the bands traditionally studied for the dmit compounds, as C C and C S stretchings, also the region below 500 cm −1 was evaluated, allowing to characterize several modes involving angular deformation of the dmit as the M S stretching of these octahedral distorted systems.