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

Abstract

Este trabalho apresenta uma investigação teórico-experimental dos espectros infravermelho/ Raman de diversos metais representativos coordenados com 1,3-ditiol-2-tiona-4,5-ditiolato (dmit), a saber [NEt 4 . Os espectros IV/Raman de todos os sólidos e também o espectro IV em solução do composto [NEt 4 ] 2 [Zn(dmit) 2 ] foram registrados de 4000 a 100 cm -1 . Duas regiões foram claramente identificadas: abaixo de 380 cm -1 os modos apresentaram forte contribuição metal-ligante, e acima, os modos indicaram majoritária contribuição do ligante. Os espectros IV/Raman do NEt 4 Br também foram registrados. As bandas vibracionais foram atribuídas a partir da análise de compostos relacionados, de publicações prévias e comparadas com amplo conjunto de cálculos ab initio realizados com diversos ECPs (SBK, Sttutgart), conjunto de bases (com e sem funções d) e metodologias (RHF, DFT e MP2). As geometrias, freqüências e intensidades foram calculadas e comparadas com as freqüências experimentais visando atribuições seguras. Assim, uma excelente concordância foi obtida para diversas bandas experimentais.This work reports a theoretical-experimental investigation of the infrared/Raman vibrational spectra of several metal 1,3-dithole-2-thione-4,5-dithiolate (dmit) complexes; [NEt 4 2 ] were recorded from 4000 to 100 cm -1 . Two regions were clearly identified: below 380 cm -1 , the modes presented significant metal-ligand contributions, and above, the modes indicated major ligand contributions. IR/Raman spectra of NEt 4 Br have also been recorded. The vibrational bands have been assigned starting from the analysis of related compounds, of previous published spectra and compared to several ECPs (SBK, Stuttgart), basis sets (with and without functions d) and methodologies (RHF, MP2 and DFT). Geometries, frequencies and intensities were calculated and compared to the experimental frequencies seeking secure assignment. Thus, an excellent agreement was obtained for several experimental bands.Keywords: IR, Raman, ab initio, RHF, DFT, MP2, dmit complexes, Zn, Sb, Bi IntroductionThe syntheses and properties of metal complexes with 1,2-dithiolato-polysulfido ligands have been intensely studied 1-3 particularly since the discovery, by Cassoux and co-workers 4 in 1986, of the first metallic molecular superconductor, [TTF][Ni(dmit) 2 ] 2 , where dmit is the 1,3-dithiole-2-thione-4,5-dithiolate ligand. Presently dmit ligand complexes are the best studied.The publication of Cassoux and co-workers 4 seminal paper led a new impetus for the study of the applications of metal dmit compounds as super-conducting complexes, materials with non-linear optical properties and materials for electronic molecular devices. Such properties arise in part, from the rich redox chemistry of these compounds and the large polarizability of sulfur atoms.An additional important feature for the super-conducting property on metal bis(dmit) complexes, such as [TTF][Ni(dmit) 2 ] 2 , is the planar geometry of the anions, [3][4][5] dmit 2- Despite the large volume of wo...

Preparation and characterization of catena-[bromo(tetrahydrofuran-O)(2-thioxo-1,3-dithiole-4,5- dithiolato)antimony(III)], [Br(THF)Sb(dmit)]n

“…Among these complexes are inorganic and organometallic Sb V compounds, e.g., [Q][Sb(dmit) 3 ] (1) [4], [Q][Ar 2 Sb(dmit) 2 ] [5,6] (2) and Sb III species, such as [Q][Sb(dmit) 2 ] (3) [7][8][9][10] and PhSb(dmit)(THF) (4) [11] (Ar = Ph or p-tolyl; Q = onium cation). In contrast to the Sb V ionic complexes, 1-2, the Sb III ionic complex, 3, exhibits inter-anion Sb-S interactions: however, all the Sb centers in 1-3 are 6-coordinate, in the case of 3 excluding the Sb lone pair.…”

Crystal growth, morphology, spectrographic characterization and thermal properties of 4,5‐bis(benzoylthio)‐1,3‐dithiole‐2‐thione

“…The bands at 686.97, 677.98, 636.63 and 613.27 cm -1 are credited to CC-H out-of-plane phenyl angular deformation vibration modes. The band at 515.42 cm -1 corresponds to the symmetric stretching vibration of two carbon-sulfur single bond in the S=CS 2 fragments of dmit skeletons [19,20], and the bands at 471.31 and 455.26 cm -1 to the symmetric stretching vibration of the four carbon-sulfur single bond in the S 2 C=CS 2 fragments of dmit skeletons [21]. The observed bands along with their vibrational assignments of BBDT are summarized in table 2.…”

Preparation, single crystal growth and characterization of bis(tetrabutylammonium)bis(4,5‐dithiolato‐1,3‐dithiole‐2‐thione)copper

“…The bands with the wavenumbers of 1420, 1274 and 1236 cm -1 were identified as C=C stretching vibration of dmit. Two very intense bands at 1053 and 1030 cm -1 were assigned as C=S terminal stretching, and the bands at 1000, 923, 897, 876 and 738 cm -1 , were assigned as the stretching vibration of C-S [21]. These bands are generally used to confirm the presence of dmit ligands in complexes.…”