Structural and conformational properties of the tetrahalides MX(4) with M = S, Se, Te and X = F, Cl, Br, I were studied with quantum chemical calculations (MP2/aug-cc-pVTZ and relativistic core potentials for heavy atoms). The pseudotrigonal bipyramidal geometries (C(2v) symmetry) of the three tetrafluorides and of TeCl(4), whose structures have been determined by gas electron diffraction, are very well reproduced with this computational method. No additional stable conformer with C(3v), C(S), C(4v) or T(d) symmetry is predicted for these four chalcogen tetrahalides. For all other MX(4) compounds, except SeI(4), the existence of two conformers with C(2v) and T(d) symmetry is predicted. The T(d) structure is favoured in the case of SI(4) and SeBr(4) and SeI(4) is predicted to exist only as T(d) conformer.
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Dalton Trans
June 2024
Department of Chemistry, University of Basel, Mattenstrasse 22, 4058 Basel, Switzerland.
Group 4 Lewis acids are well-known catalysts and precursors for (non-aqueous) sol-gel chemistry. Titanium, zirconium and hafnium halides, and alkoxy halides are precursors for the controlled synthesis of nanocrystals, often in the presence of Lewis base. Here, we investigate the interaction of Lewis bases with the tetrahalides (MX, X = Cl, Br) and metal alkoxy halides (MX(OR), = 1-3, R = OPr, OBu).
View Article and Find Full Text PDFJ Phys Chem A
June 2015
†Department of Chemistry, The University of Alabama, Tuscaloosa, Alabama 35487-0336, United States.
Structures, vibrational frequencies, and heats of formation were predicted for MX4 and both singlet and triplet states of MX2 (M = group 4, group 14, Ce, and Th; X = F and Cl) using the Feller-Peterson-Dixon composite electronic structure approach based on coupled cluster CCSD(T) calculations extrapolated to the complete basis set limit with additional corrections including spin orbit effects. The spin-orbit corrections are not large but need to be included for chemical accuracy of ±1 kcal/mol. The singlet-triplet splittings were calculated for the dihalides and all compounds have singlet ground states except for the dihalides of Ti, Zr, and Ce which have triplet ground states.
View Article and Find Full Text PDFJ Phys Chem A
June 2014
Department of Chemistry, University of Wisconsin-Eau Claire, 105 Garfield Avenue, Eau Claire, Wisconsin 54702, United States.
We have conducted an extensive computational study of the structural and energetic properties of select acetonitrile-Group IV (A & B) tetrahalide complexes, both CH3CN-MX4 and (CH3CN)2-MX4 (M = Si, Ge, Ti; X = F, Cl). We have also examined the reactivity of CH3CN with SiF4, SiCl4, GeCl4, and TiCl4, and measured low-temperature IR spectra of thin films containing CH3CN with SiF4, GeCl4, or TiCl4. The six 1:1 complexes fall into two general structural classes.
View Article and Find Full Text PDFDalton Trans
March 2010
Institut für Physikalische und Theoretische Chemie, Universität Tübingen, 72076, Tübingen, Germany.
Structural and conformational properties of the tetrahalides MX(4) with M = S, Se, Te and X = F, Cl, Br, I were studied with quantum chemical calculations (MP2/aug-cc-pVTZ and relativistic core potentials for heavy atoms). The pseudotrigonal bipyramidal geometries (C(2v) symmetry) of the three tetrafluorides and of TeCl(4), whose structures have been determined by gas electron diffraction, are very well reproduced with this computational method. No additional stable conformer with C(3v), C(S), C(4v) or T(d) symmetry is predicted for these four chalcogen tetrahalides.
View Article and Find Full Text PDFDalton Trans
November 2007
School of Chemistry, University of Southampton, Southampton, UK SO17 1BJ.
Reaction of TiCl(4) or ZrI(4) with the soft, neutral o-C(6)H(4)(CH(2)EMe)(2) (E = S or Se) in anhydrous CH(2)Cl(2) (or toluene) yields the distorted octahedral chelate complexes [MX(4){o-C(6)H(4)(CH(2)EMe)(2)}]. Using Et(2)Se gives [MX(4)(Et(2)Se)(2)] (M = Zr, X = Cl or I; M = Hf, X = I). The Sn(IV) analogues, [SnCl(4){o-C(6)H(4)(CH(2)EMe)(2)}] and [SnCl(4)(Et(2)Se)(2)] were obtained similarly.
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