A series of novel hexacoordinate silicon(IV) complexes with an SiO2N4 skeleton (compounds (OC-6-12)-3, (OC-6-12)-4, (OC-6-12)-5, (OC-6-12)-6, and (OC-6-2'2)-7) were synthesized, starting from Si(NCO)4 or Si(NCS)4. These compounds contain (i) two bidentate O,N-chelate ligands (or one tetradentate O,N,N,O-chelate ligand) derived from 4-aminopent-3-en-2-ones of the formula type Me-C(NRH)=CH-C(O)-Me (R = organyl) and (ii) two monodentate cyanato-N or thiocyanato-N ligands. Formally, the bidentate singly negatively charged O,N-chelate ligands (tetradentate 2-fold negatively charged O,N,N,O-chelate ligand) behave as ligands of the imino-enolato type. In addition, the adduct trans-8 was synthesized by reaction of Si(NCS)4 with 2 molar equiv of Me-C(Ni-PrH)=CH-C(O)-Me. This hexacoordinate silicon(IV) complex contains (i) four monodentate thiocyanato-N ligands and (ii) two neutral monodentate ligands of the iminio-enolato type. All compounds synthesized were structurally characterized by single-crystal X-ray diffraction and solid-state and solution NMR spectroscopy. To get more information about the stereochemistry of these compounds, the experimental investigations were complemented by computational studies.
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http://dx.doi.org/10.1021/ic0485211 | DOI Listing |
Dalton Trans
October 2011
Universität Würzburg, Institut für Anorganische Chemie, Germany.
The neutral pentacoordinate monoamidinatosilicon(IV) complex 1 (SiN(2)Cl(3) skeleton) and the neutral hexacoordinate monoamidinatosilicon(IV) complexes 2-9 (SiN(3)OF(2), SiN(3)OCl(2), SiN(3)OBr(2), SiN(5)O and SiN(3)O(3) skeletons) were synthesised and characterised by elemental analyses, single-crystal X-ray diffraction (except for 1) and NMR spectroscopy in the solid state and in solution. Compounds 2-9 contain one bidentate monoanionic N,N'-diisopropylbenzamidinato ligand, one bidentate monoanionic ligand derived from 8-hydroxyquinoline and (i) two identical monoanionic ligands (F, Cl, Br, N(3), NCO, NCS, OSO(2)CF(3)) or (ii) one bidentate dianionic benzene-1,2-diolato ligand. The dynamic behavior of 2-4 (SiN(3)OX(2) skeleton; X = F, Cl, Br) and 9 (SiN(3)O(3)) in solution was studied by multinuclear variable-temperature NMR experiments.
View Article and Find Full Text PDFDalton Trans
October 2010
Universität Würzburg, Institut für Anorganische Chemie, Am Hubland, D-97074, Würzburg, Germany.
The novel neutral hexacoordinate bis(benzamidinato)silicon(iv) complexes 1-10 (SiN(4)X(2) skeletons; X = F, Cl, Br, C, N, S, Se) were synthesised and characterised by elemental analyses, single-crystal X-ray diffraction (except for 2) and NMR spectroscopy in the solid state and in solution. The dynamic behavior of 1 (SiN(4)Cl(2) skeleton) and 3 (SiN(4)F(2)) was additionally studied by variable-temperature NMR experiments. Compounds 1 and 2 (SiN(4)Br(2)) were obtained by reaction of SiCl(4) and SiBr(4), respectively, with two molar equivalents of the corresponding lithium amidinate.
View Article and Find Full Text PDFChemistry
June 2010
Universität Würzburg, Institut für Anorganische Chemie, Am Hubland, 97074 Würzburg, Germany.
The neutral hexacoordinate silicon(IV) complex 6 (SiO(2)N(4) skeleton) and the neutral pentacoordinate silicon(IV) complexes 7-11 (SiO(2)N(2)C skeletons) were synthesized from Si(NCO)(4) and RSi(NCO)(3) (R = Me, Ph), respectively. The compounds were structurally characterized by solid-state NMR spectroscopy (6-11), solution NMR spectroscopy (6 and 10), and single-crystal X-ray diffraction (8 and 11 were studied as the solvates 8 x CH(3)CN and 11 x C(5)H(12) x 0.5 CH(3)CN, respectively).
View Article and Find Full Text PDFInorg Chem
May 2009
Departamento de Química, Universidad de Guanajuato, Noria Alta s/n, Guanajuato, Gto. 36050, Mexico.
Chem Asian J
April 2009
Institut für Anorganische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
A series of novel neutral hexacoordinate silicon(IV) complexes with SiO(2)N(4) skeletons (compounds 4-8) was synthesized and structurally characterized by single-crystal X-ray diffraction and solid-state NMR spectroscopy ((13)C, (15)N, (29)Si). The silicon(IV) complexes each contain two bidentate monoanionic O,N Schiff base ligands and two cyanato-N or thiocyanato-N ligands. Compounds 4-8 were prepared from Si(NCO)(4) or Si(NCS)(4), whereby the complex formation involved some unexpected chemical transformations of the ligands.
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