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Donor-substituted allenylidene(carbonyl)(XR 3)chromium complexes (X=P, As, Sb) – synthesis and properties

Donor-substituted allenylidene(carbonyl)(XR 3)chromium complexes (X=P, As, Sb) – synthesis and properties

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SZESNI, Normen, Bernhard WEIBERT, Helmut FISCHER, 2004. Donor-substituted allenylidene(carbonyl)(XR 3)chromium complexes (X=P, As, Sb) – synthesis and properties. In: Inorganica Chimica Acta. 357(6), pp. 1789-1798. ISSN 0020-1693. Available under: doi: 10.1016/j.ica.2003.12.013

@article{Szesni2004Donor-22920, title={Donor-substituted allenylidene(carbonyl)(XR 3)chromium complexes (X=P, As, Sb) – synthesis and properties}, year={2004}, doi={10.1016/j.ica.2003.12.013}, number={6}, volume={357}, issn={0020-1693}, journal={Inorganica Chimica Acta}, pages={1789--1798}, author={Szesni, Normen and Weibert, Bernhard and Fischer, Helmut} }

2004 Fischer, Helmut Fischer, Helmut Donor-substituted allenylidene(carbonyl)(XR 3)chromium complexes (X=P, As, Sb) – synthesis and properties Photolysis of the allenylidene pentacarbonyl chromium complexes [(CO)<sub>5</sub>Cr=C=C=C(R<sup>1</sup>)R<sup>2</sup>] (R<sup>1</sup> = NMe<sub>2</sub>, NPh<sub>2</sub>; R<sup>2</sup> = NMe<sub>2</sub>, OMe, Ph) in THF in the presence of equimolar amounts of XR<sub>3</sub>(XR<sub>3</sub> = various phosphanes, P(OMe)<sub>3</sub>, AsPh<sub>3</sub>, SbPh<sub>3</sub>) affords cis-allenylidene tetracarbonyl XR<sub>3</sub> complexes, cis-[(CO)<sub>4</sub>(XR<sub>3</sub>)Cr=C=C=C(R<sup>1</sup>)R<sup>2</sup>]. When in the photolysis of [(CO)<sub>5</sub>Cr=C=C=C(NMe<sub>2</sub>)Ph], the phosphanes PR<sub>3</sub> (R=C<sub>6</sub>H<sub>4</sub>F-p, C<sub>6</sub>H<sub>4</sub>Cl-p, OMe) are used in excess (three equivalents) two carbonyl ligands are displaced and the mer-tricarbonyl complexes mer-[(CO)<sub>3</sub>(PR<sub>3</sub>)<sub>2</sub>Cr=C=C=C(NMe<sub>2</sub>)Ph] are formed both PR3 ligands being mutually trans. The structure of the new complexes is established by IR, NMR, and UV–Vis spectroscopy, that of cis-[(CO)4(PPh3)Cr=C=C=C(NMe2)Ph] additionally by an X-ray structural analysis. As indicated by the spectroscopic data of the compounds, these complexes are best described as hybrids of allenylidene and zwitterionic alkynyl complexes with delocalization of the electron pair at nitrogen bonded to the C<sub>γ</sub> atom of the allenylidene ligand towards the metal center. The relative contribution of the allenylidene and zwitterionic alkynyl resonance forms is influenced by XR<sub>3</sub>. Increasing the donor properties of XR<sub>3</sub> favors the allenylidene resonance form. 2013-05-29T18:09:06Z eng Inorganica Chimica Acta ; 357 (2004), 6. - S. 1789-1798 Szesni, Normen 2013-05-29T18:09:06Z Weibert, Bernhard deposit-license Weibert, Bernhard Szesni, Normen

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