Synthesis and Structural Characterization of Divalent Transition Metal Alkynylamidinate Complexes |
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| Authors: | Dr Sida Wang Dr Phil Liebing Dr Martin Feneberg Prof Farid M Sroor Dr Felix Engelhardt Dr Liane Hilfert Dr Sabine Busse Elias Kluth Prof?Dr Rüdiger Goldhahn Prof?Dr Frank T Edelmann |
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| Institution: | 1. Institut für Chemie, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106 Magdeburg, Germany;2. Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, Humboldtstr. 8, 07743 Jena, Germany;3. Institut für Physik, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106 Magdeburg, Germany;4. Organometallic and Organometalloid Chemistry Department, National Research Centre, Cairo, 12622 Egypt |
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| Abstract: | A series of new alkynylamidinate complexes of selected first and second row transition metals has been synthesized and fully characterized. Treatment of MCl2 precursors (M=Mn, Fe, Co) with 2 equiv. of the lithium alkynylamidinates Lic-C3H5?C≡C?C(NR′)2] ? THF (R′=iPr (2), Cy (cyclohexyl) ( 2 )) afforded a series of binuclear complexes of the type M2c-C3H5?C≡C?C(NR)2-κN:κN′]2c-C3H5?C≡C?C(NR)2-κ2N,N′]2 ( 3 : M=Mn, R=Cy; 4 a : M=Fe, R=iPr; 4 b : M=Fe, R=Cy; 5 : M=Co, R=iPr) with no significant metal-metal bonding. In marked contrast, a similar reaction of CrCl2 with 2 equiv. of 1 afforded the homoleptic dinuclear chromium(II) complex Cr2c-C3H5?C≡C?C(NiPr)2-κN:κN′]4 ( 6 ) which supposedly comprises a Cr?Cr quadruple bond. Complex 6 could also be prepared in a more rational way and in better yield (61 %) by using dichromium(II) tetraacetate, Cr2(OAc)4, as starting material. Related reactions employing dimolybdenum(II) tetraacetate, Mo2(OAc)4, and 2 or 3 equiv. of 1 afforded the mixed-ligand paddle wheel-type complexes trans-Mo2(OAc-κO:κO′)2(c-C3H5?C≡C?C(NiPr)2-κN:κN′]2 ( 7 ) and Mo2(OAc-κO:κO′)(c-C3H5?C≡C?C(NiPr)2-κN:κN′]3 ( 8 ). All title compounds were structurally characterized through single-crystal X-ray diffraction and spectroscopic techniques (NMR, IR, Raman). |
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| Keywords: | alkynylamidinate amidinate lithium multiple bonds transition metal X-ray diffraction |
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