Angelika Neitzel, Tobias Ludwig, Dirk Bockfeld, Thomas Bannenberg and Matthias Tamm*,
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引用次数: 0
Abstract
The phenyl-tert-butoxysilanols Ph(tBuO)2SiOH and Ph2(tBuO)SiOH were prepared and used for the synthesis of the molybdenum 2,4,6-trimethylbenzylidyne complexes [MesC≡Mo{OSi(OtBu)2Ph}3] (1) and [MesC≡Mo{OSi(OtBu)Ph2}3] (2) from mer-[MesC≡MoBr3(dme)] (dme = dimethoxyethane, Mes = 2,4,6-trimethylphenyl). The molecular structures of 1 and 2 were determined by X-ray diffraction analysis, revealing a secondary molybdenum–oxygen interaction and a chelating κ2O,O′ coordination mode of one of the siloxide ligands in the case of 1. Treatment of 1 and 2 with an excess of 3-hexyne (EtC≡CEt) afforded the corresponding propylidyne (EtC≡Mo) complexes, which are in equilibrium with labile metallacyclobutadiene complexes as evidenced by variable-temperature NMR spectroscopy. Single crystals of [(Et3C3)Mo{OSi(OtBu)Ph2}3] (2-MCBD) have been isolated at low temperature, providing a rare example of a crystallographically characterized molybdenacyclobutadiene. The alkylidyne complexes 1 (n = 1) and 2 (n = 2) complete the series of available alkyne metathesis (pre-)catalysts [RC≡Mo{OSi(OtBu)3–nPhn}3] (n = 0–3), and their catalytic performance in the metathesis of internal and terminal alkynes was investigated and compared, if available, with the previous members of this series (n = 0, 3).
期刊介绍：
Organometallics is the flagship journal of organometallic chemistry and records progress in one of the most active fields of science, bridging organic and inorganic chemistry. The journal publishes Articles, Communications, Reviews, and Tutorials (instructional overviews) that depict research on the synthesis, structure, bonding, chemical reactivity, and reaction mechanisms for a variety of applications, including catalyst design and catalytic processes; main-group, transition-metal, and lanthanide and actinide metal chemistry; synthetic aspects of polymer science and materials science; and bioorganometallic chemistry.
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