Coordination Compounds of Niobium(IV) Oxide Dihalides Including the Synthesis and the Crystallographic Characterization of NHC Complexes

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• 作者：Marco Bortoluzzi ; Eleonora Ferretti ; Fabio Marchetti ; Guido Pampaloni ; Calogero Pinzino ; Stefano Zacchini
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：May 2, 2016
• 年：2016
• 卷：55
• 期：9
• 页码：4173-4182
• 全文大小：633K
• 年卷期：0
• ISSN：1520-510X

文摘

The 1:1 molar reactions of NbOXb>3b> with SnBub>3b>H, in toluene at 0 °C in the presence of oxygen/nitrogen donors, resulted in the formation of NbOXb>2b>Lb>2b> (X = Cl, Lb>2b> = dme, <b>2ab>; X = Br, Lb>2b> = dme, <b>2bb>; X = Cl, L = thf, <b>2cb>; X = Cl, L = NCMe, <b>2db>; dme = 1,2-dimethoxyethane, thf = tetrahydrofuran), in good yields. The 1:2 reactions of freshly prepared <b>2db> and <b>2bb> with the bulky NHC ligands 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene, Imes, and 1,3-bis(2,6-dimethylphenyl)imidazol-2-ylidene, Ixyl, respectively, afforded the complexes NbOClb>2b>(Imes)b>2b>, <b>3b>, and NbOBrb>2b>(Ixyl)b>2b>, <b>4b>, in 50–60% yields. The reactions of <b>2bb> with NaOR, in tetrahydrofuran, gave NbOCl(OR) (R = Ph, <b>5b>; R = Me, <b>6b>) in about 60% yields. All the products were characterized by analytical and spectroscopic techniques; moreover DFT calculations were carried out in order to shed light on synthetic and structural features. Compounds <b>3b> and <b>4b>, whose molecular structures have been ascertained by X-ray diffraction, represent very rare examples of crystallographically characterized niobium–NHC systems.