Redox-Initiated Reactivity of Dinuclear β-Diketiminatoniobium Imido Complexes

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• 作者：Benjamin M. KriegelLara C. E. Naested ; Grégory Nocton ; K. V. Lakshmi ; Trevor D. Lohrey ; Robert G. BergmanJohn Arnold
• 刊名：Inorganic Chemistry
• 出版年：2017
• 出版时间：February 6, 2017
• 年：2017
• 卷：56
• 期：3
• 页码：1626-1637
• 全文大小：670K
• ISSN：1520-510X

文摘

High-valent dichloride and dimethylniobium complexes 1 and 2 bearing tert-butylimido and N,N′-bis(2,4,6-trimethylphenyl)-β-diketiminate (BDI^Ar) ligands were prepared. The dimethyl complex reacted with dihydrogen to release methane and generate the hydride-bridged diniobium(IV) complex 3 in high yield. One-electron oxidation of 3 with silver salts resulted in the release of dihydrogen and conversion to a mixed-valent Nb^III–Nb^IV complex, 4, that displayed a frozen-solution X-band electron paramagnetic resonance signal consistent with a slight dissymmetry between the two Nb centers. Spectroscopic and computational analysis supported the presence of Nb–Nb σ-bonding interactions in both 3 and 4. Finally, one-electron reduction of 4 resulted in conversion to the highly dissymmetric Nb^V–Nb^V dimer 5 that formed from the reductive C–N bond cleavage of one of the BDI^Ar supporting ligands.