Preparation, Characterization, and Reactivity of Dinitrogen Molybdenum Complexes with Bis(diphenylphosphino)amine Derivative Ligands that Form a Unique 4-Membered P鈥揘鈥揚 Chelate Ring

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• 作者：Takahiko Ogawa ; Yuji Kajita ; Yuko Wasada-Tsutsui ; Hiroaki Wasada ; Hideki Masuda
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：January 7, 2013
• 年：2013
• 卷：52
• 期：1
• 页码：182-195
• 全文大小：648K
• 年卷期：v.52,no.1(January 7, 2013)
• ISSN：1520-510X

文摘

Five dinitrogen鈥搈olybdenum complexes bearing bis(diphenylphosphino)amine derivative ligands (L^R) that form a unique 4-membered P鈥揘鈥揚 chelate ring, trans-[Mo(N₂)₂(L^R)₂] (2^R: R = Ph, Xy, p-MeOPh, 3,5-iPr₂Ph, iPr), were prepared for the purpose of binding a dinitrogen molecule. The corresponding two dichloride-molybdenum complexes, trans-[MoCl₂(L^R)₂] (1^R: R = Ph, Xy), were also prepared as comparisons. FT-IR spectra of 2^R were measured and compared the 谓(N鈮) values. Moreover, X-ray crystal structure determination of 1^R (R = Ph, Xy) and 2^R (R = Xy, 3,5-iPr₂Ph) is performed. These experimental results indicated that the coordinated dinitrogen molecule gets easily influenced by the N-substitutent of diphosphinoamine ligand. In addition, to investigate the effect of the properties of the diphosphinoamine ligand for the dinitrogen molybdenum complexes, we performed DFT calculations that focused on the difference of N-substituent, the dihedral angle between P鈥揘鈥揚 plane and N-substituent aryl group, and the P鈥揘鈥揚 bite angle. This calculation revealed that the competition between the back-donation from metal to dinitrogen and that from metal to ligand was affected by P鈥揘鈥揚 bite angle and the dihedral angle of N-substituent of ligand. In order to examine the reactivity with respect to conversion of dinitrogen to ammonia, protonation and trimethylsilylation reactions of the coordinated dinitrogens were carried out for 2^R.