Mono- and Bimetallic Aluminum Alkyl, Aryl, and Hydride Complexes of a Bulky Dipyrromethene Ligand

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• 作者：Christopher G. Gianopoulos ; Kristin Kirschbaum ; Mark R. Mason
• 刊名：Organometallics
• 出版年：2014
• 出版时间：September 8, 2014
• 年：2014
• 卷：33
• 期：17
• 页码：4503-4511
• 全文大小：490K
• ISSN：1520-6041

文摘

Reactions of an appropriate organoaluminum reagent with a sterically demanding dipyrromethene (2) produced the monomeric complexes (N,N)AlR₂ (where (N,N) is deprotonated dipyrromethene; R = Me (3), ^tBu (4), Ph (5), H (6)). The alkyl and aryl derivatives 3鈥?b>5 are surprisingly stable and tolerant to exposure to air, moisture, and silica gel. Dihydride 6 is less robust and reacts with water to form the oxo-bridged aluminoxane [(N,N)AlH]₂O (7). The presence of terminal hydrides in 6 and 7 was confirmed by NMR and IR spectroscopy. Furthermore, observed Al鈥揌 stretching frequencies agree well with those predicted by DFT calculations. We also report the addition of ^tBuLi to the meso position of 2, affording 5-tert-butyl-5-phenyl-2,2鈥?dimesityldipyrromethane (8). In addition to NMR (¹H, ¹³C) and IR spectroscopy, compounds 2鈥?b>8 were further characterized by X-ray crystallography. Solid-state structures show that the aluminum and dipyrromethene ligand are nearly planar when the coligands at aluminum are slender.