Chromium(II) Pincer Complexes with Dearomatized PNP and PNC Ligands: A Comparative Study of Their Catalytic Ethylene Oligomerization Activity

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• 作者：Thomas Simler ; Pierre Braunstein ; Andreas A. Danopoulos
• 刊名：Organometallics
• 出版年：2016
• 出版时间：December 27, 2016
• 年：2016
• 卷：35
• 期：24
• 页码：4044-4049
• 全文大小：401K
• ISSN：1520-6041

文摘

Monodeprotonation of the 2,6-bis(di-tert-butylphosphinomethyl) pyridine (^tBuPN^tBuP) at the α-lutidinyl-CH₂ position with 1 equiv of KCH₂C₆H₅ and concomitant dearomatization of the heterocycle afforded K(^tBuP*N_a^tBuP) (^tBuP*= di-tert-butyl vinylic P donor, ^tBuP = PtBu₂, N_a = anionic amido N donor); its transmetalation with [CrCl₂(THF)₂] afforded the Cr^II complex [Cr(^tBuP*N_a^tBuP)Cl] (A). The X-ray diffraction analysis of A established a slightly distorted square-planar coordination geometry at the metal center and confirmed retention of the dearomatized coordinated ligand. The catalytic activity of A in ethylene oligomerization was studied and compared with that of the related Cr^II complexes [Cr(^tBuP*N_aC^NHC)Cl] (B) and [Cr{Cr(^tBuP*N_a^tBuP*)Cl}₂] (C) previously reported [ Chem. Commun., 2015, 51, 10699 and Dalton Trans., 2016, 45, 2800, respectively].