B−C Bond Cleavage of BArF Anion Upon Oxidation of Rhodium(I) with AgBArF. Phosphinite Rhodium(I), Rhodium(II), and Rhodium(III) Pincer Complexes

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• 作者：Hiyam Salem ; Linda J. W. Shimon ; Gregory Leitus ; Lev Weiner ; David Milstein
• 刊名：Organometallics
• 出版年：2008
• 出版时间：May 26, 2008
• 年：2008
• 卷：27
• 期：10
• 页码：2293 - 2299
• 全文大小：261K
• 年卷期：v.27,no.10(May 26, 2008)
• ISSN：1520-6041

文摘

A rare case of BAr_F anion cleavage (BAr_F⁻ = tetrakis(3,5-bis(trifluoromethyl)phenyl)borate) by a metal complex is described. Reaction of the Rh(I) dinitrogen complexes 5a,b and 6a,b, based on the phosphinite pincer ligands {C₆H₄[OP(^tBu)₂]₂} (2), with 2 equiv of AgBAr_F at room temperature resulted in B−C bond cleavage of one of the BAr_F anions and aryl transfer to afford the Rh(III) aryl complexes 7 and 8, respectively. The X-ray structure of 8 revealed a square-pyramidal geometry with a coordinated acetone molecule. The aryl transfer occurred as a result of electrophilic attack by unsaturated Rh(III) on one of the aryl rings of the BAr_F anion. Utilizing different solvents yielded the same product, except when CH₃CN was used, in which case one-electron oxidation took place, yielding complex 9. Treatment of 6a,b with 1 equiv of AgX (X = BAr_F, BF₄, PF₆) resulted in a one-electron oxidation to yield the paramagnetic Rh(II) complexes 9−11, respectively. Complex 11 was characterized by X-ray diffraction, revealing a mononuclear square-planar Rh(II) complex.