Disproportionation of Bis(phosphaethenyl)pyridine Iron(I) Bromide Induced by tBuNC

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• 作者：Ya-Fan Lin ; Nobuko Ichihara ; Yumiko Nakajima ; Fumiyuki Ozawa
• 刊名：Organometallics
• 出版年：2014
• 出版时间：November 24, 2014
• 年：2014
• 卷：33
• 期：22
• 页码：6700-6703
• 全文大小：284K
• ISSN：1520-6041

文摘

Redox behavior of Fe(I) complexes bearing a PNP-pincer-type phosphaalkene ligand, 2,6-bis[1-phenyl-2-(2,4,6-tri-tert-butylphenyl)-2-phosphaethenyl]pyridine (BPEP-Ph), is reported. The four-coordinate Fe(I) complex [FeBr(BPEP-Ph)] (1) readily reacts with 1 equiv of tBuNC in toluene at 鈭?5 掳C to give [FeBr(tBuNC)(BPEP-Ph)] (2) with a 17e configuration. Complex 2 is fairly stable in neat benzene at room temperature, but smoothly undergoes disproportionation in the presence of added tBuNC to afford the Fe(0) complex [Fe(tBuNC)₂(BPEP-Ph)] (3) and the Fe(II) complex [FeBr₂(tBuNC)₄] (4) along with free BPEP-Ph. The single-crystal X-ray diffraction studies of 3 and 4 reveal distorted trigonal bipyramidal and square pyramidal arrangements around Fe, respectively. The yield of 3 increases up to 50%/2 when 2 equiv of tBuNC is added to the system. A disproportionation process involving a 19e intermediate is proposed.