Ligand displacement reactions. Part V. The mechanisms of displacement of bidentate olefins from olefin(tetramethyl-1,4-benzoquinone)-nickel(0) complexes by trimethyl phosphite
作者:A. Pidcock、G. G. Roberts
DOI:10.1039/j19700002922
日期:——
give bis(tributylphosphine)(tetramethyl-1,4-benzoquinone)nickel. With trimethyl phosphite the olefin complexes give tetrakis(trimethyl phosphite)nickel and, although intermediates cannot be detected, it is shown that displacement of the olefin precedes that of the quinone. The rate laws found for the reactions of trimethyl phosphite (P) with various olefin complexes (C) are for cyclo-octa-1,5-diene,
三丁基膦与烯烃(四甲基-1,4-苯醌)镍(烯烃=环辛酸酯或环辛-1,5-二烯)配合物反应生成双(三丁基膦)(四甲基-1,4-苯醌)镍。对于亚磷酸三甲酯,烯烃络合物产生四(亚磷酸三甲酯)镍,尽管无法检测到中间体,但显示出烯烃的置换先于醌的置换。对于亚磷酸三甲酯(P)与各种烯烃配合物(C)的反应,发现的速率定律是环辛基-1,5-二烯,速率= k 1 [C] [P] + k 2 [C] [ P] 2 } /(1 + k 3 [P]);对于环辛酸酯和降冰片烯2,5-二烯,比率= k 1 [C] [P] + k2 [C] [P] 2 ; 对于内切-dicyclopentadiene率= ķ 1 [C] [P]。亚磷酸三甲酯与双(四甲基-1,4-苯醌)镍和三丁基膦与环辛-1,5-二烯配合物的反应速率为k 1[C] [P]。通过涉及(C)和(P)的初始双分子反应以形成其中烯烃为单齿的中间体(A)的机