Synthesis, Structure, Reactivity, and Catalytic Activity of Cyclometalated (Phosphine)‐ and (Phosphinite)ruthenium Complexes. Issue 25 (5th July 2017) - Sun, Ruichen
Abstract : Reactions of naphthyl‐ and o ‐methylphenyl‐substituted phosphines with [RuCl2 ( p ‐cymene)]2 resulted in the corresponding phosphine‐substituted ruthenium dichlorides (1a, b and3 ). When the reactions of aryl‐substituted phosphines or phosphinites with [RuCl2 ( p ‐cymene)]2 are carried out in the presence of sodium acetate, aryl‐substituted phosphines or phosphinites are cyclometalated to give the corresponding five‐membered metallacycle complexes (2a, b and4 –6 ) through the intramolecular activation of a C(sp 2 )–H or C(sp 3 )–H bond. Competition reactions indicate that the aromatic C(sp 2 )–H bond is more likely to be activated than the C(sp 3 )–H bond under the same conditions, and that a five‐membered ring is formed in preference to a six‐membered ring. The chemical reactivity of2a, b, two representatives of cycloruthenated complexes, were explored, including conversion of1a, b to2a, b, a substitution reaction of the η 6 ‐arene ligand in2a, synthesis of a bis(phosphine) complex starting from2b, and reaction of2a with diphenylacetylene. Besides, their catalytic activity on the reduction of ketones by transfer hydrogenation was also tested. The molecular structures of nine compounds, 1b, 2a, and4 –10, were determined by single‐crystal X‐ray diffraction. Abstract : A series of five‐membered cycloruthenated complexes (2a, b and4, as well as two not shown) and phosphine‐substituted ruthenium dichlorides (1a, b and3 ) were synthesized under different conditions. The chemical reactivity of the cycloruthenated complexes was investigated, including their catalytic activity on the reduction of ketones by transfer hydrogenation.