摘要:
Thermolysis of Ni(OTf)(2) in 2-phenyl-pyridine or 2-tolyl-pyridine afforded the cationic chelate derivatives, [bis(2-aryl-pyridine)Ni{(2aryl-kappa C-2)pyridine-kappa N]OTf (aryl = phenyl, 1a; tolyl, 1b). Addition of KBr to 1a and LiBr to 1b provided the bromides, (2-aryl-pyridine)BrNi{ (2-aryl-KC2)pyridine-KN} (aryl = phenyl, 2a; tolyl, 2b). When subjected to KO'Bu in Et2O, the bromides generated the entitled bis-cyclometalated compounds, Ni((2-aryl-KC2)pyridine-kappa N-2 (aryl = phenyl, 3a; tolyl, 3b). These compounds insert diphenylacetylene into one cyclometalate arm to produce [(2-aryl-kappa C-2)pyridine-KN]Ni[2-(2-(1,2-diphenylethenyl-kappa C-2)aryl)pyridine-KN] (aryl = phenyl, 4a; p-tolyl, 4b). X-ray crystallographic studies were conducted on la, 2a, 3a and 4a, and a brief DFT study of 3a confirmed its low spin configuration and rippled geometry. (C) 2007 Elsevier B.V. All rights reserved.