Synthesis, Structure, and Catalytic Application of a New (3-Methoxy-N-salicylidene) aniline-Derived Schiff Base Complex of Methyltrioxorhenium

A new (3-methoxy-N-salicylidene) aniline-derived Schiff base complex of methyltrioxorhe- nium (C(14)H(13)NO(2) center dot CH(3)ReO(3)) (I), displaying a cis-arrangement of the Schiff base ligand to the Re-bonded methyl group, has been synthesized and characterized by elemental analysis, IR, 1H NMR, and single-crystal X-ray diffraction. The X-ray diffraction analysis reveals that I crystallizes in the triclinic system, space group P (1) over bar, which displays a distorted trigonal-bipyramidal structure in the solid with the O-moiety binding to the Lewis acidic Re atom. The intermolecular hydrogen bands link the molecules of the complex into a two- dimensional layer structure. The presence of the pi-pi stacking interactions enhances the stability of the layers, which are further linked via pi-pi stacking interactions forming a three-dimensional supramolecular network. The unit cell parameters for I: a = 7.0032(14), b = 9.3762(19), c = 11.649(2) angstrom, alpha = 84.60(3)degrees, beta = 89.08(3)degrees, gamma = 84.45(3)degrees, V = 757.9(3) angstrom(3), Z = 2, F(000) = 456, R(1) = 0.0591, omega R(2) = 0.1346. In order to study the catalytic activity of complex I, cis-cyclooctene epoxidation in dichloromethane is examined. The result shows that the electron-donating OCH(3) group on the Schiff base influences the catalytic behavior significantly.