A FOUR-MEMBERED C,O-CHELATE - TWO FAMILIES OF RUTHENIUM ORGANOMETALLICS INCORPORATING N-CENTER-DOT-CENTER-DOT-CENTER-DOT-O HYDROGEN BONDING

摘要

The reaction of mono-Schiff bases of 4-methyl-2,6-diformylphenol and primary amines (p-XC(6)H(4)NH(2), X = OMe, Cl, CO(2)Et and NO2) with Ru(PPh(3))(3)Cl-2 in boiling ethanol afforded violet diamagnetic complexes, [Ru(eta(2)-p-XC(6)H(4)L)(PPh(3))(2)(CO)Cl] (eta(2)-p-XC(6)H(4)L = [4-methyl-6-(N-p-Xphenyliminiomethyl) phenolato-C-2,O] incorporating the unprecedented orthoruthenated phenolate function, which is hydrogen-bonded with the uncoordinated imine nitrogen. These complexes were found to react with sodium benzoates (p-ZC(6)H(4)COO, Z = Me, Cl) to generate the new aryl complexes of ruthenium, [Ru(eta(1)-p-XC(6)H(4)L)(PPh(3))(2)(CO)(eta(2)-p-ZC(6)H(4)COO)]. The spectral (IR, UV-vis and H-1 NMR) features of these two types of complexes and the effect of the X substituent on electronic and H-1 NMR spectra are scrutinized. The effect of PPh(3) ring currents on the chemical shifts of the metallated ring protons is semiquantitatively estimated. In these complexes different types of novel intramolecular N...O interaction and the conformational orientation of p-XC(6)H(4)L ligands are noted. The redox behaviour of these complexes is reported. The E(1/2) values of Ru-III/Ru-II couple correlate linearly with the Hammett constants (sigma) of X substituent in the halo complexes. A spectro-electrochemical correlation in these complexes is also observed. Copyright (C) 1997 Elsevier Science Ltd. [References: 42]