Synthesis and structure of a thioazobenzene palladacycle: Oxygen insertion into the PdC bond by m-chloroperbenzoic acid
摘要:
The reaction of p-tolyl-o'-(2-chloroethylthio)azobenzene (LH-1)with Na2PdCl4 affords the complex PdL1Cl, the structure of which has been determined by X-Tay crystallography. The azobenzene ligand acts in the tridentate (C,N,S) fashion and the fourth coordination position is occupied by the chloride ion. In the lattice, the PdL1Cl molecules are present as loose dimers of parallel Pd(C,N,S)Cl units, the Pd ... Pd distance being 3.357(2) angstrom. Reaction of PdL1Cl with m-chloroperbenzoic acid leads to insertion of oxygen into the Pd-C bond to give the corresponding phenolato complex. The insertion reaction is of first order with respect to each of the reactants, and has a large negative entropy of activation. A plausible mechanism is proposed. The structure and properties of PdL1Cl are compared with those of related species.