Molecular design of the polymer forming the complex with metal. Part III. Structural studies of pyridine-containing poly(dimethyl siloxane) complexed with zinc

Abstract The molecular structure of an N -pyrid-2-ylmethyl amide (MPY) group–Zn complex with the effective function as the hard-segment of a thermoplastic elastomer was investigated by X-ray crystal analysis and EXAFS spectroscopy. The MPY group of poly(dimethyl siloxane) modified by the MPY (MPYSI) forms stoichiometrically the 1:1 chelate complex with Zn salts. This complex has a rigid and slightly bent planar structure, which consists of chelate and pyridine rings side by side. In addition, the X-ray analysis and MO calculation suggest that the MPY–Zn complex has a remarkably large dipole moment (2-MPYVA–ZnBr 2 : 16.6 D, uncomplexed 2-MPYVA: 4.8 D). These results suggest that the MPY–Zn complex shows a stoichiometric complexation, a large dipole moment, and a rigid and planar structure, so that they effectively aggregate even if the MPY group is connected to the polymer chain with a lesser substitution degree.