Pt(II)-Based Metallo-Supramolecular Polymers

Abstract

This chapter introduces synthesis and electronic properties of Pt(II)-based metallo-supramolecular polymer. Section 7.1 shows synthesis of a Pt(II)-based metallo-supramolecular polymer with a head-to-tail polymer structure (polyPtL17) using a combination of an asymmetrical ligand (L17) and stepwise complexation. L17 containing a terpyridine moiety and a pyridine moiety is prepared by a Suzuki-type cross coupling reaction. The head-to-tail structure of polyPtL17 is supported by the peak assignment of the ¹H NMR and H-H COSY spectra. The low-intensity signals of the terminal pyridyl protons show that the degree of polymerization is 40. Section 7.2 describes rectification properties of the polymer film. To investigate the electronic properties of polyPtL17, the polymer is grafted onto functionalized Au electrodes to produce two films with their dipole moments aligned in different directions. Then, to complete the fabrication of the device, a second 10-nm-thick Au strip is deposited orthogonally to the first Au electrode to form a sandwich of the polymer between the two Au electrodes in each film. The electronic properties of the two films are determined by current–voltage (I–V) measurements. The I−V characteristics show an asymmetric charge-transport behavior resulting from intrinsic polarization in the oriented sandwiched polymer chain as a result of its inherent dipole.