A study of polymeric platinum(II) compounds and Nanoscale materials

Abstract

The photophysical and structural properties of the tetra-u- pyrophosphitodiplatinate (2-) anion have been well studied in the past. One such analogue of this compound is a phosphorescent red compound of unknown structure. A new synthesis route has been was found for both the tetra-u- pyrophosphitodiplatinate (2-) and the red anionic compounds. By synthesizing the pyrophosphorus ligand outright and reacting that with tetrachloroplatinate (2-) either the tetra-u-pyrophosphitodiplatinate (2-) or the red anionic compounds can be synthesized depending on the amount of the phosphorus acid that is present. It was found from light scattering measurements and with the usage of 31P NMR spectroscopy that the red platinum(II) compound is structurally different than that of tetra-u-pyrophosphitodiplatinate (2-). A revised synthetic route was made for the synthesis of pyrophosphorus acid which was found to be an insoluble, highly reactive ligand. Reactions of pyrophosphorus acid with normal alcohols led to the formation of phosphorus acid and the corresponding monoalkylated phosphorus acid.

With the use of the monoalkylated phosphorus acids, an extensive series of dialkylated pyrophosphorus acids could be prepared thus creating a whole new series of novel platinum(II) compounds. The structural properties of two types of oligomeric platinum compounds were investigated. When saturated solutions of the bisoxalatoplatinate(2-) and tetracyanoplatinate(2-) salts were exposed to a direct current at a potential of 1.5V, partial oxidation of the platinum center occurred and polymerization of the platinum complexes was observed. It was found, using optical microscopy, atomic force microscopy, scanning electron microscopy and transmission electron microscopy that bundles of these polymers were formed having sizes on the macroscopic or nanoscopic scales. The polymeric one-dimensional, linear-chain compounds were found to be "Template guidable" on both the macro and nano scales in order to form polymers with virtually any diameter. The smallest of these partially oxidized polymers were measured as having diameters as little as three to four nanometers wide.