Bis(arene) chromium-containing polyacrylonitrile and its thermolysis products: Synthesis, characterization and magnetic properties

Polyacrylonitrile bonded to bis(arene)chromium complexes was prepared by th e polycyanoethylation reaction between acrylonitrile and various bis(arene) chromium complexes. The star-shaped molecules consisted of a central bis(ar ene)chromium species with up to four polyacrylonitrile arms (each composed of up to 63 acrylonitrile units) covalently bonded to the arene ligands. Th e products of thermolysis of the polymers at 160 degrees C and 350 degrees C were characterized by elemental analysis as well as infrared, nuclear mag netic resonance, electron paramagnetic resonance, Mossbauer and X-ray photo electron spectroscopies. Thermolysis at 160 degrees C resulted in essential ly complete decomposition of the bis(arene)chromium complexes, the polyacry lonitrile chains remaining unaffected. At thermolysis temperatures above 30 0 degrees C, cyanogen and ammonia weue evolved, spectroscopic studies of th e resulting material indicating formation of conjugated polynaphthyridine-t ype products containing ketoimine fragments. The product of thermolysis at 160 degrees C showed room temperature ferromagnetism and that obtained at 3 50 degrees C tons an antiferromagnet with a Neel temperature of ca. 150 K. Copyright (C) 1999 John Wiley & Sons, Ltd.