Synthesis, characterisation and physicochemical properties of polyphenols prepared by cobalt(II) catalysed oxidative polymerisation

The catalytic reaction of Co-2(DAM)(7)Cl-4 with phenolic compounds such as phenol, p-cresol, o-cresol, m-cresol etc, in the presence of hydrogen perox ide gave C-O bonded oligomers (1-4). The oligomers were characterised by NM R, IR, elemental analysis. The M-n values of 1-4 were 3417, 3394, 3438 and 3550, respectively. The oligomers contain OH end groups. The oligomer 1 has resistance profile such that it increases to 50 degreesC and then falls ex ponentially in the region of 50 to 170 degreesC. The resistance of 2 and 4 are similar to semiconductor in the range of 30-180 degreesC. The oligomer 3 has a resistance profile such that it decreases from 30 to 100 degreesC a nd then increases from 100 to 140 degreesC and once again falls in the regi on of 140-200 degreesC. The oligomer 4 has an esr signal at 3220 G and show s the presence of a free radical. The intensity of this signal increases te n times upon heating to 90 degreesC. (C) 2000 Elsevier Science B.V. All rig hts reserved.