Synthesis of polyradicals by the oxidative coupling copolymerization of 2‐(3,5‐diethynylphenyl)‐4,4,5,5‐tetramethyl‐3‐oxo‐2‐imidazolin‐1‐yloxyl and 1,3,5‐triethynylbenzene catalyzed by CuCl/O2, and their magnetic properties

The present paper describes the synthesis of polyradicals by the oxidative coupling polymerization of 2‐(3,5‐diethynylphenyl)‐4,4,5,5‐tetramethyl‐3‐oxo‐2‐imidazolin‐1‐yloxyl (1) and 1,3,5‐triethynylbenzene (2) catalyzed by CuCl/O2, and their magnetic properties. The polyradicals obtained are dark blue and insoluble in all solvents examined. The ESR measurements of the polyradicals give a broad single‐line spectrum indicating that spin‐exchange narrowing takes place. The spin concentrations determined by the ESR spectroscopic method are 1,17 · 1021 to 1,28 · 1021 spins/g. The vibrating sample magnetometer (VSM) measurements of the polyradicals afford a linear magnetic moment vs. magnetic field dependence with a positive slope, suggesting that the copolymer has predominant paramagnetic properties within the limits of experimental error.