Heterospin complex showing spin transition at room temperature

New nitronyl nitroxides L-Me and LMe-CP containing a 4-methylpyridin-3-yl substituent were synthesized. It was found that the interaction of Cu(hfac)(2) with L-Me and LMe-CP gave binuclear [Cu(hfac)(2)L-Me](2) and [Cu(hfac)(2)LMe-CP](2)center dot Solv(Solv = n- C6H14, n-C10H22, n-C16H34) and chain polymer {[[Cu(hfac)(2)](2)L-2(Me)] [Cu(hfac)(2)]}(infinity) heterospin complexes. An important structural peculiarity of L-Me and LMe-CP is a large dihedral angle between the planes of the O-center dot-N-C=N -> O paramagnetic fragment and the pyridine ring: 55.2 and 56.1 degrees, respectively. The presence of a methyl group in the pyridine ring of the nitroxide molecule in {[[Cu(hfac)(2)](2)L-2(Me)][Cu(hfac)(2)]}(infinity) proved favorable for spin transition at nearly room temperature. (C) 2015 Elsevier Ltd. All rights reserved.