Heterospin complex showing spin transition at room temperature

Abstract

© 2015 Elsevier Ltd. All rights reserved. New nitronyl nitroxides L^Me and L^Me-CP containing a 4-methylpyridin-3-yl substituent were synthesized. It was found that the interaction of Cu(hfac)<inf>2</inf> with L^Me and L^Me-CP gave binuclear [Cu(hfac)<inf>2</inf>L^Me]<inf>2</inf> and [Cu(hfac)<inf>2</inf>L^Me-CP]<inf>2</inf>·Solv (Solv = n-C<inf>6</inf>H<inf>14</inf>, n-C<inf>10</inf>H<inf>22</inf>, n-C<inf>16</inf>H<inf>34</inf>) and chain polymer {[[Cu(hfac)<inf>2</inf>]<inf>2</inf>L^Me<inf>2</inf>][Cu(hfac)<inf>2</inf>]}<inf>∞</inf> heterospin complexes. An important structural peculiarity of L^Me and L^Me-CP is a large dihedral angle between the planes of the O•-N-CN → O paramagnetic fragment and the pyridine ring: 55.2 and 56.1°, respectively. The presence of a methyl group in the pyridine ring of the nitroxide molecule in {[[Cu(hfac)<inf>2</inf>]<inf>2</inf>L^Me<inf>2</inf>][Cu(hfac)<inf>2</inf>]}<inf>∞</inf> proved favorable for spin transition at nearly room temperature.