Heterospin complex showing spin transition at room temperature

New nitronyl nitroxides LMe and LMe-CP containing a 4-methylpyridin-3-yl substituent were synthesized. It was found that the interaction of Сu(hfac)2 with LMe and LMe-CP gave binuclear [Cu(hfac)2LMe]2 and [Cu(hfac)2LMe-CP]2·Solv (Solv = n-C6H14, n-C10H22, n-C16H34) and chain polymer {[[Cu(hfac)2]2LMe2][Cu(hfac)2]}∞ heterospin complexes. An important structural peculiarity of LMe and LMe-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)2]2LMe2][Cu(hfac)2]}∞ proved favorable for spin transition at nearly room temperature.

Graphical abstractNovel binuclear [Cu(hfac)2LMe]2, [Cu(hfac)2LMe-CP]2 and chain polymer {[[Cu(hfac)2]2LMe2][Cu(hfac)2]}∞ heterospin complexes revealed spin-crossover-like phenomenon.Figure optionsDownload full-size imageDownload as PowerPoint slide