Modulation of single-molecule magnet behaviour via photochemical [2+2] cycloaddition.

The first example of phototunable SMMs has been reported. Upon UV irradiation, variations of the coordination sphere around Dy(iii) ions actually affect the magnetic behaviour of the compound via [2+2] cycloaddition reaction, leading to a magnetic transformation from the SMM behaviour to a field-induced slow relaxation. [ABSTRACT FROM AUTHOR]