“…10,11 Isomerization in these compounds is often accessible only by light excitation, thereby providing means for controlled reversible molecular switching that can be applied for data storage or sensor technologies. [12][13][14][15] Moreover, light activation of such complexes in solutions (especially in the case of NO compounds) could result in the release of free small molecules and can be used in photodynamic therapy for target drug delivery. 16,17 For the nitrosyl compounds, at least three types of NO coordination are known: M-NO (GS), M-ON (metastable state 1, MS1) and M-Z 2 -(NO) (MS2, side bond).…”