Photo-triggered NO release of nitrosyl complexes bearing first-row transition metals and therapeutic applications.

In biological systems, nitric oxide (NO) is a crucial signaling molecule that regulates a wide range of physiological and pathological processes. Given the significance of NO, there has been considerable interest in delivering NO exogenously, particularly through light as a non-invasive therapeutic approach. However, due to the high reactivity and instability of NO under physiological conditions, directly delivering NO to targeted sites remains challenging.

A functional model for quercetin 2,4-dioxygenase: Geometric and electronic structures and reactivity of a nickel(II) flavonolate complex.

Quercetin 2,4-dioyxgenase (QueD) has been known to catalyze the oxygenative degradation of flavonoids and quercetin. Recent crystallographic study revealed a nickel ion occupies the active site as a co-factor to support O activation and catalysis. Herein, we report a nickel(II) flavonolate complex bearing a tridentate macrocyclic ligand, [Ni(Me-TACN)(Fl)(NO)](HO) (1, Me-TACN = 1,4,7-trimethyl-1,4,7-triazacyclononane, Fl = 3-hydroxyflavone) as a functional model for QueD.