No-To-[N2o2](2-)-To-N2o Conversion Triggered By {Fe(No)(2)}(10)-{Fe(No)(2)}(9) Dinuclear Dinitrosyl Iron Complex

Flavodiiron nitric oxide reductases (FNORs) evolved in some pathogens are known to detoxify NO via two-electron reduction to N2O to mitigate nitrosative stress. In this study, we describe how the electronically localized {Fe(NO)(2)}(10)-{Fe(NO)(2)}(9) dinuclear dinitrosyl iron complex (dinuclear DNIC) [(NO)(2)Fe(mu-bdmap)Fe(NO)(2)(THF)] (2) (bdmap = 1,3-bis(dimethylamino)-2-propanolate) can induce a reductive coupling of NO to form hyponitrite-coordinated tetranuclear DNIC, which then converts to N2O. Upon the addition of 1 equiv of NO into the dinuclear {Fe(NO)(2)}(10)-{Fe(NO)(2)}(9) DNIC 2, the proposed sideon-bound [NO](-)-bridged [(NO)(2)Fe(mu-bdmap)(kappa(2)-NO)Fe(NO)(2)] intermediate may facilitate intermolecular (O)N-N(O) bond coupling to yield the paramagnetic tetranuclear quadridentate trans-hyponitrite-bound {[(NO)(2)Fe(mu-bdmap)Fe(NO)(2)](2)(kappa(4)-N2O2)} that transforms to [Fe(NO)(2)(mu-bdmap)](2), along with the release of N2O upon Hbdmap (1,3-bis(dimethylamino)-2-propanol) added.