TY - JOUR
T1 - Overview and New Insights into the Thiol Reactivity of Coordinated NO in {MNO}6/7/8 (M = Fe, Co) Complexes
AU - Rhine, Melody A.
AU - Sanders, Brian C.
AU - Patra, Ashis K.
AU - Harrop, Todd C.
N1 - Publisher Copyright:
© 2015 American Chemical Society.
PY - 2015/6/18
Y1 - 2015/6/18
N2 - The reactivity of free NO (NO+, NO•, and NO-) with thiols (RSH) is relatively well understood, and the oxidation state of the NO moiety generally determines the outcome of the reaction. However, NO/RSH interactions are often mediated at metal centers, and the fate of these species when bound to a first-row transition metal (e.g., Fe, Co) deserves further investigation. Some metal-bound NO moieties (particularly NO+, yielding S-nitrosothiols) have been more thoroughly studied, yet the fate of these species remains highly condition-dependent and, for M-NO-, an unexplored field. Herein, we present an overview of thiol reactions with metal nitrosyls that result in N-O bond activation, ligand substitution on {MNO} fragments, and/or redox chemistry. We also present our results pertaining to the thiol reactivity of nonheme {FeNO}7/8 complexes [Fe(LN4pr)(NO)]-/0 (1 and 2) and the noncorrin {CoNO}8 complex [Co(LN4pr)(NO)] (3), an isoelectronic analogue of the {FeNO}8 complex 1. Among other products, the reaction of 1 with p-ClPhSH affords [Fe2(μ-SPh-p-Cl)2(NO)4]- (anion of 6), a reduced Roussin's red ester (rRRE), which was characterized by Fourier transform infrared (FTIR), UV-vis, electron paramagnetic resonance (EPR), and X-ray diffraction. Similarly, the reaction of 1 with glutathione in buffer affords the corresponding rRRE, which has also been spectroscopically characterized by EPR and UV-vis. The oxidation states of the metals and nitrosyls both contribute to the complex nature of these interactions, and as such, we discuss the varying product distribution accordingly. These studies shed insight into the products that may form through MNO/RSH interactions that lead to NOx activation and {MNO} redox.
AB - The reactivity of free NO (NO+, NO•, and NO-) with thiols (RSH) is relatively well understood, and the oxidation state of the NO moiety generally determines the outcome of the reaction. However, NO/RSH interactions are often mediated at metal centers, and the fate of these species when bound to a first-row transition metal (e.g., Fe, Co) deserves further investigation. Some metal-bound NO moieties (particularly NO+, yielding S-nitrosothiols) have been more thoroughly studied, yet the fate of these species remains highly condition-dependent and, for M-NO-, an unexplored field. Herein, we present an overview of thiol reactions with metal nitrosyls that result in N-O bond activation, ligand substitution on {MNO} fragments, and/or redox chemistry. We also present our results pertaining to the thiol reactivity of nonheme {FeNO}7/8 complexes [Fe(LN4pr)(NO)]-/0 (1 and 2) and the noncorrin {CoNO}8 complex [Co(LN4pr)(NO)] (3), an isoelectronic analogue of the {FeNO}8 complex 1. Among other products, the reaction of 1 with p-ClPhSH affords [Fe2(μ-SPh-p-Cl)2(NO)4]- (anion of 6), a reduced Roussin's red ester (rRRE), which was characterized by Fourier transform infrared (FTIR), UV-vis, electron paramagnetic resonance (EPR), and X-ray diffraction. Similarly, the reaction of 1 with glutathione in buffer affords the corresponding rRRE, which has also been spectroscopically characterized by EPR and UV-vis. The oxidation states of the metals and nitrosyls both contribute to the complex nature of these interactions, and as such, we discuss the varying product distribution accordingly. These studies shed insight into the products that may form through MNO/RSH interactions that lead to NOx activation and {MNO} redox.
UR - http://www.scopus.com/inward/record.url?scp=84942925981&partnerID=8YFLogxK
U2 - 10.1021/acs.inorgchem.5b00883
DO - 10.1021/acs.inorgchem.5b00883
M3 - Article
C2 - 26086436
AN - SCOPUS:84942925981
SN - 0020-1669
VL - 54
SP - 9351
EP - 9366
JO - Inorganic Chemistry
JF - Inorganic Chemistry
IS - 19
ER -