Open AccessRedox-mediated carbon monoxide release from a manganese carbonyl—implications for physiological CO delivery by CO releasing moieties
Author(s) -
Jacob Barrett,
Zhi Li,
John V. Garcia,
Emily Wein,
Dongyun Zheng,
C.E.L. Hunt,
Loc Ngo,
Lior Sepunaru,
Alexei V. Iretskii,
Peter C. Ford
Publication year - 2021
Publication title -
royal society open science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.84
H-Index - 51
ISSN - 2054-5703
DOI - 10.1098/rsos.211022
Subject(s) - carbon monoxide , chemistry , redox , hydrogen peroxide , context (archaeology) , reactivity (psychology) , kinetics , reaction mechanism , manganese , combinatorial chemistry , photochemistry , catalysis , inorganic chemistry , organic chemistry , medicine , paleontology , physics , alternative medicine , pathology , quantum mechanics , biology
The dynamics of hydrogen peroxide reactions with metal carbonyls have received little attention. Given reports that therapeutic levels of carbon monoxide are released in hypoxic tumour cells upon manganese carbonyls reactions with endogenous H 2 O 2 , it is critical to assess the underlying CO release mechanism(s). In this context, a quantitative mechanistic investigation of the H 2 O 2 oxidation of the water-soluble model complex fac -[Mn(CO) 3 (Br)(bpCO 2 )] 2– , ( A , bpCO 2 2– = 2,2′-bipyridine-4,4′-dicarboxylate dianion) was undertaken under physiologically relevant conditions. Characterizing such pathways is essential to evaluating the viability of redox-mediated CO release as an anti-cancer strategy. The present experimental studies demonstrate that approximately 2.5 equivalents of CO are released upon H 2 O 2 oxidation of A via pH-dependent kinetics that are first-order both in [ A ] and in [H 2 O 2 ]. Density functional calculations were used to evaluate the key intermediates in the proposed reaction mechanisms. These pathways are discussed in terms of their relevance to physiological CO delivery by carbon monoxide releasing moieties.