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[This corrects the article DOI: 10.1098/rsos.211022.][This corrects the article DOI: 10.1098/rsos.211022.].
RESUMO
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 H2O2, it is critical to assess the underlying CO release mechanism(s). In this context, a quantitative mechanistic investigation of the H2O2 oxidation of the water-soluble model complex fac-[Mn(CO)3(Br)(bpCO2)]2-, (A, bpCO2 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 H2O2 oxidation of A via pH-dependent kinetics that are first-order both in [A] and in [H2O2]. 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.
RESUMO
Geometry, chemical bonding, and aromatic feature of a series of small silver clusters doped by an Sc atom (ScAgn with n = 1-7) were investigated by means of density functional theory calculations. A planar shape is found for ScAgn including n from 4 to 7. The growth mechanism is established for the formation of the hexagonal and heptagonal metallic cycles following increase of the number of Ag atoms. Particularly, both clusters ScAg6- and ScAg7 present a planar cyclic form in which the Sc atom is situated at the central position of the Ag6 and Ag7 cycles. The σ aromaticity is unambiguously demonstrated by the existence of strongly diatropic current flows within the ring in both ScAg6- and ScAg7. The isovalent ScCu7 cluster has a similar ring current characteristic. In the Sc-doped ScAgn clusters, a delocalized bonding pattern is found as a connector between the dopant Sc and the Agn host, as indicated by an ELI_D analysis.