Denny JA, Foley WS, Todd AD, Darensbourg MY. The ligand unwrapping/rewrapping pathway that exchanges metals in
S-acetylated, hexacoordinate N
2S
2O
2 complexes.
Chem Sci 2015;
6:7079-7088. [PMID:
29896341 PMCID:
PMC5954489 DOI:
10.1039/c5sc02269j]
[Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 09/05/2015] [Indexed: 12/13/2022] Open
Abstract
The effect of S-acetylation in MN2S2 complexes on metal exchange reactivity was examined in a series of MN2S2O2 complexes. While clean exchange processes do not occur for the MN2S2 derivatives where formation of S-bridged aggregates predominate, acetylation permits the metal exchange with hierarchy that follows the Irving-Williams series of stability for first row transition metals: Fe2+ < Co2+ < Ni2+ < Cu2+ > Zn2+. The rate determining step consistent with kinetic parameters depends on both M and M', supporting a mechanism of exchange that involves ligand unwrapping/rewrapping process as earlier defined by Margerum et al. for M(EDTA) systems. The enhanced metal exchange deriving from S-acetylation is of significance to probes and detection of cysteine-S metallo-proteins and metallo-enzyme active sites, and highlights a new role for S-acetylation.
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