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Ruthenium Tetraammines as a Model of Nitric Oxide Donor Compounds
Author(s) -
Toledo José Carlos,
Silva Hildo A. S.,
Scarpellini Marciela,
Mori Vânia,
Camargo Ademir J.,
Bertotti Mauro,
Franco Douglas W.
Publication year - 2004
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200300683
Subject(s) - chemistry , chronoamperometry , ruthenium , electrochemistry , reaction rate constant , redox , dissociation (chemistry) , ligand (biochemistry) , medicinal chemistry , inorganic chemistry , stereochemistry , cyclic voltammetry , kinetics , electrode , organic chemistry , catalysis , receptor , biochemistry , physics , quantum mechanics
The nitric oxide liberation from trans ‐[Ru(NH 3 ) 4 (L)(NO)] 3+ (where L = py, 4‐pic, isn, nic, L ‐His, 4‐Clpy, imN) after one‐electron‐chemical or electrochemical reduction was investigated through spectroscopic and electrochemical techniques, reaction‐product analysis and quantum‐mechanic calculations. These complexes can be formally viewed as a Ru II (NO + ) species and the reduction site is located on the NO ligand. The E ° for the trans ‐[Ru II (NH 3 ) 4 (L)(NO + )] 3+ / trans ‐[Ru II (NH 3 ) 4 (L)(NO)] 2+ redox process ranges from 0.072 V vs. NHE (nic) to −0.118 V vs. NHE (imN). The specific rate constants for NO dissociation from trans ‐[Ru II (NH 3 ) 4 (L)(NO)] 2+ , evaluated through double‐step chronoamperometry, range from 0.025 s −1 (nic) to 0.160 s −1 (ImN) at 25 °C. The [Ru II NO + /Ru II NO 0 ] redox potential and the specific rate constant ( k ‐NO ),key steps for designing nitrosyl complexes as NO‐donor drug prototypes, proved to be controlled by a judicious choice of the ligand (L) trans to NO. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)