Reactivity and coordination chemistry of aromatic carboxamide RC(O)NH[sub 2] and carboxylate ligands: Properties of pentaammineruthenium(II) and -(III) complexes

Journal Article · Wed Apr 13 00:00:00 EDT 1994 · Inorganic Chemistry; (United States)

DOI:https://doi.org/10.1021/ic00086a018· OSTI ID:7102240

Chou, M H; Creutz, C; Sutin, N; Szalda, D J ^[1]

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1. Brookhaven National Lab., Upton, NY (United States)

The pH dependences of the spectral and electrochemical properties of mononuclear carboxamido (NH[sub 3])[sub 5]RuNHC(O)R (R = Ph, 4-py-NH-Me[sup +], 4-py-N-H[sup +]) and carboxylato (NH[sub 3])[sub 5]RuOC(O)R (R = 4-py-N-Me[sup +]) complexes of Ru(II) and Ru(III) in aqueous solution have been examined. In contrast to the carboxylate complex (E[sub 1/2] = -0.053 V vs NHE), the deprotonated (-NHC(O)R[sup [minus]]) Ru[sup III/II] couples have rather negative reduction potentials, -0.25 (R = Ph), -0.23 (R = 4-py), and -0.13 (R = N-Me-4-py) V vs NHE, which are pH independent above the pK[sub a] of the Ru(II) complex (pH 4-8 depending upon R). In contrast, the carboxamido-Ru(III) complexes are weak bases, being protonated only in strongly acidic solutions (e.g. 5 M HClO[sub 4]). From the structural work (d(Ru(III)-amido N) for R = N-Me-4-py is 1.998(9) [angstrom]) and the behavior of the ligand-to-metal charge-transfer bands in carboxamido-Ru(III) complexes, considerable oxygen [pi]p-ruthenium(III) [pi]d bonding is inferred. Kinetic and equilibrium studies for the protonation of the Ru(II) amide and carboxylate complexes and for alkaline hydrolysis of the amide ligands is reported.

• OSTI ID: 7102240
• Journal Information: Inorganic Chemistry; (United States), Journal Name: Inorganic Chemistry; (United States) Vol. 33:8; ISSN 0020-1669; ISSN INOCAJ
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ABSORPTION SPECTROSCOPY
AMIDES
AROMATICS
CHEMICAL REACTIONS
CHEMISTRY
COMPLEXES
DECOMPOSITION
ELECTROCHEMISTRY
HYDROLYSIS
LYSIS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PH VALUE
RUTHENIUM COMPLEXES
SOLVOLYSIS
SPECTROSCOPY
TRANSITION ELEMENT COMPLEXES