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]

---

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), Vol. 33:8; ISSN 0020-1669
• Country of Publication: United States
• Language: English

Related Subjects

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