Electrochemical reduction of (2, 2'-bipyridine)-and bis((2-pyridyl)pyrazine)ruthenium(II) complexes used as building blocks for supramolecular species. Redox series made of 8, 10, and 12 redox steps

Journal Article · Wed Jul 07 00:00:00 EDT 1993 · Inorganic Chemistry; (United States)

DOI:https://doi.org/10.1021/ic00066a008· OSTI ID:5771007

Roffia, S; Marcaccio, M; Paradisi, C; Paolucci, F; Balzani, V ^[1]; Denti, G; Serroni, S ^[2]; Campagna, S ^[3]

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1. Universita di Bologna (Italy)
2. Universita di Pisa (Italy)
3. Universita di Messina (Italy)

The electrochemical reduction of the [Ru(2, 3-dpp)n(bpy)[sub 3[minus]n]][sup 2+] complexes (n = 1[minus]3), which are extensively used as building blocks for the synthesis of polynuclear compounds, has been investigated at [minus]54[degrees]C in DMF solution up to a limit of [minus]3.1 V vs SCE (dpp is the potential bridging ligand bis(2-pyridyl)pyrazine and bpy is 2, 2'-bipyridine). For comparison purposes, the electrochemical behavior of the free 2, 3-dpp ligand has also been investigated. The results obtained have been discussed and compared with those previously reported for bpy and Ru(bpy)[sub 3][sup 2+]. Convolutive analysis and simulation of the cyclic voltammetric curves have been performed to obtain the redox potentials in the case of overlapping waves. [Ru(2, 3-dpp)[sub 3]][sup 2+], [Ru(2, 3-dpp)[sub 2](bpy)][sup 2+], and [Ru(2, 3-dpp)(bpy)[sub 2]][sup 2+] display 12, 10, and 8 reduction steps, respectively, in the potential window examined. The corresponding redox series are thus noticeably more extended than those exhibited by [Ru(bpy)[sub 3]][sup 2+] and related complexes not containing bridging-type ligands. The analysis of the genetic diagram which related the redox potentials observed for 2, 3-dpp, [Ru(2, 3-dpp)[sub 3]][sup 2+], [Ru(2, 3-dpp)[sub 2](bpy)][sup 2+], [Ru(2, 3-dpp)(bpy)[sub 2]][sup 2+], [Ru(bpy)[sub 3]][sup 2+], and bpy shows that each redox step in the metal complexes is essentially localized on a specific ligand. A satisfactory assignment of the redox sites has been proposed, and their mutual interactions have been discussed. The results obtained show that in order to arrive at a satisfactory assignment of the redox series for a complex containing redox-active ligands a comparison with the behavior of complexes of the same family is as much instructive as a comparison with the behavior of the free ligands.

• OSTI ID: 5771007
• Journal Information: Inorganic Chemistry; (United States), Journal Name: Inorganic Chemistry; (United States) Vol. 32:14; ISSN 0020-1669; ISSN INOCAJ
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400400* -- Electrochemistry
ANIONS
AZINES
BIPYRIDINES
CHARGED PARTICLES
CHEMICAL REACTIONS
CHEMISTRY
COMPLEXES
ELECTROCHEMISTRY
HETEROCYCLIC COMPOUNDS
IONS
LIGANDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIDINES
REDOX REACTIONS
REDUCTION
RUTHENIUM COMPLEXES
TRANSITION ELEMENT COMPLEXES
VOLTAMETRY