Photoaquation of cis-Bis(azine)tetraammineruthenium(II) complexes, cis-Ru(NH sub 3 ) sub 4 (L)(L prime ) sup n+1

Journal Article · Wed May 01 04:00:00 EDT 1991 · Inorganic Chemistry; (United States)

DOI:https://doi.org/10.1021/ic00009a043· OSTI ID:6105929

Pavanin, L A; da Rocha, Z N; Giesbrecht, E; Tfouni, E ^[1]

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1. Univ. de Sao Paulo (Brazil)

Near uV-visible range photolysis of cis-Ru{sup II}(NH{sub 3}){sub 4}(L){sub 2} (: = pyridine (py), 4-picoline (4-pic), isonicotinamide (isn), or 4-acetylpyridine (4-acpy)) and cis-Ru{sup II}(NH{sub 3}){sub 4}(isn)(L) (L = py, 4-pic, pyrazine, or 4-acpy) lead to isn, L, and ammonia aquation. The complexes were irradiated at 313, 365, 405, 436, 480, and 519 nm, in acidic (pH 3.5-4.0) aqueous solution and with {approximately} 10{sup {minus}3} M Ru complex concentration. The cis complexes have ligand field (LF) and metal-to-ligand charge-transfer (MLCT) states as the lowest energy excited states. The relative yields of the photoreactions of the cis complexes show patterns consistent with the excited-state tuning model proposed to explain photochemical properties of the pentaammine analogues, Ru{sup II}(NH{sub 3}){sub 5}(L), which undergo photosubstitution when LF is the lowest energy excited state, as is also the case for the trans complexes. For each cis complex, a fixed ratio of released ligands is observed at all irradiation wavelengths studied, this being a strong evidence that the observed photoreactions occur from one single LF excited state, or an ensemble of equilibrated LF excited states of the same electronic configuration. Ligands are more easily labilized along the axis with the weaker {pi}-acceptor ability. For a particular axis, the ligand with lower {pi}-acceptor ability is more easily labilized. 18 refs., 3 figs., 5 tabs.

• OSTI ID: 6105929
• Journal Information: Inorganic Chemistry; (United States), Journal Name: Inorganic Chemistry; (United States) Vol. 30:9; ISSN 0020-1669; ISSN INOCA
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140505 -- Solar Energy Conversion-- Photochemical
Photobiological
& Thermochemical Conversion-- (1980-)
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
400500 -- Photochemistry
AMIDES
AMMINES
AZINES
CHEMICAL REACTIONS
CHEMISTRY
COMPLEXES
DATA
DECOMPOSITION
ENERGY LEVELS
EXCITED STATES
EXPERIMENTAL DATA
HETEROCYCLIC COMPOUNDS
INFORMATION
NICOTINAMIDE
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOCHEMISTRY
PHOTOLYSIS
PICOLINES
PYRAZINES
PYRIDINES
RUTHENIUM COMPLEXES
TRANSITION ELEMENT COMPLEXES
VITAMIN B GROUP
VITAMINS