Highly coupled mixed-valence dinuclear ruthenium and osmium complexes with a bis-cyclometalating terpyridine analogue as bridging ligand

Journal Article · Wed Oct 13 04:00:00 EDT 1993 · Inorganic Chemistry; (United States)

DOI:https://doi.org/10.1021/ic00073a012· OSTI ID:7207388

Beley, M; Collin, J P; Sauvage, J P ^[1]

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1. Universite Louis Pasteur, Strasbourg (France)

Long-range electron transfer and photoinduced charge separation are essential processes related to the development of molecular electronic and solar energy conversion devices. The dinuclear complexes (tterpy)M(typbp)M(tterpy)[sup 2+] (M = Ru(II) or Os(II), tterpy = 4[prime], -p-tolyl-2,2[prime]:6[prime], 2[close quotes]-terpyridine, tpbpH[sub 2] = 3,3[prime],5,5[prime]-tetrapyridylbiphenyl) have been prepared by oxidative coupling of the corresponding monomers M(tterpy)(dpb)[sup +] (dpbH = 1,3-di-o-pyridylbenzene). Spectrochemical and electrochemical properties of the monomers and dimers in different oxidation states are described. Chemical or electrochemical oxidation of the M(II)-M(II) species leads to the mixed-valence M(II)-M(III) dimer. The comproportionation constants K[sub c] determined by cyclic voltammetry (600 and 100 for Ru and Os, respectively) reflect the high stability of the M(II)-M(III) states. In addition, the near-infrared spectrum of each mixed-valence ion exhibits a very intense intervalence transfer (IT) transition. Although the two metal centers are separated by a large distance (11 [angstrom]), the matrix elements V[sub ab] are relatively large (0.15 and 0.12 eV for Ru and Os, respectively). This demonstrates the surprisingly high coupling ability of the bis-cyclometalating bridging ligand tpbp[sup 2[minus]].

• OSTI ID: 7207388
• Journal Information: Inorganic Chemistry; (United States), Journal Name: Inorganic Chemistry; (United States) Vol. 32:21; ISSN 0020-1669; ISSN INOCAJ
• Country of Publication: United States
• Language: English

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