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A series of reactions have been performed by mixing 2-diphenylphosphino-6-methyl-pyridine (dpPyMe) and [Cu(CH 3 CN) 4 ]BF 4 in different molar ratios. Starting from equimolar quantities of dpPyMe and Cu + , a dinuclear Cu(I) complex with two P,N binucleating bridging ligands has been obtained. This compound is stable in the solid state, however ligand exchange reactions leading to a mixture of species have been evidenced in solution. By increasing the amount of dpPyMe, the reaction of dpPyMe and [Cu(CH 3 CN) 4 ]BF 4 afforded the dinuclear Cu(I) complex [Cu 2 (μ-dpPyMe) 3 (CH 3 CN)](BF 4 ) 2 in which the three bridging dpPyMe ligands are in a head-to-head arrangement. This compound is remarkably stable in solution. It has been also shown that the axial CH 3 CN ligand of [Cu 2 (μ-dpPyMe) 3 (CH 3 CN)](BF 4 ) 2 can be suitably exchanged with other nitrile ligands [benzonitrile, 4-(dimethylamino)-benzonitrile, 4-nitrobenzonitrile and bromoacetonitrile] but also with triphenylphosphine oxide. The electrochemical and photophysical properties of the resulting complexes have been systematically investigated. The [Cu 2 (μ-dpPyMe) 3 (L)](BF 4 ) 2 derivatives are weak emitters in solution but remarkable emission quantum yields (6 to 46%) have been found in rigid matrices at room temperature. One complex was utilized as active material for preliminary tests in LEC devices. [ABSTRACT FROM AUTHOR]

Four Ru II complexes of general formula [Ru(PT) 3 ] 2+ , [Ru(NT) 3 ] 2+ , [Ru(PT)(bpy) 2 ] 2+ , and [Ru(NT)(bpy) 2 ] 2+ , where PT = 10,13-bis((triisopropylsilyl)ethynyl)dipyrido[3,2- a :2′,3′- c ]phenazine, NT = 10,15-bis((triisopropylsilyl)ethynyl)benzo[ i ]dipyrido[3,2- a :2′,3′- c ]phenazine and bpy = 2,2′-bipyridine have been synthesized. Their electrochemical and photophysical properties have been studied, with the aid of DFT and TD-DFT theoretical methods. The extended phenanthroline ligand PT exhibits two reduction processes at −0.98 and −1.55 (versus SCE) and no clearly detectable oxidation processes; the more extended analogue NT is substantially easier to reduce by about 300 mV. In the four complexes, the two first reduction processes are centered on the extended phenanthroline ligands, and, according to DFT calculations, also oxidations are likely to be located on such moieties. PT and NT exhibit green-yellow fluorescence at 298 and 77 K with photoluminescence quantum yields of 3.4% and 62.1%, respectively, at room temperature. At 77 K, a strong and long-lived phosphorescence is detected only for PT ( λ max = 658 nm, τ = 29 ms). In oxygen-free solution at 298 K [Ru(PT) 3 ] 2+ and [Ru(PT)(bpy) 2 ] 2+ exhibit a very weak emission band with λ max at about 700 nm, which extends towards the near infrared region and is unambiguously attributed to emission from the lowest triplet level centered on the PT ligand; its emission intensity is strongly enhanced at 77 K where lifetimes of 724 and 767 ns are measured for [Ru(PT) 3 ] 2+ and [Ru(PT)(bpy) 2 ] 2+ , respectively. The two complexes with the NT ligand show no triplet emission as observed for the PT analogues, but only a faint fluorescence signal attributable to negligible amounts of free ligand in solution. Photophysical data are fully rationalized with DFT methods, which always predict that the lowest triplet excited state is centered on the extended phenanthroline ligand in all of the investigated Ru II complexes. The estimated energy of the lowest triplet level of the PT-based compounds is in good agreement with the experimental value determined from the phosphorescence spectra. Moreover, the theoretical model rationalizes the lack of phosphorescence for the NT series, because the lowest triplet is estimated to be at 0.97 eV above the ground state (≈1280 nm), where non-radiative deactivations prevail. [ABSTRACT FROM AUTHOR]

Here we report our recent progresses in the synthesis and the study of fullerene-containing macromolecules. For example, poly(aryl ether) dendritic branches terminated with peripheral triethyleneglycol chains have been attached to C60. Their photophysical properties have been systematically investigated in three solvents, namely toluene, dichloromethane, and acetonitrile. The changes observed in the photophysical properties along the series suggest an increasing interaction between the poly(aryl ether) dendritic wedges and the fullerene core, which brings about an increasing isolation of the central chromophore towards the exterior. Finally, thanks to their high solubility, these fullerodendrimers have been easily incorporated in mesoporous silica glasses and measurements on the resulting doped samples have revealed efficient optical limiting properties. Fullerene-containing polyesters have also been prepared by polycondensation of a bifunctional fullerene adduct with tetraethyleneglycol. These polymers have been obtained in good yields and found to have quite high molecular weights. Thanks to their good solubility in common organic solvents and to their good film-forming properties, these fullerene-containing polyesters are easy to process and could be used to evaluate their potential for the preparation of all-polymer donor/acceptor bulk heterojunction photovoltaic cells. [Copyright &y& Elsevier]