Synthesis and Physicochemical Characterization of Protonated and Deprotonated Forms in Heteroleptic Lanthanide(III) Porphyrinate Double-Deckers. X-ray Structure of GdIIIH(oep)(tpp) at 298 a

详细信息    查看全文

• 作者：Georgios A. Spyroulias ; Catherine P. Raptopoulou ; Dominique de Montauzon ; Alain Mari ; René ; Poilblanc ; Aris Terzis ; and Athanassios G. Coutsolelos
• 刊名：Inorganic Chemistry
• 出版年：1999
• 出版时间：April 19, 1999
• 年：1999
• 卷：38
• 期：8
• 页码：1683 - 1696
• 全文大小：366K
• 年卷期：v.38,no.8(April 19, 1999)
• ISSN：1520-510X

文摘

The synthesis, spectroscopic characterization, and electrochemical study of eleven heteroleptic and theircorresponding homoleptic lanthanide sandwiches are reported. Studies in solution have been carried out in solventsof different basicity, in order to elucidate the equilibrium between the protonated and deprotonated form of thesecomplexes. The investigated compounds are represented by the formulas Ln^IIIH(oep)(tpp) and [Ln^III(oep)(tpp)]^-corresponding to the protonated and deprotonated forms, respectively (in the case of heteroleptic), and the formulasLn^IIIH(tpp)₂ and [Ln^III(tpp)₂]^- (in the case of the homoleptic porphyrin double-deckers), where Ln Nd, ..., Lu(except Pm), oep = 2,3,7,8,12,13,17,18-octaethylporphyrinate, and tpp = 5,10,15,20-tetraphenylporphyrinate).Various spectroscopic methods are used for the physicochemical characterization of the title complexes. Theelectronic spectra of the complexes above present different features in CH₂Cl₂ and in DMF. In the latter solventthey reveal features similar to those of the analogous actinide(IV) porphyrin double-decker. The electrochemicalstudies carried out in CH₂Cl₂ and THF demonstrate clearly that the redox behavior of the double-deckers,heteroleptic or homoleptic, is strongly dependent on the proton on the porphyrinic core. In CH₂Cl₂, four reversibleoxidation processes and two quasi-reversible waves are observed for the protonated species in both homo- andheteroleptic double-deckers. In contrast, two oxidations and two reductions are observed in THF for the homolepticderivatives, while the corresponding heteroleptic ones undergo three oxidations and one reduction process. Thestructure of the new heteroleptic double-decker Gd^IIIH(oep)(tpp) was determined by X-ray diffraction at 298 and21 K. Both structures are compared with the first analogous structure of Sm^IIIH(oep)(tpp). According to thespectroscopic and structural data reported for the heteroleptic protonated derivatives, the oep macrocycle is thefavored binding site of the proton in solutions as well as in the solid state.