Asunto(s)
Trasplante de Médula Ósea , Fracturas no Consolidadas/terapia , Adulto , Humanos , Masculino , Trasplante AutólogoRESUMEN
6,7-Bismethoxy-2,11-dihydroxytetraphenylene (1), a novel building block of tetraphenylene-derived macrocycles, was synthesized via palladium-catalyzed cross-coupling reactions and characterized by X-ray diffraction. The relevant macrocyclic hosts derived from 1 have well-defined structures with fixed conformations both in solution and solid state. They showed efficient and unique properties toward complexation with fullerenes C60 and C70 in toluene.
Asunto(s)
Fulerenos/química , Compuestos Macrocíclicos/química , Compuestos de Terfenilo/síntesis química , Catálisis , Cristalografía por Rayos X , Compuestos Macrocíclicos/síntesis química , Espectroscopía de Resonancia Magnética , Conformación Molecular , Paladio/química , Compuestos de Terfenilo/químicaRESUMEN
The FTIR, Raman and UV-vis spectra of the recently synthesized tetrathia[8]circulene and tetraselena[8]circulene compounds have been measured and interpreted in details by the density functional theory (DFT) calculations taking into account the molecular symmetry constrains. The structural and electronic features of the studied compounds have also been discussed in connection with the observed spectroscopic characteristics. Particularly, we have found that despite a slightly non-planar conformation the neutral tetrathia[8]circulene and tetraselena[8]circulene molecules demonstrate bifacial aromatic/antiaromatic nature. The inner octatetraene core is characterized by the presence of paratropic ("antiaromatic") ring currents, whereas the outer macrocycle constructed of benzene, thiophene or selenophene rings possesses the strong magnetically-induced diatropic ("aromatic") ring current. This fact suggests the general electronic and magnetic similarity of the tetrathia- and tetraselena[8]circulenes with the strictly planar isoelectronic tetraoxa[8]circulene and related azaoxa-derivatives discussed earlier. However, the vibrational and UV-vis absorption spectra of the studied circulenes are rather different from those of the parent tetraoxa[8]circulene which indicates a clear manifestation of the symmetry selection rules.
RESUMEN
Novel oxygen-, nitrogen-, sulfur-, and selenium-bridged tetraphenylenes were prepared from known tetraphenylene derivatives. Structures of these compounds were unambiguously confirmed by X-ray crystallographic analyses. Photophysical and electrochemical investigations of these heteroatom-bridged tetraphenylenes suggested their potential applications as electronic materials.