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Mandal SK Samanta S Itkis ME Jensen DW Reed RW Oakley RT Tham FS Donnadieu B Haddon RC 《Journal of the American Chemical Society》2006,128(6):1982-1994
We report the preparation, crystallization, and solid-state characterization of the first two members of a new family of spiro-bis(1,9-disubstituted phenalenyl)boron neutral radicals based solely on oxygen functionalization, and we show that this strategy significantly lowers the electrochemical disproportionation potentials (DeltaE), in comparison with other spiro-bis(1,9-disubstituted phenalenyl)boron salts. In the solid state, these radicals pack in a continuous array of pi-pi-stacked phenalenyl units with very short intermolecular carbon...carbon contacts. These two radicals are among the most highly conducting neutral organic solids, with room temperature conductivities reaching 0.3 S/cm. Magnetic susceptibility measurements show that the radicals do not exist as isolated free radicals, and there is significant spin-spin interaction between the molecules in the solid state as expected from the crystal structures and the calculated band structures; the solid-state properties are best rationalized in terms of the resonating valence bond model. 相似文献
125.
Bhadra S Adak L Samanta S Maidul Islam AK Mukherjee M Ranu BC 《The Journal of organic chemistry》2010,75(24):8533-8541
An easily accessible catalyst, alumina-supported copper(II), efficiently catalyzes the ring opening of aziridines and epoxides followed by cyclization of the corresponding intermediate to produce a variety of functionalized 1,4-benzoxazines and 1,4-benzodioxanes, respectively, in one pot without any ligand in high yields. The ring cleavages of aziridines and epoxides are highly regioselective. The catalyst is inexpensive, non-air-sensitive, environmentally friendly, and recyclable. The function of the catalyst and the reaction pathway are postulated. This protocol is successfully utilized for the formation of three carbon-heteroatom bonds, namely, C-O, C-N, and C-S, in one pot. 相似文献
126.
K.C. Majumdar Srikanta Samanta Raj Kumar Nandi Buddhadeb Chattopadhyay 《Tetrahedron letters》2010,51(29):3807-3810
Palladium-catalyzed IBX-induced intramolecular oxidative amination of alkenes has been utilized for the synthesis of pyrrolocoumarin and pyrroloquinolone derivatives in excellent yields in a short reaction time. 相似文献
127.
Tushar Kanti Chakraborty Rajarshi Samanta Balasubramanian Sridhar 《Tetrahedron letters》2009,50(26):3306-1712
Ti(III)-mediated radical cyclization of β-aminoacrylate containing 2,3-epoxy alcohol moieties led to the formation of highly substituted piperidine and pyrrolidine rings. The pyrrolidine ring system was then transformed into an indolizidine framework present in many natural products. 相似文献
128.
Two efficacious synthetic methodologies for the construction of medium-sized nitrogen heterocycles dibenzoazocinones have been developed. The phosphine-assisted protocol afforded better yields of the dibenzoazocinones (73-82%). 相似文献
129.
P. Chenchanna V. K. Krishnankutty A. Mukherjee M. Samanta 《Experimental Mechanics》1970,10(3):130-132
An extensometer, designed on the resonance principle, suitable for the measurement of large extensions, is described. The experimental results obtained with such an instrument is discussed. 相似文献
130.