A series of highly organic -solu ble [ bis( tria I kylsi loxy) ] si I ico n tetra kis (a I ky It h io) -2,3nap ht halocya n i neshave been synthesized, and their 'H NMR, electronic absorption and fluorescence spectra measured. These spectra indicate that ( R',SiO),SiNc(SR2), are monomeric in solution (10-2-10-7 mol dm-,). In their solid films, all Q-band absorption maxima of ( R1,Si0),SiNc(SR2), are red-shifted from their monomeric Q-band maximum. The extent of shift significantly increases with decreasing R' length of the axial substituents, but the effect is far less with ring substituents, R2. These observations are clearly explained using the exiton model. Our results indicated that novel naphthalocyanine ( R',SiO),SiNc(SR2), molecules have a J-type molecular arrangement in thin solid films.* It is well known that J aggregates exhibit spectral red shifts (probably 'J' for Jelley, one of the lirst workers to investigate thcsc shifts), whereas the blue-shifted aggregates are designated iis 'H'aggregates ( H for hypsochromic).
. Can. J. Chem. 70, 2683Chem. 70, (1992.Methods of synthesis, elemental analyses, and IR and NMR spectroscopic data are reported for a series of triphenyltin esters of N-salicylidene-w amino acids of the general formula: Ph,SnOCO(CH?),,N=CHAr (Ar = 2-HOC6H4-and 2-HOCloH6-; n = 1, 2, 3, and 5). The crystal structure of triphenyltin N-sajicylidene-6-amin$exanoate was detedmined. The crystals are monoclini:, space group P2,/a, with a = 16.3493 (8) [Traduit par la redaction]
Photochemical reaction of substituted 1,4-naphthoquinones with 1,1-diarylethylenes led primarily to benz-[o]anthracene-7,12-dione derivatives. Evidence was obtained that the photoreaction proceeded via a photoinduced electron-transfer process. Extension of the reaction provided regioselective syntheses of other polycyclic aromatic quiñones.Polycyclic aromatic compounds have attracted much attention because of their physicochemical and biochemical properties.1 However, investigations of polycyclic aromatic compounds have been hampered by lack of general and facile regioselective synthetic routes to them.2 A facile route to A ring substituted benz[a]anthracene-7,12-diones was recently reported38 using the Diels-Alder reaction of
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