Nm In DMF Research Articles

Spectral Evidences for the J-Aggregate Formation of a Non-Benzenoid Aromatic Dye, Dicyclohepta[5,6:b]pyrazino[2,3-g]quinoxaline-3,11-dione

Abstract The planar and symmetrically conjugated π-system, dicyclohepta[5,6:b]pyrazino[2,3-g]quinoxaline-3,11-dione, showed a narrow and intense absorption band and resonance fluorescence in cone H2SO4 solutions as low as 10−7 M. These observations show the formation of the J-aggregate. A remarkable solvatochromism was also noticed in organic solvents (476 nm in CHCl3 and 547 nm in DMF).

Squarilium dyes, their infrared and resonance Raman spectra and possible use in redox reactions for solar-energy conversion

Infrared and resonance Raman spectra of squarilium dyes I–VI of the type [graphic omitted] are presented and some vibrational modes of the central 4-membered ring are assigned. Methyl viologen dication (MV2+) is reduced photocatalytically by IV in DMSO + H2O (95/5, v/v) with a quantum yield ϕ of (1.8 ± 0.4)× 10–3 at 406.7 nm, if EDTA is present. Oxidation products of MV2+ behave similarly with ϕ=(4.7 ± 0.6)× 10–2 at 457.9 nm in DMF + H2O (2/1, v/v). IV˙+ seems to oxidize H2O nearly reversibly.