Ultraviolet and Visible Spectra of the Picrates of Polycyclic Aromatic Hydrocarbons and other Organic Compounds: A Method for Their Identification

Synthesis, crystal growth and characterization of a new organic NLO material: Caffeinium picrate (CAFP)—A charge transfer molecular complex salt

“…The spectrum exhibits a strong absorption band at 335.5 nm, which is attributed to pÀp* transition of picrate ion and no different bands due to an assumed charge transfer transition (the promotion of an electron from the highest occupied molecular orbital (HOMO) of the donor to the vacant molecular orbital (LUMO) of the acceptor) appear in the range 460-800 nm. To explain such a conclusion it has been thought that these labile complexes which are chromatographically decomposed could have disassociated from the reaction with pure hydroxylic solvent [28]. The absence of absorption above 400 nm is an advantage, as it is the prime requirement for materials having NLO properties.…”

Synthesis, spectroscopic studies and thermal analysis of charge-transfer complex of 2,2′-bipyridine with 4-hydroxybenzoic acid in different polar solvents

“…Molecular complexes of the donor-acceptor type formed between aromatic amines and p acceptors were the subject of extensive studies [34]. Recently, N-heterocyclic compounds were used as efficient donors in the preparation of CT complexes with different p acceptors [35,36]. Charge-transfer materials have become very important in recent years due to their efficiency in the field of magnetic, electrical and optical properties [37,38].…”

Dissociative Electron Attachment during the Laser Desorption of Anthracene Picrate

“…The absorption characteristics of the solid matrix is affected by the presence of anthracene. The absorption maxima observed in the spectra of the donor and acceptor components are barely altered on complexation . Thus the absorption of the charge-transfer complex will be dominated by the PAH which exhibits the more intense absorption band at 266 nm.…”

“…The absorption maxima observed in the spectra of the donor and acceptor components are barely altered on complexation. 6 Thus the absorption of the charge-transfer complex will be dominated by the PAH which exhibits the more intense absorption band at 266 nm. Hence, the desorption of picric acid into the gas phase may be greatly enhanced by the increased absorption properties of the sample, as anthracene exhibits a near resonance (S 3 r S 0 ) absorption at 252 nm.…”

“…Polycyclic aromatic hydrocarbons (PAHs) are known to form complexes with a variety of acceptor molecules including aromatic amines, − nitrobenzene derivatives, − and cyclodextrins . As part of a L2ToF mass spectrometric investigation of weakly bound molecular complexes, we have studied the laser desorption of the archetypal charge-transfer complex formed between anthracene and picric acid (2,4,6-trinitrophenol).…”