However, they are not consistent because different aromaticity values derived from different indices lead to different aromaticity orders. The suitability of the NICS and some other approaches for the prediction of aromaticity has also been questioned. Aromaticity follows Hückel's 4n+2 (n=0, 1,...
However, in pyrrole, the nonbonded electron pair on nitrogen is part of the aromatic 6p- electron sextet and is not available for NH salt formation, since this would generate an aliphatic (highly reactive) diene imminium cation, which would destroy pyrrole's aromaticity. However, electrophilic ...
(pKb13.6); On the contrary, combination of hydrogen on the nitrogen atom is weak acid. In addition, pyrrole ring with benzene and other aromatic compounds are same, it can conduct nitration, sulfonation, diazo coupling reaction, Friedel-Crafts type acylation. This reaction can get 2-substituted...
Face-to-face molecular packing was not observed in the crystals of either TPM or TPM-Cl. This packing mode effectively avoids the ACQ effect caused by strong π–π interactions from large planar structures. The distances between the aromatic rings were all >3.6 Å (4.058–7.550 Å)...
(SubP) have been extensively developed as an very attractive class of functional dyes owing to the interesting bowl-shaped curved structures, unique 14π-aromatic macrocycles and excellent physicochemical properties (Fig. 1)[5,6]. In 1972, Meller and Ossko first accidentally discovered the SubPcs...
Indeed, aromatic amines and several of their derivatives are known to form covalent bonds with DNA nucleobases34,35. This hypothesis is also consistent with the previously reported ability of acetanilide derivatives to form covalent DNA adducts, as in the study by Rogers on paracetamol36, where ...
A, B, A1and A2as aryl radicals include both aromatic and heteroaromatic radicals. Radicals which are particularly suitable as A, B, A1and A2include radicals of the formula ##STR6## wherein R1and R2are each independently of the other hydrogen, halogen, C1-C18alkyl, C1-C18alkoxy, C1-C18al...
It was assumed that the pyrrole ring can play a role as core moiety to interact with the aromatic residues of the AChE binding pocket while different substitutions on the ring might improve its potencies. In this context, a library of 39 molecules was designed and synthesized to properly evalu...
Electron-deficient π-conjugated functional dyes lie at the heart of organic optoelectronics. Adding nitro groups to aromatic compounds usually quenches their fluorescence via inter-system crossing (ISC) or internal conversion (IC). While strong electron
The ground state properties showed that there exist minimum pi-pi interaction between the aromatic subunits of these D-A systems. Quenched emission was observed in both the dyads when excited at 290 nm. The quenched emission explained in terms of intramolecular excitation energy transfer competes ...