Structural and Optical Properties of New 2-Phenylamino-5-nitro-4-methylopyridine and 2-Phenylamino-5-nitro-6-methylpyridine Isomers.

ABSTRACT: Two new 2-N-phenylamino-5-nitropyridine-4-methyl (2PA5N4MP) and 2-N-phenylamino-5-nitropyridine-6-methyl (2PA5N6MP) isomers were synthesized and comprehensively characterized by single-crystal X-ray diffraction, IR/Raman spectroscopy, UV-Vis absorption, and photoluminescence measurements. DFT and TD-DFT calculations were also carried out to support the experimental results. The X-ray analysis revealed significant structural differences: 2PA5N6MP adopted an almost planar conformation (pyridine-phenyl dihedral ~3°), whereas 2PA5N4MP was markedly twisted (~45°), leading to distinct hydrogen-bonding motifs (N-H⋯N dimers vs. N-H⋯O interactions). These geometric disparities influenced their electronic properties: 2PA5N6MP exhibited a narrower HOMO-LUMO gap (≈2.45 eV) than 2PA5N4MP

SUBMITTER: Godlewska P 

PROVIDER: S-EPMC12692667 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature