The role of non-covalent interactions in some 2-trifluoromethylchromones in the solid state

Abstract

Intermolecular interactions in chromone systems and criteria for the existence of C–H⋯F hydrogen bonds involving organic fluorine have been focused on in this work.

Synthesis, Experimental and Theoretical Study of Azidochromones

“…Moreover, the C7 (sp2) -H7•••F2 angle is nearly linear (173 • ), while the observed angle for C3 (sp3) -H3 •••F1 (107 • ) reveals a moderate angular directionality. In this sense, the d(H7•••F2) intermolecular distance (2.540 Å) is shorter than that observed in 3-bromomethyl-2-trifluoromethylchromone [3] and CF 3 /CF 2 H-substituted benzene, where the role of CF 3 /CF 2 H groups in the C-H•••F intermolecular interactions contributes significantly to the stability and molecular arrangement of the crystal structures (see Table S6, Supplementary Materials). While the C2 (sp3…”

“…The strong bands at 203 nm for 2 and 204 nm for 3-5 derive from electronic excitations from HOMO → LUMO + 5 (2) and HOMO − 2 → LUMO + 2 (3)(4)(5). The absorption at 203 nm (calc.…”

“…The absorption at 204 nm (3)(4)(5) is originated in all cases from π → π* transitions within the aromatic ring and to π*-orbitals of C=C and N2=N3 bonds.…”

“…Chromone derivatives with reactive functional groups such as halogens [1,2], haloalkyl [3][4][5], hydroxyl [6], amino [7,8] and azide [8,9] are important cores and precursors for pharmacologically active compounds (anti-cancer, anti-HIV, antioxidant, anti-tubercular, anti-inflammatory, analgesic, antimicrobial, anti-malaria, gastroprotective, antihistamine and antihypertensive) [10][11][12][13][14]. Among them, haloalkyl groups and azides are particularly relevant, both for their accessible synthetic routes and for their wide use as precursors of reactive species [15].…”