Dominant Role of C−Br···N Halogen Bond in Molecular Self-Organization. Crystallographic and Quantum-Chemical Study of Schiff-Base-Containing Triazoles

Abstract

Three Schiff-base-containing triazole derivatives have been synthesized and investigated by X-ray crystallography. Structural motifs (zigzag or linear chains) formed in the solid state are stabilized by C-Br‚‚‚N halogen bond interactions, while hydrogen bonds do not seem to play a significant role in the molecular self-organization of studied compounds. Quantum-chemical studies confirm that these interactions are sufficient to account for both the arrangement of structural motifs and very short Br‚‚‚N distances observed experimentally. It is also shown that Br‚‚‚N interactions can lead to generally shorter donor-acceptor distances than Cl‚‚‚N contacts.

Structural, electronic, and optical properties of crystalline iodoform under high pressure: A first-principles study

“…ular interactions, such as hydrogen bonds (A-H · · · B) and halogen bond (halogen · · · halogen). [20][21][22][23][24][25] It is demonstrated that these interactions play an important role in the formation of crystal structures, crystal packing, protein folding, and biological materials. 23,25 Several studies have reported the significant effect of pressure on enhancing molecular aggregates and controlling the strength of C-H · · · X (X = F, Cl, Br, and I) and halogen · · · halogen interactions.…”

“…[20][21][22][23][24][25] It is demonstrated that these interactions play an important role in the formation of crystal structures, crystal packing, protein folding, and biological materials. 23,25 Several studies have reported the significant effect of pressure on enhancing molecular aggregates and controlling the strength of C-H · · · X (X = F, Cl, Br, and I) and halogen · · · halogen interactions. 24,26,27 To obtain further information about pressure effect on weak interactions of C-H · · · X and halogen · · · halogen, we study the polyhalomethane iodoform at various pressures by means of first-principles calculations.…”

Molecular Assemblies from Imidazolyl‐Containing Haloalkenes and Haloalkynes: Competition between Halogen and Hydrogen Bonding

“…The diiodine basicity of imidazoles has been measured by means of the formation constant of diiodine-imidazole complexes in heptane at 298 K, [25] but the structural characterization of architectures sustained by halogen bonding in which imidazolyl groups are involved has not been reported. C-halogen···N interactions have been observed by X-ray crystal studies of Schiff-base-containing triazoles and 5-bromotetrazole, [26,27] but such interactions are overpowered by hydrogen bonding in the solid-state structures of 3-chloro-1H-1,2,4-triazole and 3-bromo-1H-1,2,4-triazole. [28] The electron-poor portion of the charge-transfer complex is generally an electron-deficient organic halide, and so 1,4-diiodotetrafluorobenzene has been used quite extensively.…”

“…Also, these compounds are good models for future computational stud-ies. The approach followed herein is similar to that chosen by Czugler, [17] van der Boom, [23] Drabent, [26] and others, [47] namely, the acceptor and donor sites are present in the same molecule. By employing this approach, the chances for disturbance by competing interactions are at a minimum.…”

Directionality and site selectivity of N⋯Cl halogen bonding in two azaaromatic chloride crystals

“…Very recently, a new kind of supramolecular interaction, namely the lone pairÁ Á Áp interaction, has been considered to construct supramolecular framework [5], that is a type of noncovalent interaction between atoms that contain lone pair electron and electron-deficient p-ring [6]. Halogen bonding is also a ''new" intermolecular interaction [7] that has attracted great interest in recent years [2,3,[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. It is an analogue of hydrogen bonding and is also used in crystal engineering to construct a variety of architectures [23][24][25][26][27].…”