Crystallographic and computational study of 1-(arylamino)-1,2,3-triazole-4-carbohydrazides

Abstract

1 Graphical AbstractSystematic analysis reveals the influence of the aryl substituents upon the formation of supramolecular synthons based on N-H···N and N-H···O hydrogen bonding. AbstractCrystallography on mono-p-substituted derivatives of 1-(arylamino)-1,2,3-triazole-4-carbohydrazides, 1 (X = H), 2 (F), 3 (Cl) and 4 (Br), and a 2,5-dichloro (5) analogue, shows the molecular structures to be similar. Distinct hydrogen bonding patterns based on N-H···N and N-H···O are observed in their crystal structures with 1, having two independent molecules comprising the asymmetric unit, displaying one pattern, 2 and 5 another, and 3 and 4 yet another.Geometry optimisation calculations indicate any conformational differences in the solid-state do not persist in the gas-phase, and that no influence of the substituents is seen in the geometric parameters. A Natural Population Analysis, for both experimental and optimised structures, shows the charge on the triazole-N3 atom is at a maximum for 1, as opposed to 2-5, an observation correlated with its distinctive packing based around a supramolecular synthon not seen in the other structures. For the molecules having electronegative substituents, Molecular Electrostatic Potentials show the energies of the amine-H4n atoms are reduced for 2 and 5, compared to 3 and 4. A further distinction in 2-5 is indicated by the Hirshfeld surface analysis which highlights the importance of π···π interactions in 2 and 5, i.e. with the more electronegative substituents. Clearly, there is interplay between various factors but all correlated with the influence of the electronegativity of the substituent(s).

Structural systematics of aryl-1,3-dithiane derivatives: crystal and energy-minimised structures, and Hirshfeld surface analysis

“…The above notwithstanding, the differences in charges are typically less than 0.03 so that any effects are small. These conclusions match those found in related studies where the electronegativity of substituents in aryl rings in small organic molecules were systematically varied [12,13] …”

“…In this way, the influence of small perturbations in chemistry upon molecular packing can be determined. In keeping with this idea, an emphasis of recent work has been upon the monitoring of the effect of systematically changing the electronegativity of substituents in the aryl rings of two series small organic molecules [12,13]. For these series, significant electronic effects can be invoked to account for different molecular packing, but the participation of the substituents in specific interactions can also be crucial.…”

Strong piezoelectricity in [H-β-(2-pyridyl)-Ala-OH][BF4] and [H-β-(2-pyridyl)-Ala-OH][ClO4] – new amino acid based hybrid crystals

“…N-HÁ Á ÁO, O-HÁ Á ÁO and C-HÁ Á ÁO intermolecular interactions are crucial in building supramolecular architectures in organic-inorganic hybrids as well as metal-organic materials. [26][27][28] Oxygen from perchlorate ions acts as an acceptor in 7 different hydrogen bonds. Table 2 summarizes the hydrogen bond parameters whereas…”

Structural diversity in mercury(II) coordination complexes with asymmetrical hydrazone-based ligands derived from pyridine

“…Over the last few years bis(pyridyl)-2,3-diaza-1,3-butadiene has become a well-known ligating linker in coordination chemistry. In modern design of coordination architecture the role of all possible noncovalent interactions in self-assembly and supramolecular recognition have to be considered along with strong and weaker hydrogen bonds such as N-H…O/N [23][24], N-H…halogen [25], as well as the π…π interactions [26][27][28][29][30]. Furthermore, the presence of additional substituents in the central aliphatic linker, as well as the position of N atoms in the pyridyl rings, had significant influence on the resulting assembly of the coordination framework.…”