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The water mol­ecule connects the mol­ecules in the crystal packing. The crystal structure exhibits N—H⋯O, O—H⋯O and O—H⋯N inter­actions, resulting in the formation of a three-dimensional framework., In the mol­ecular structure of the title compound, C10H10N4O2·H2O, the angle between the triazole and arene rings is 87.39 (5)°. The water of crystallization connects the mol­ecules in the crystal packing. The crystal structure exhibits N—H⋯O, O—H⋯O and O—H⋯N inter­actions, resulting in the formation of a three-dimensional framework. The inter­molecular inter­actions were identified and qu­anti­fied using Hirshfeld surface analysis.

The crystallography of 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 that any conformational differences in the solid state do not persist in the gas-phase and that no influence of the substituents is seen on the geometric parameters. A natural population analysis, for both experimental and optimised structures, shows that 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 that 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).

In this work we report the synthesis, crystal structures, and magnetic behavior of 2p-3d-4f heterospin systems containing the nitroxide radical 4-azido-2,2,6,6-tetramethylpiperidine-1-oxyl radical (N3tempo). These compounds were synthesized through a one-pot reaction by using [Cu(hfac)2], [Ln(hfac)3] (hfac = hexafluoroacetylacetonate, Ln = Dy(III), Tb(III) or Gd(III)), and the N3tempo radical. Depending on the stoichiometric ratio used, the synthesis leads to penta- or trimetallic compounds, with molecular formulas [Cu3Ln2(hfac)8(OH)4(N3tempo)] (Ln = Gd, Tb, Dy) and [CuLn2(hfac)8(N3tempo)2(H2O)2] (Ln = Gd, Dy). The magnetic properties of all compounds were investigated by direct current (dc) and alternating current (ac) measurements. The ac magnetic susceptibility measurements of Tb(III)- and Dy(III)-containing compounds of both families revealed slow relaxation of the magnetization, with magnetic quantum tunneling in zero field.

A series of 13 D-gluconamides were synthesized in moderate to good yields and evaluated as green scale inhibitors. The crystal structures of two compounds were determined by X-ray crystallography. The compounds 6c and 6d showed a reasonable inhibition of BaSO(4) precipitation from aqueous solution (47% and 51%, respectively) that indicated the potential for these derivatives of δ-gluconolactone.

Two new magnetic copper compounds were obtained using the 4,4,4-trifluoro-1-furoylbutane-1,3-dione (Ftfac) ligand and two nitroxide radicals: 3-pyridyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (NITmPy) and 4-hydroxy-2,2,6,6-tetramethylpiperidinyl-N-oxy (Tempol). The complexes with formula [Cu(Ftfac)2(NITmPy)2] (1) and [Cu(Ftfac)2(Tempol)] (2) were structurally characterized by single-crystal X-ray diffraction. In compound 1, the copper ion has a distorted octahedral environment, bound to two NITmpPy ligands through the nitrogen atom of the pyridine ring. In compound 2, the copper ion has a distorted pyramidal environment in which the apical position is occupied by the oxygen atom of the Tempol hydroxyl group. The temperature dependence of the magnetic susceptibility of the two compounds was investigated. It was found that compound 1 presents ferromagnetic interaction (J = 9.1 cm−1) among copper(II) ions and NITmPy radicals. As a result of the interconnection between molecular moieties through H-bonds, compound 2 presents an unusual magnetic behavior with alternating ferro- and antiferromagnetic interactions.

Structural analysis reveals the presence of supramolecular chains in a series of eight N-arylamino 1,2,3-triazole esters, which differ only in the nature of the substituent (Y) of the terminal aryl ring. In each of 1 (Y = 4-H), 3 (4-Cl), 4 (4-Br), 5 (4-I) and 6 (4-OMe), the chains are sustained by N–H⋯N hydrogen bonding. In 2 (Y = 4-F) and 8 (Y = 2,5-Cl2), the chains are mediated by alternating N–H⋯N and N–H⋯O hydrogen bonding, whereas in 7 (Y = 4-NO2) the chain is sustained by N–H⋯O hydrogen bonding only. While the differences in the adopted supramolecular motifs are qualitatively correlated with the electronegativity of the Y substituents, no quantitative correlations could be made with the electronic structures of the theoretical gas-phase molecules. Two distinct patterns of crystal packing are observed, with the first of these being based on the inter-digitation of layers, comprised of supramolecular chains and connections of the type C–X⋯π(aryl) between them for 3–5 and 8; only weak off-set edge-to-edge π⋯π interactions were noted in the case of 1. A common feature of the zigzag chains in these crystal structures was a syn-disposition of successive aryl rings along the axis of propagation. The remaining structures adopted three-dimensional architectures where the Y substituents of the anti-disposed aryl rings participated in F⋯H (2) or C–H⋯O (6 and 7) interactions. A detailed analysis of the Hirshfeld surfaces and fingerprint plots for 1–8 enabled a comparison of the intermolecular interactions involved in constructing the disparate supramolecular architectures. In the structures featuring N–H⋯N hydrogen bonding leading to the supramolecular chain, the maximum contribution to the overall crystal packing was less than 20%. This increased to over 25% in the case where there was exclusive N–H⋯O hydrogen bonding in the chain.

The presence of localised C–X⋯π [or C–X⋯π(CC)] interactions are shown to be pivotal in the crystal structures of (5-methyl-1-(4-X-arylamino)-1H-1,2,3-triazol-4-yl)methanol derivatives, X = H (1), F (2) and Cl (3). In the absence of halide (1), molecules aggregate into supramolecular chains via alternating ten-membered {⋯HOC2N}2 and 14-membered {⋯HN2C3O}2 synthons. Molecules assemble into a three-dimensional architecture via edge-to-face C–H⋯π(arene) interactions occurring between the phenyl rings. In the presence of halide (i.e. F (2) and Cl (3) in the 4-position of the phenyl ring), two-dimensional arrays are formed by interconnected ten-membered {⋯HOC2N}2 (as seen in 1) and 24-membered {⋯HO⋯NC2OH⋯N4H}2 hydrogen bonded synthons. The latter arrangement allows for the close approach of halide to the 1,2,3-triazole ring and the formation of C–X⋯π interactions which appear to be particularly significant in the case of Cl (3), as evidenced by systematic changes (i.e. elongation) in the geometric parameters within the five-membered ring. In this series of structures, the presence of C–X⋯π interactions is shown to moderate the supramolecular aggregation based on conventional hydrogen bonding.