New CuI complexes of the Schiff‐base‐containing triazole ligands N‐[(E)‐(4‐chlorophenyl)methylidene]‐4H‐1,2,4‐triazol‐4‐amine (ClPhtrz) and N‐[(E)‐phenylmethylidene]‐4H‐1,2,4‐triazol‐4‐amine (Phtrz) have been synthesised and characterised. Depending on the reaction conditions ClPhtrz forms two different dimeric complexes 1 and 2. X‐ray crystallography revealed that each copper centre exhibits a planar trigonal coordination in 1, while the tetrahedral coordination sphere of the copper centre in 2 is completed by a solvent molecule. In dimeric complex 3 the tetrahedral coordination of the CuI ions is formed by two monodentate and two bidentate (bridging) Phtrz ligands. Complexes 1−3 are unstable and easily lose coordinating and/or solvating acetonitrile molecules giving 4 (from 1 and 2) and 5 (from 3). On the basis of ESI MS and 1H NMR and UV/Vis spectroscopy, it was shown that dimeric complexes 1−5 do not survive upon dissolution and dissociate rapidly forming mainly a 1:2 monomeric complex, along with a minor 1:1 complex. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

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.

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