Crystal structure and Hirshfeld-surface analysis of di-aqua-bis-(5-methyl-1H-1,2,4-triazole-3-carboxyl-ato)copper(II).

The title compound, [Cu(HL)2(H2O)2] or [Cu(C4H4N3O2)2(H2O)2], is a mononuclear octa-hedral CuII complex based on 5-methyl-1H-1,2,4-triazole-3-carb-oxy-lic acid (H2 L). [Cu(HL)2(H2O)2] was synthesized by reaction of H2 L with copper(II) nitrate hexa-hydrate (2:1 stoichiometric ratio) in water under ambient conditions to produce clear light-blue crystals. The central Cu atom exhibits an N2O4 coordination environment in an elongated octa-hedral geometry provided by two bidentate HL - anions in the equatorial plane and two water mol-ecules in the axial positions. Hirshfeld surface analysis revealed that the most important contributions to the surface contacts are from H⋯O/O⋯H (33.1%), H⋯H (29.5%) and H⋯N/N⋯H (19.3%) inter-actions.

Synthesis and crystal structure of a new copper(II) complex based on 5-ethyl-3-(pyridin-2-yl)-1,2,4-triazole.

The title compound, bis-[µ-3-ethyl-5-(pyridin-2-yl)-1H-1,2,4-triazol-1-ido]bis[acetato-(di-methyl-formamide)-copper(II)], [Cu2(C9H9N4)2(C2H3O2)2(C3H7NO)2] or [Cu2(L Et)2(OAc)2(dmf)2], is a triazolate complex, which contains two 3-(2-pyrid-yl)-5-ethyl-triazolates (L Et)- in bidentate-bridged coordination modes. Both copper atoms are involved in the formation of a planar six-membered metallocycle Cu-[N-N]2-Cu. The inversion center of the complex is located at the mid-point of the Cu⋯Cu vector. Each CuII atom has a distorted trigonal-bipyramidal environment formed by the three nitro-gen atoms of the deprotonated bridging 3-(2-pyrid-yl)-5-ethyl-triazolate unit, oxygen atoms of the OAc- group and dmf mol-ecule. In the crystal, C-H⋯O hydrogen bonds link the mol-ecules into chains running along the c-axis direction.

Synthesis and crystal structure of hydrated µ-oxa-lato-bis-{bis-[3-methyl-5-(pyridin-2-yl)-1H-1,2,4-triazole]iron(II)} bis-(toluene-sulfonate) 2.75-hydrate.

In the title compound [Fe2(C2O4)(C8H8N4)4](CH3C6H4SO3)2·2.75H2O, the two FeII ions have a highly distorted octa-hedral FeN4O2 environment formed by two bidentate triazole-based chelating ligands and a bis-bidentate oxalate bridging anion that connects the metal ions. Stabilization within the crystal structure is provided via a system of O-H⋯O and N-H⋯O hydrogen bonding, which determines the formation of a two-dimensional architecture along the a-axis direction.

An investigation of two copper(ii) complexes with a triazole derivative as a ligand: magnetic and catalytic properties.

Two new copper(ii) complexes [Cu2(L)2(OAc)2(H2O)2] (1) (L = 3-methyl-5-pyridin-2-yl-1,2,4-triazole) and [CuL2] (2) were prerared and thoroughly studied. The complexes are able to selectively catalyze the oxidation of styrene towards benzaldehyde and of cyclohexane to KA oil. The 2D coordination polymer 1 showed an antiferromagnetic behaviour attributed to the intrachain magnetic coupling.