Molecular and Low‐dimensional Coordination Compounds of Copper(II) and 3, 5‐Dimethylpyrazole — Synthesis, Crystal Structure, and Properties

Abstract

AbstractThree 3, 5‐dimethylpyrazole (pz*) copper(II) complexes, [Cu(pz*)4(H2O)](ClO4)2 (1), [Cu(pz*)2(NCS)2]·H2O (2), and [Cu(pz*)2(OOCCH=CHCOO)(H2O)]·1.5H2O (3), have been synthesized and characterized with single crystal X‐ray structure analysis. 1 crystallizes in the tetragonal space group, 14/m, with a = 14.027 (3) Å, c = 16.301 (5) Å, and Z = 4. 2 crystallizes in the monoclinic space group, P21/c, with a = 8.008 (3) Å, b = 27.139 (9) Å, c = 8.934 (3) Å, β = 106.345 (6)°, and Z = 4. 3 crystallizes in the triclinic space group, P1¯, with a = 7.291 (9) Å, b = 10.891 (13) Å, c = 11.822 (14) Å, α = 80.90 (2)°, β = 79.73(2)°, γ = 70.60(2)°, and Z = 2. In 1, one water molecule and four pz* ligands are coordinated to CuII. Two [Cu(pz*)4(H2O)]2+ units are connected to ClO4— via hydrogen bonds. One lattice water molecule is found in the unit cell of 2, which forms an one‐dimensional chain via intermolecular hydrogen bonds with the N‐H atom of pz*. In 3, the oxygen atom of the coordinated water molecule is connected with two C=O groups of two neighbouring maleic acid molecules to form a linear parallelogram structure. Another C=O group of maleic acid forms a hydrogen bond with the N‐H atom of pz* to create a two‐dimensional structure. The spectroscopic and bond properties are also discussed.