Molecular and low-dimensional coordination compounds of copper(II) and 3,5-dimethylpyrazole - Synthesis, crystal structure, and properties

Three 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)].1.5H(2)O (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) Angstrom, c = 16.301 (5) Angstrom, and Z = 4. 2 crystallizes in the monoclinic space group, P2(1)/c, with a = 8.008 (3) Angstrom, b = 27.139 (9) Angstrom, c = 8.934 (3) Angstrom, beta = 106.345 (6)degrees, and Z = 4. 3 crystallizes in the triclinic space group, P (1) over bar, with a = 7.291 (9) Angstrom, b = 10.891 (13) Angstrom, c = 11.822 (14) Angstrom, alpha = 80.90 (2)degrees, beta = 79.73(2)degrees, gamma = 70.60(2)degrees, and Z = 2. In 1, one water molecule and four pz* ligands are coordinated to Cu-II. 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.