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. 2018 Feb 16;74(Pt 3):357-362.
doi: 10.1107/S2056989018002359. eCollection 2018 Mar 1.

Two CuII complexes of 3,4,5-tri-methyl-1 H-pyrazole

Collin J Vincent  1 , Ian D Giles  2 , Jeffrey R Deschamps  2
Affiliations

Two CuII complexes of 3,4,5-tri-methyl-1 H-pyrazole

Collin J Vincent et al. Acta Crystallogr E Crystallogr Commun. .

Abstract

The crystal structure of complexes of 3,4,5-tri-methyl-1H-pyrazole with CuCl2·2H2O and Cu(NO3)2·2.5H2O are presented, namely di-μ-chlorido-bis[chloridobis(3,4,5-trimethyl-1H-pyrazole-κN2)copper(II)], [Cu2Cl4(C6H10N2)4] (1) and aquatetrakis(3,4,5-trimethyl-1H-pyrazole-κN2)copper(II) dinitrate, [Cu(C6H10N2)4(H2O)](NO3)2 (2), and compared to the previously determined structures for 3-methyl-1H-pyrazole and 3,5-di-methyl-1H-pyrazole. CuCl2 forms a 2:1 ligand-to-metal chloride-bridged complex with 3,4,5-tri-methyl-1H-pyrazole, with a square-pyramidal coordination geometry about each copper(II) center. Similarly to the previously obtained 3,5-di-methyl-1H-pyrazole complex with CuCl2, the pyrazole ligands are cis to each other, with two chloride ions bridging the two copper(II) centers, and a terminal chloride ion occupying the axial position. Cu(NO3)2 forms a 4:1 ligand-to-metal complex with 3,4,5-tri-methyl-1H-pyrazole that is also arranged in a square-pyramidal geometry about CuII. The newly obtained copper(II) complex has the same coordination geometry as the 3,5-di-methyl-1H-pyrazole complex, including an axial water mol-ecule, two nitrate ions hydrogen-bonded to the water mol-ecule, and four pyrazole ligands in the equatorial plane, suggesting that similar steric forces are at play in the formation of these complexes.

Keywords: chloride; complex; copper(II); crystal structure; metal organic; nitrate; tri­methyl­pyrazole.

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Figures

Figure 1
Figure 1
Mol­ecular structure of 1, showing the atom-labeling scheme. Displacement ellipsoids are drawn at the 50% probability level. The complex resides on an inversion center, with half of the mol­ecule generated by the symmetry operator −x, 1 − y, 1 − z. Only one set of disordered methyl protons are shown. Hydrogen-atom labels are omitted for clarity.
Figure 2
Figure 2
Mol­ecular structure of 2, showing the atom-labeling scheme. Displacement ellipsoids are drawn at the 50% probability level. Only one set of disordered methyl protons are shown. The Cu—OH2 bond resides on a twofold rotation axis, with half of the mol­ecule generated by the symmetry operator formula image − x, y, 1 − z. Hydrogen-atom labels are omitted for clarity.
Figure 3
Figure 3
Packing of 1 viewed down the crystallographic b-axis direction, highlighting the alignment of the copper complexes in the same orientation throughout the crystal. Hydrogen atoms are omitted for clarity.
Figure 4
Figure 4
Packing of 2 viewed down the crystallographic c-axis direction, highlighting the alternating columns of stacked copper complexes. Hydrogen atoms are omitted for clarity.
See this image and copyright information in PMC

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