Collin J Vincent1, Ian D Giles2, Jeffrey R Deschamps2. 1. Department of Chemistry, Washington College, 300 Washington Ave., Chestertown, MD 21620, USA. 2. CBMSE, Code 6910, U. S. Naval Research Laboratory, 4555 Overlook Ave, SW, Washington, DC 20375, USA.
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.
The crystal structure of complexes of 3,4,5-tri-methyl-1H-pyrazole with n class="Chemical">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-metalchloride-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.
Entities:
Keywords:
chloride; complex; copper(II); crystal structure; metal organic; nitrate; trimethylpyrazole
Authors: Tyler J Morin; Sarath Wanniarachchi; Chengeto Gwengo; Vitales Makura; Heidi M Tatlock; Sergey V Lindeman; Brian Bennett; Gary J Long; Fernande Grandjean; James R Gardinier Journal: Dalton Trans Date: 2011-07-01 Impact factor: 4.390