Two Cu(II) complexes of 3,4,5-tri­methyl-1H-pyrazole

The crystal structure of complexes of 3,4,5-tri­methyl-1H-pyrazole with CuCl(2)·2H(2)O and Cu(NO(3))(2)·2.5H(2)O are presented, namely di-μ-chlorido-bis[chloridobis(3,4,5-trimethyl-1H-pyrazole-κN (2))copper(II)], [Cu(2)Cl(4)(C(6)H(10)N(2))(4)] (1) and aquatetrakis(3,4,5-trimethyl-1H-pyrazole-κN (2))copper(II) dinitrate, [Cu(C(6)H(10)N(2))(4)(H(2)O)](NO(3))(2) (2), and compared to the previously determined structures for 3-methyl-1H-pyrazole and 3,5-di­methyl-1H-pyrazole. CuCl(2) forms a 2:1 ligand-to-metal chloride-bridged complex with 3,4,5-tri­methyl-1H-pyrazole, with a square-pyramidal coordination geometry about each copper(II) center. Similarly to the previously obtained 3,5-di­methyl-1H-pyrazole complex with CuCl(2), 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(NO(3))(2) forms a 4:1 ligand-to-metal complex with 3,4,5-tri­methyl-1H-pyrazole that is also arranged in a square-pyramidal geometry about Cu(II). The newly obtained copper(II) complex has the same coordination geometry as the 3,5-di­methyl-1H-pyrazole complex, including an axial water mol­ecule, two nitrate ions hydrogen-bonded to the water mol­ecule, and four pyrazole ligands in the equatorial plane, suggesting that similar steric forces are at play in the formation of these complexes.