IR analysis of the carboxylate forms in structurally determined [CuII(κ3-L)2] species isolated from different acidic solutions

Abstract

Several copper(II) coordination compounds with the tridentate κ 3 -N,N,O bisligand (L = bis(3,5-dimethylpyrazol-1-yl)acetate or its molecular acid form HL = Hbdmpza) were synthesized from different starting metal salts in appropriate acidic water solutions as reported.

Copper-Based Complexes with Adamantane Ring-Conjugated bis(3,5-Dimethyl-pyrazol-1-yl)acetate Ligand as Promising Agents for the Treatment of Glioblastoma

“…Similarly, the planes passing through the acetylamido linker and each pyrazolyl ring makes with equatorial plane angles of 90 and 44.5°, respectively. A search in the CCDC repository , showed some Cu­(II) complexes of bis-pyrazolyl acetate, − among which few bis-pyrazolyl acetamide derivatives; other bis-pyrazolyl acetamide ligands, including the one present in the above-named aluminum complex are also known. − With one exception, reported bis-pyrazolyl acetate copper derivatives share a trans-fac coordination of the tridentate ligand with mean values of the O–Cu–O and O–Cu–N angles of 179.7 and 94.8°, similar to those found in this work. Likewise, the mean values of the Cu–N and Cu–O bonds are 2.055 and 2.276 Å; in 3 these bonds are 0.035 and 0.070 Å shorter than such means, respectively, but within the known ranges (1.972–2.438 Å for Cu–N and 1.936–2.540 Å for Cu–O).…”

“…Likewise, the mean values of the Cu–N and Cu–O bonds are 2.055 and 2.276 Å; in 3 these bonds are 0.035 and 0.070 Å shorter than such means, respectively, but within the known ranges (1.972–2.438 Å for Cu–N and 1.936–2.540 Å for Cu–O). Distances within pyrazolyl rings agree with those of known complexes, − as well as those of similar compounds recently investigated by our group . The C1–O1 bond (1.231(4) Å) and the C1–C2 bond (1.549(4) Å) have in turn elongated double-bond and single-bond character, giving no evidence of conjugation outside the pyrazolyl rings.…”