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Copper complexes with organic ligands. II. Chemistry of ο-cresotinatocopper(II) complexes

J. Krätsmár-Šmogrovič, O. Hulková, B. Lučanská, and M. Bláhová

Komenský University, Bratislava

Abstract: cf. preceding abstr. The o-cresotinatocopper(II) complexes were studied by preparative and spectrophotometric methods. Cu₂A₄(H₂O)₃ complex (I) (HA is o-cresotinic acid) was isolated from the system Cu²⁺ - A^- - H₂O according to reaction: 2[Cu^-(H₂O)₄]₂⁺ + 4A^- → Cu₂A₄(H₂O)₃ + 5H₂O. I is also formed by the interaction of ο-cresotinate ions on the equil. system of salicylatocopper(II) (HSal is salicylic acid) complexes contg., in aq. acid soln., the dihydrate of the bis(salicylato)diaquocopper-(11) complex. The binding of ο-cresotinate ions to Cu(II) complex is more stable than that those of salicylatocopper(II) complex ions. This is also true in the system of bis(salicylato)diaquocopper(II) complex-HA-EtOH, from which Cu₂A₄(H₂O)^-(EtOH) (II) was isolated according to reaction: 2[CuSal₂)(H₂O)₂] + 4HA + EtOH → Cu₂A₄(H₂O)(EtOH) + 4HSal + 3H₂O. The study of the partial decompn. of I and II by heating for 10 h. at 100° and 20-30 torr has shown that the mol. ligands H₂O and EtOH are more stable in the ο-cresotinate complex than in the salicylate complex. The ο-cresotinic acid was formed by the cleavage of a part of the bound ο-cresotinate ions. By the complete thermal decompn. of I, a well defined new compd. in the form of a chelate-forming ligand was detd. according to reaction: Cu₂(A₄)₄(H₂O)₃ → Cu₂(MeC₆H₃OCO₂)A₂ + HA + 3H₂O.

Full paper in Portable Document Format: 1912a892.pdf (in Slovak)

Chemical Papers 19 (12) 892–899 (1965)