Copper_(II) carboxylates with 2-aminopyridine. Synthesis, characterization and a study of the dimer-monomer equilibrium in acetonitrile solutions by VIS-spectroscopic and microcalorimetric titrations

Author(s)

Nina Lah, Gerald Giester, Jurij Lah, Primoz Segedin, Ivan Leban

Abstract

A series of copper_(II) carboxylates with 2-aminopyridine was prepared. In all cases typical dinuclear complexes with a paddle-wheel type structure, Cu₂X₄L₂, as well as mononuclear complexes of type CuX₂L₂ were obtained (X = hexanoate, heptanoate, octanoate or nonanoate, L = 2-aminopyridine). The structures of monoclinic Cu₂(O₂CC₇H₁₅)₄(C₅H₆N₂)₂, 1, and Cu(O₂CC₇H₁₅)₂(C₅H₆N₂)₂, 2, were determined by X-ray diffraction. VIS-absorption spectroscopic and isothermal calorimetric titrations, were employed to investigate the dimer–monomer equilibrium in acetonitrile solutions. The results were analysed on the basis of the mass-action model to obtain the equilibrium constants of monomer formation (K_M ≈ 10⁴ L mol⁻¹). The thermodynamic analysis shows that for all studied systems monomer formation is an enthalpy-driven process (ΔH_M° ≈ −14 kJ mol⁻¹). The observed exothermic ΔH_M° values result most likely from the attractive coordinative interactions between Cu²⁺ ion and 2-aminopyridine.

Organisation(s)

Department of Mineralogy and Crystallography

External organisation(s)

University of Ljubljana

Journal

New Journal of Chemistry

Volume

25

Pages

753-759

No. of pages

7

ISSN

1144-0546

DOI

https://doi.org/10.1039/b009807h

Publication date

2001

Peer reviewed

Yes

Austrian Fields of Science 2012

1051 Geology, Mineralogy

Portal url

https://ucrisportal.univie.ac.at/en/publications/copperii-carboxylates-with-2aminopyridine-synthesis-characterization-and-a-study-of-the-dimermonomer-equilibrium-in-acetonitrile-solutions-by-visspectroscopic-and-microcalorimetric-titrations(38c164f1-7577-49db-88cd-7cc004fd3c0a).html