Solvent effects on the crystallization and structure of ternary copper(ii) coordination compounds with l-threonine and 1,10-phenanthroline.

Solution-based and solid-state reactions of copper(ii) compounds, 1,10-phenanthroline and l-threonine were investigated. Eight new ternary coordination compounds were obtained: [Cu(l-Thr)(H ₂ O)(phen)] ₂ SO ₄ ∙10H ₂ O ( 1a∙10H ₂ O ), [Cu(l-Thr)(H ₂ O) (phen)] ₂ SO ₄ ∙4.3H ₂ O ( 1a∙4.3H ₂ O ), {[Cu( μ -l-Thr)(phen)] ₂ SO ₄ ∙3.5H ₂ O} _n ( 1b∙3.5H ₂ O ), [Cu(l-Thr)(H ₂ O)(phen)][Cu(l-Thr)(CH ₃ OH)(phen)]SO ₄ ∙2H ₂ O∙CH ₃ OH ( 1c∙2H ₂ O∙CH ₃ OH ), [Cu(l-Thr)(H ₂ O)(phen)][Cu(l-Thr)(CH ₃ OH)(phen)]SO ₄ ∙4H ₂ O ( 1c∙4H ₂ O) , [Cu(l-Thr)(CH ₃ OH)(phen)] ₂ SO ₄ ∙H ₂ O ( 1d∙H ₂ O ), [Cu(l-Thr)(H ₂ O)(phen)][Cu(l-Thr)(CH ₃ OH)(phen)][Cu(SO ₄ )(l-Thr)(phen)]HSO ₄ ∙H ₂ O∙3CH ₃ OH ( 1e·H ₂ O·3CH ₃ OH ), [Cu(l-Thr)(H ₂ O)(phen)][Cu(l-Thr)(phen)(py)]SO ₄ ( 1f ) (phen = 1,10-phenanthroline, l-Thr = l-threoninate, py = pyridine). X-ray crystal structure analysis of the prepared ternary coordination compounds revealed extensive hydrogen bonding and π-interactions that link complex species, anions and solvent molecules into 3D architectures. The water/methanol solvent molecules are found in pockets and/or channels in seven solvates. ESR spectra of different types of compounds were also investigated. In all measured compounds the unpaired electron of the copper(II) ion is located in the d _x2-y2 orbital which is in agreement with elongated square-pyramidal geometry. Compound 1a∙10H ₂ O showed substantial cytotoxic activity toward human hepatocellular carcinoma (HepG2) and acute monocytic leukaemia (THP-1) cell lines.
Competing Interests: The authors declare no conflict of interest.
(© 2022 The Author(s).)