One-pot cocrystallization of 1D linear and zigzag cobalt(II) polymers assembled by triclopyr and 4,4′-bipyridine: Structural comparison, conformational analysis, non-covalent interactions as well as the magnetic property of the latter

Abstract

A pair of cobalt(II) compounds with formulas of [Co(3,5,6-tcpa)2(4,4′-bipy)(EtOH)]n (1A) and [Co(3,5,6-tcpa)2(4,4′-bipy)(EtOH)2]n (1B), have been cosynthesized through the solvothermal reaction of cobalt chloride hexahydrate with triclopyr (systematic name 2-((3,5,6-trichloropyridin-2-yl) oxy)acetic acid, abbreviation 3,5,6-Htcpa) and 4,4′-bipyridine (4,4′-bipy) coligands. Single-crystal X-ray diffraction analysis indicated that complex 1A has orthorhombic system, space group Aea 2 (no. 41), while 1B showed monoclinic system, space group I2/a (no. 15). Compound 1A displays a 1D linear chain but 1B presents a zigzag chain, and 3,5,6-tcpa anion are both unidentate between them. The non-covalent interactions of CH···O/CH···Cl hydrogen bonds and Cl···O/ Cl···Cl halogen bonds undertake a significant role in their 3D molecule packing, which have been further verified by the careful Hirshfeld surface analyses. Based on the deeply structural comparisons, it was supposed that conformational flexibility of 3,5,6-tcpa might be responsible for the cocrystallization of 1A and 1B. Besides, the magnetic determinations revealed weak antiferromagnetic interactions for intrachain cobalt(II) ions in 1B.