Construction of Zn(II) Linear Trinuclear Secondary Building Units from A Coordination Polymer Based on α-Acetamidocinnamic Acid and 4-Phenylpyridine

The synthesis and characterization of one coordination polymer and two trinuclear complexes are presented. The coordination polymer [Zn(2)(µ-O,O’-ACA)(2)(ACA)(2)(4-Phpy)(2)](n) (1) has been obtained by the reaction between Zn(OAc)(2)·2H(2)O, α-acetamidocinnamic acid (HACA), and 4-phenylpyridine (4-Phpy) using EtOH as solvent. Its recrystallization in CH(3)CN or EtOH yields two trinuclear complexes, both having pinwheel arrays with formulas [Zn(3)(µ-ACA)(6)(4-Phpy)(2)]·4CH(3)CN (2·4CH(3)CN) and [Zn(3)(µ-ACA)(6)(EtOH)(2)]·4EtOH (3·4EtOH), respectively. These trinuclear species, unavoidably lose their solvent co-crystallized molecules at RT yielding the complexes [Zn(3)(µ-ACA)(6)(4-Phpy)(2)] (2) and [Zn(3)(µ-ACA)(6)(EtOH)(2)] (3). In addition, compound 2 has also been obtained reacting Zn(OAc)(2)·2H(2)O, HACA, and 4-Phpy in a 1:2:2 ratio using CH(3)CN as solvent. Compounds 1–3 have been characterized by analytical and spectroscopic techniques. Furthermore, single crystals suitable for X-ray diffraction method for compounds 1, 2·4CH(3)CN, and 3·4EtOH were obtained and their supramolecular interactions have been studied and discussed, showing 2D supramolecular planes for the trinuclear complexes and a 3D supramolecular network for the coordination polymer. Finally, the supramolecular interactions of 2·4CH(3)CN and 3·4EtOH have been compared using Hirshfeld surface analysis and electrostatic potential calculations.