Investigations of stable penta- and hexa-coordinate polynuclear Zn(II) and Cd(II) complexes derived from a single-armed salamo-based ligand

Abstract

A penta-coordinated dinuclear Zn(II) complex, [Zn₂(L)(μ-PhCOO)(EtOH)] (1), and a hexa-coordinate tetranuclear Cd(II) complex, [{Cd₂(L)(EtOH)(η-OAc)}₂]·2CH₂Cl₂ (2), have been synthesized by reactions of a single-armed salamo-based ligand, H₃L, and two kinds of transition metal salts, (Zn(NO₃)₂·6H₂O and Cd(OAc)₂·2H₂O), respectively. Complexes 1 and 2 have been characterized by elemental analyses, single crystal X-ray diffraction, IR spectra and UV-Vis spectra. Complex 1 is composed of a totally deprotonated ligand (L)^3- moiety, two Zn(II) ions, one μ-PhCOO^- counter-anion and one coordinated ethanol molecule. The (L)^3- unit packages two Zn(II) ions, the μ-PhCOO^- counter-anion bridges two adjacent Zn(II) ions and one ethanol molecule coordinates with the Zn2 ion, so that both Zn(II) ions are penta-coordinated with slightly distorted trigonal bipyramidal configurations, and the τ₅ values of Zn1 and Zn2 are 0.86 and 0.65, respectively. Complex 2 consists of two discrete and similar electroneutral tetra-nuclear units, 2 A and 2B, and two crystallized dichloromethane molecules. Each unit has a symmetric structure that is made up of two completely deprotonated ligand (L)^3- moieties, four Cd(II) ions, two η-OAc^- counter-anions and two coordinated ethanol molecules. Fluorescence properties and Hirshfeld surfaces analyses have been studied as well.

Keywords:

• Single-armed salamo-based ligand
• crystal structure
• Hirshfeld surface analysis
• fluorescence property

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Science and Technology Program of Gansu Province (21YF5GA057) and the National Natural Science Foundation of China (21761018), two of which are gratefully acknowledged.