Synthesis, crystal structure, and electrochemical properties of Cu(I) coordination polymers with two new (NS)₂ Schiff-base ligands containing long flexible spacers

Abstract

Two new (NS)₂ Schiff bases, (4-NO₂Ph)₂dapte (N,N′-di-(4-nitrobenzaldimine)-1,2-di(o-aminophenylthio)ethane) (1) and (thio)₂daptx (N,N′-di-(thiophenedimine)-1,4-di(o-aminophenylthio)xylene) (2), and their 1-D copper(I) coordination polymers [Cu₂(μ-Br)₂(μ-(4-NO₂Ph)₂dapte)] _n (3), [Cu₂(μ-I)₂(μ-(4-NO₂Ph)₂dapte)] _n (4), and [Cu₂(μ-I)₂(μ-(thio)₂daptx)] _n (5) have been synthesized and characterized by elemental analyses and IR, UV-Vis, and ¹H NMR spectroscopy. The structures of 4 and 5 have been determined by X-ray crystallography and were shown to consist of Cu₂(μ-I)₂ secondary building units (SBUs) bridged by (4-NO₂Ph)₂dapte or (thio)₂daptx ligands. The CuNSI₂ coordination sphere is a distorted tetrahedral in both cases. Both (4-NO₂Ph)₂dapte and (thio)₂daptx are N₂S₂-bis-bidentate chelating ligands with the two imine nitrogens and two thioether sulfurs in a trans configuration generating dinuclear [Cu₂(μ-(4-NO₂Ph)₂dapte)] and [Cu₂(μ-(thio)₂daptx)]. These units are connected by two bridging iodides to form 1-D copper(I) coordination polymers. The electrochemical properties of 3–5 are also reported and discussed.

Keywords:

• Bis-bidentate Schiff base
• Copper(I) halide aggregate
• One-dimensional coordination polymer
• X-ray diffraction
• Cyclic voltammetry

Acknowledgment

Partial support of this work by the Isfahan University of Technology Research Council is gratefully acknowledged.