Structural diversity in schiff base complexes of Ga(III), In(III), Pb(II), and Zn(II): Precursors and model systems for conducting metallopolymers

Abstract

A variety of Schiff base ligands have been synthesized in an effort to study the coordination chemistry of these ligands when reacted with various metal salts. By varying the structural features of the ligand as well as the synthetic route used to make the corresponding metal complexes, a number of different structural motifs have been observed. Schiff base ligands were chosen due to their ease of synthesis as well as their ability to bind a variety of metal salts. These complexes serve as model systems for and precursors to monomers for the preparation of conducting metallopolymers. Further functionalization of the Schiff base ligand with bithiophene end groups has resulted in electropolymerizable monomers. When polymerized these monomers give conducting metallopolymers which can then be used for a variety of applications. The products were characterized by multinuclear NMR, UV-Vis, and IR spectroscopy, and mass spectrometry. Solid-state structures were determined by single crystal X-ray diffraction studies. Electropolymerization yielded novel conducting polymers with embedded metals.

(E)-4-[7-(2,3-Dihydrothieno[3,4-b][1,4]dioxin-5-yl)-2,1,3-benzothiadiazol-4-yl]-2-[(neopentylimino)methyl]phenol

“…The dihedral angle between the benzothiadiazole moeity and the thiophene ring is 23.43 (9)° and the dihedral angle between the benzothiadiazole moeity and the phenol ring is 35.45 (9)°. The geometry of the ethylenedioxythiophene moiety is similar to other ethylenedioxythiophene containing compounds reported in the literature (Mejía et al, 2010;Wong et al, 2008)…”

“…For related structures, see: Mejía et al (2010); Wong et al (2008). For the properties of 3,4-ethylenedioxythiophene and benzothiadiazole compounds, see: Sendur et al (2010); Tanriverdi et al (2012); Holliday et al (2006); Ellinger et al (2011).…”

Side‐Chain Metallopolymers Containing Second‐Order NLO‐Active Bimetallic NiII and PdII Schiff‐Base Complexes: Syntheses, Structures, Electrochemical and Computational Studies

“…Polymeric materials that exhibit second‐order nonlinear optical (NLO) properties have attracted a great deal of attention due to their mechanical, thermal and electronic properties, as well as for their potential applications in new photonic technologies In this regard, the development of oligomers and polymers with new chemical structures for NLO materials continues to be an attractive area of research , . Metallopolymeric materials have included a variety of ligand systems for binding a metal center directly into the polymer backbone as well as using substituents to yield polymers with a pendant metal complex . One way of obtaining these latter materials is to covalently bind a NLO‐active chromophore to an organic polymer .…”

Understanding the Effect of Metal Centers on Charge Transport and Delocalization in Conducting Metallopolymers

“…The two outer Co­(II) ions have distorted octahedral coordination geometries with the salpen ligand occupying the four base coordination sites, one oxygen atom from a bridging acetate ligand occupying one apical site, and one oxygen atom from a bound DMF solvent molecule occupying the final coordination site. In our experience, this is a common structural motif in complexes of this type when they are synthesized from metal ions that prefer five- or six-coordinate geometries and from acetate metal salts. , For ZnL I two crystal structuresone monomeric and one dimeric trinuclearwere obtained under the same conditions (Figure )­. In the ZnL I mononuclear structure, the apical coordination site is occupied by a water molecule, and the coordination geometry of the Zn­(II) ion in this complex is distorted square pyramidal, defined by two N atoms and two O atoms of the Schiff-base ligand as the basal plane and by an apical O atom of the water molecule.…”