Coordination polymers from 1,3,4‐thiadiazole‐2,5‐dithiol and metal ions

Abstract

The copolymerization of 1,3,4-thiadiazole-2,5-dithiol (bismuthiol) with 1+, 2+, and 3+ valent metals is reported. Polymerization conditions were mimicked by means of Job's technique of solutions mixing. The polymers in aqueous solution do not conduct electricity, but electrolytes are formed in proportion to polymer formation and the pH changes. The metal concentration in solutions confirms the metal-ligand stoichiometry. The UV absorption of the ligand (at 320 nm) decreases and light scattering by polymer (at 380 nm) increases with polymer formation. The stoichiometry of polymers (obtained from the conductivity inflection point and metal analysis) is as follows, Mt2+: bismuthiolate = 1 : 1; A13+ : bismuthiolate = 2 : 3 and Ag+ : bismuthiolate = 2 : 1. Equations describing polymer formation on the basis of the solution conductivities are presented, and a model of polymer formation is proposed. It is concluded that 2+ valent metals form linear polymers but A13+ forms branched polymers.

Visible‐Light‐Active Mixed‐Valent Copper‐Ion‐Coordinated 2,5‐Dimercapto‐1,3,4‐thiadiazole‐Based p‐Type Metallopolymer

“…However, it is known that the ring sulfur remains out of coordination with metal centers. [9,10] The FTIR spectral analysis of the metal ions containing polymers shows a spectral features from that of monomer (K 2 DMcT) ( Figure S2.) Upon coordination with the metal centers there is a significant shift in the band positions of CÀ S, CÀ N, C=N.…”

“…The excellent coordination capability of 2,5-dimercapto-1,3,4-thiadiazole (DMcT) with transition metal ions are known to readily form metallopolymeric network through the linkage with the exocyclic thio units and endocyclic nitrogen atoms. [9][10][11] Electrochemical properties of DMcT and poly-DMcT have been previously well documented. [12][13][14] In our present work, the copper ions containing metallopolymers were prepared by controlled addition of 0.1 M CuSO 4 to 20 ml of 0.2 M 2,5dimercapto-1,3,4-Thiadiazole dipotassium salt solution (K 2 DMcT) under continuous stirring for 10 minutes.…”

“…The polymerization of K 2 DMcT with divalent cations was found to form linear polymers, while trivalent cations forms branched polymeric structures. [9,10] The FTO electrodes were coated with polymeric copper ion containing metallopolymer (Poly-CuDMcT) with conductive Nafion binder and by potentiostatic electropolymerization method. During the electropolymerization, the metal ion to ligand concentration is very crucial to avoid the extended polymerization and precipitation inside the electrolytic bath.…”

“…[11,13,14] The thiadiazole ring nitrogen atoms are capable to coordinate with the metal centers in the polymeric network. [9][10][11] However, the absence of peaks at lower binding energy in the nitrogen XPS spectra suggests the absence of this coordination with copper ions. The thio units of DMcT act as the coordination sites and bridges the metal centers.…”

Synthesis and characterization of some novel ruthenium(II) complexes containing thiolate ligands

“…Tautomerization influences the reactivity of thiadiazoles and has been demonstrated in the polymerization processes [7], substitution reactions at different moieties [8,9], and in metal complexation reactions [5,6]. A variety of N-heterocyclic thiones having 5-membered, 6-membered and other condensed cycles have extensively been used in the synthesis of both transition and non-transition metal complexes [10][11][12][13]. Among these, 2-mercapto-5-methyl-1,3,5-thiadiazole (HL 1 ), 2-mercapto-4-methyl-5-thiazoleacetic acid (HL 2 ), and 2-mercaptobenzothiazole (HL 3 ) are particularly interesting.…”