Synthesis and characterization of poly(1‐benzoylthiosemicarbazide) and poly(1,3,4‐thiadiazole amine) from 2‐(p‐aminophenyl)‐1,3,4‐oxadiazoline‐5‐thione via ring‐opening process

Abstract

A novel thermally stable and semiconducting polyheterocycle, poly(l,3,4-thiadiazole amine), was synthesized from 2-(p-aminophenyl)-l,3,4-oxadiazoline-5-thione via ring-opening. The polymer is a new class of ordered alternating copoly(ani1ine) containing 1,3,4-thiadiazole heterocyclic units. An investigation of the reaction of 2-phenyl-l,3,4-oxadiazoline-5-thione with aniline was conducted as a model reaction for the polymerization, and poly(phosphoric acid) (PPA) and phosphorus pentoxide/methanesulfonic acid (PPMA) were found to be favorable both as condensing agent and solvent for the formation of 2-anilino-5-phenyl-l,3,4-thiadiazole as a model compound. The polymerization was carried out both by two-step procedure that included ring-opening self-polyaddition giving poly(1-benzoylthiosemicarbazide), followed by cyclodehydration to poly(l,3,4-thiadiazole amine), and by a one-step procedure including cyclodehydration in situ. The poly(1 -benzoylthiosemicarbazide) which was formed in the first step in m-cresol had reduced viscosities up to 0,42 dL . g-', and it was converted to poly(l,3,4-thiadiazole amine) by treating in PPA or PPMA. Poly(l,3,4-thiadiazole amine) having reduced viscosities up to 0,25 dL . g was also synthesized by the direct one-step polymerization in PPA or PPMA.The polymer is highly thermally stable and exhibited no weight loss up to 350 "C under nitrogen.Its electric conductivity was less than lo-'' S * cm-' at ambient temperature, but markedly increased to 2,9. lo-' S . cm-' upon doping with iodine.

Synthesis and Characterization of Some New Heteroaromatic Compounds Having Chirality Adjacent to a 1,3,4‐Thiadiazole Moiety and Their Antimicrobial Activities

“…1,3,4‐Thiadiazole compounds are one of the most interesting five‐membered heteroaromatic compounds . Moreover, 1,3,4‐thiadiazoles, as an important type of heterocyclic compounds, have attracted research interest as intermediates for the synthesis of medicinal , pesticidal , and polymer agents and for chemical synthesis . Since the discovery of 1,3,4‐thiadiazoles in 1882, many derivatives have been synthesized, and a great deal of attention has been focused on their applications, including as medicinal, pharmaceutical, and agrochemical .…”

DC electrical conductivity of polyazomethinethiosemicarbazone metal complexes

“…Indeed, plastics have been extensively utilized by the electronics industry for this property. Since the discovery of organic conducting polymers, intensive research has been made with the aim of designing polymers with good conducting properties1, 2 Doping polyazomethines with iodine have been reported to raise the electrical conductivity which is originally in the order 10 −12 −10 −10 S cm −1 to 10 −7 −10 −4 S cm −1 3–5…”