The Design, Synthesis And Properties Of Bithiazole-Containing Polymers And Their Complexes

Polymer complexes with magnetic properties have received considerable interest due to their potential applications in a wide range of areas. The magnetism between the metal ions can be controlled by varying the size of the constitutional repeating units of the polymer, or by using different types of metal ions. This approach allows one to find polymeric ferromagnetic materials with high Tc.The paper report the design and synthesis of novel bithiazole-containing polymers and their complexes with transition metal ions or rare-earth metal ions as well as the magnetic properties of the complexes. The aim is to look for new ferromagnetic materials and to have a preliminary study on the relations between the magnetism and the polymer structures or the different kinds of metals.Two novel fully conjugated polymers containing bithiazole rings (PDDBTz and PDABTz) were first synthesized by polycondensation of 2,7-dimethyl-2,4,6-Octa-triene-1,8-dial with 2,2'-Bis(diethylphosphinatymethyl)-4,4'-bithizole or 2,2'-diamino-4,4'-bithiazole (DABT). And four novel copolymers containing bithiazole rings and ethylene oxide on the skeleton (PPDOBT, PPTOBT, PNDOBT and PNTOBT) were prepared via Schiff reaction and Ullmann reaction. And three other novel conjugated polymers containing bithiazylenevinylene (PBTzV, PPVBTz and PPHBTz) were also obtained by the method reported by Gilch and the Wittig-Horner reaction. And some polymer complexes with Pr³⁺, Sm³⁺, Ni²⁺ and Cu²⁺ were also obtained. The structures of these products were determined by FT-IR, ¹H NMR and elemental analysis. The metal contents of the complexes were measured by complexometric titration.The spectroscopy properties of the polymers PBTzV, PPVBTz and PPHBTz werestudied by UV-Vis absorption and photoluminescence (PL) spectra. Inserting the phenylene segment with n-decyloxy pendant chains into the bithiazylenevinylene main chain to form PPHBTz results a good improvement in solubility. And the emissive region was shifted from blue to green. The protonation of bithiazole rings was first investigated with an increasing addition of TFA to 5.0x10³M, which show a red shift about 15nm of PPHBTz.The magnetic behavior of PDDBTz-Pr3+, PDDBTz-Sm3+ and PDABTz-Pr3+ were measured as a function of magnetic field strength (0-60kOe) at 4 K and as a function of temperature (4-300 K) at magnetic field strength of 30kOe.. It can be concluded from the magnetic data that PDDBTz-Pr3+, PDABTz-Pr3+ and PDDBTz-Sm3+ are soft ferromagnet. And the magnetic properties of PPTOBT-Cu2+, PPTOBT-Ni2+, PNTOBT-Cu2+ and PNTOBT-Ni2+ were also studied. The results show that they all exhibit features of soft ferromagnet. PPTOBT-Ni2+ and PNTOBT-Ni2+ follow the Curie-Weiss relationship, %=C/(T-8), in the range of 250-300K, with the same Curie-Weiss temperature 0=160K. PPTOBT-Cu2+ and PNTOBT-Cu2+don't follow the traditional ferromagnet. They have a transmit temperature. They exhibit features of ferromagnet as the temperature is higher than it and exhibit features of antimagnet as the temperature is lower than it.