Study On Preparation Of Self-assembled Multilayer Films Containing Bithiazole Rings And The Magnetic Properties Of Their Metal Complexes

Organic magnetism is a rapidly developing field that combines the skills of experimental and theoretical scientists in many areas of chemistry and physics. Compared with inorganic ferromagnet, the organic ferromagnet exhibits the characteristics of structural diversities, low density, and readily processing. In addition, layer-by-layer (LBL) assembled multilayered films have received considerable interest because they allow fabrication of supramolecules with tailored architecture and properties. The development and status of organic magnetic materials and self-assembled films have been summarized in this paper. The main task has been proposed on the basis of the introduction, which including the preparation of self- assembled multilayered films and its complexes, the relationship of their structures and magnetic properties. The aim of these studies is supposed to contribute to the theoretical research of organic magnetic materials.4,4'-(4,4'-bithiazole-2,2'-diylbis(diazene-2,1-diyl))diphenol(BTDP) was first synthesized from phenol and 2,2'-diamino-4,4'-bithiazole(DABT) in this aticle, and characterized by FTIR and ¹H NMR. The self-assemble of BTDP with poly(diallydimethylammonium chloride) (PDDA) was carried out on the quartz glass and PE film. The multilayer buildup was monitored by UV- Visible spectroscopy. The linear increased of the absorbance with increasing the number of bilayers indicates a process of uniform assembling. The complexes (PE-(PDDA/BTDP-M²⁺)_n) were prepared with Ni²⁺ and Cu²⁺ and characterized by FTIR and UV-Visible which showed that the chelation of transition metal ions had taken place.The BTDP and PDDA deposit which prepared by mixing their solution reacted with metal ions Ni²⁺, Cu²⁺, Fe²⁺, Nd₃₊ to produce 4 novel polymer-metal complexes. FTIR were applied to characterize their structure and the metal content was determined by complexometric titration.The magnetic properties of 5 of these polymer-metal complexes were measured by a PPMS-9T magnetometer (QUANTUM DESIGN), which include magnetization versus temperature, magnetization versus applied field, magnetic susceptibility versus temperature and magnetic hysteresis. The temperature is ranged from 4 to 300 K and the intensity of magnetic field is ranged from -50 to 50 kOe. According to the measurement it can be concluded that PE-(PDDA/BTDP-Ni²⁺)_n, PE-(PDDA/BTDP-Cu²⁺)_n were soft ferromagnet; deposit complexes PDDA/BTDP-Ni²⁺, PDDA/BTDP-Cu²⁺, PDDA/BTDP-Fe²⁺ antiferromagnet; deposit complexes PDDA/BTDP-Nd³⁺ exhibited a special magnetic property: along with the decreasing of temperature, they changes from a diamagnet to ferromagnet with a certain transition temperature.The comparation of self-assembled multilayered films and deposit complexes were carried out. It showed that the magnetic properties of self-assembled films (PE-(PDDA/BTDP-M²⁺)_n) were much better than that of deposit complexes (PDDA/BTDP-M²⁺). This phenomenon might be caused by the good order of the self- assembled multilayered films.