Organic - Inorganic Hybrid Materials Based On Organic Dyes And Polyoxometalates Synthesis And Properties

POM-based inorganic-organic hybrid materials have attracted increasing attention in recent years due to their unique structures and outstanding performances. Because of the optical, electro and magnetic properties, these inorganic-organic hybrid materials have widespread application in medical science, magnetism, catalysis, non-linear optical materials, conducting materials, photochromic and electrochromic materials. This paper reports eight novel inorganic-organic hybrid materials based on dyes and POMs, and all of them are isolated in crystalline state.hybrid materials based on methylene blue(MB) as the electron donor: [C22H18N3S]2Mo6O19·2DMF (1) [C22H18N3S]2W6O19·2DMF (2) [C16H18N3S]4Mo8O26·2DMF (3) [C16H18N3S]4PMo12O40·2DMF·H2O(5) [C16H18N3S]2[C16H18N3S2]2SiMo12O40 (6) [C16H18N3S]4W10O32·6DMF (7)hybrid materials based on new methylene blue(NMB) as the electron donor: [C18H22N3S]4Mo8O26·2DMF (4) [C18H22N3S]4W10O32·6DMF (8)The new compounds were characterized by IR, ESI-MS, solid diffuse reflectance spectrum, UV-Vis spectra in DMF solution, CV, Luminescent spectrum both in solid and liquid state. Single-crystal X-ray of the title compounds 1-8 revealed that their exit strong interactions between the electron donors and the polyanions, such as Coulombic force, C-H…O, N-H…O and C-H…S hydrogen bonds, or strong C-H…πandπ…πstacking among organic dyes. The solid diffuse reflectance spectra of compound 1-8 indicated the charge-transfer transition occurred between the cationic dye donor and the POM acceptors. UV-Vis spectra in DMF solution illustrated these compounds have intense absorption in both ultraviolet and visible regions. Studies of the photoluminescent properties showed that the formation of compound 1-8 lead to the fluorescence quenching and blueshift of emission peak of organic dyes due to the strong interaction between the donor cations and polyanions.