Syntheses, Crystal Structures, and Catalytic Activities of Two Inorganic–Organic Hybrid Materials: [py]2[Hpy]3[PMo12O40]·H2O and [btx]2[Mo8O26]·H2O

Abstract

Two novel organic–inorganic hybrid supramolecular compounds based on organic cations and POMs, namely, [py]2[Hpy]3[PMo12O40]·H2O (1) and [btx]2[Mo8O26]·H2O (2) [btx = 1,6-bis(triethylmethylammonium)xylol], have been hydrothermally synthesized and characterized by single-crystal x-ray diffraction, infrared (IR) spectroscopy, and thermal gravimetric analysis (TGA). The compound 1 crystallizes in the monoclinic, space group P2(1)/c with a = 17.7932(18) Å, b = 19.427(2) Å, c = 15.2515(16) Å, β = 98.479(2)°. Compound 2 crystallizes in the triclinic, space group P-1 with a = 11.6245(8)Å, b = 11.9573(13)Å, c = 12.8756(10)Å, α = 63.830(6)°, β = 75.285(5)°, γ = 68.024(5)°. Compound 1 contained the classical Keggin-type discrete [PMo12O40]3− anion and 2 had the a-[Mo8O26]4− cluster. Moreover, it was indicated that these polyacid compounds had definite catalytic activities on the reaction of acetaldehyde oxidation to acetic acid.