Intrinsic Molybdenum‐Based POMOFs with Impressive Gas Adsorptions and Photochromism
Lan Deng, Xin Dong, Zhao‐Hui Zhou
Abstract
Abstract Novel molybdenum(VI/V) POM‐based self‐constructed frameworks [Mo VI 12 O 24 (μ 2 ‐O) 12 (trz) 6 (H 2 O) 6 ] ⋅ 6Hma ⋅ 18H 2 O ( 1 , Htrz=1 H ‐1,2,3‐triazole, ma=methylamine), [Mo VI 7 O 14 (μ 2 ‐O) 8 (trz) 5 (H 2 O)] ⋅ 7Hma ⋅ 5H 2 O ( 2 ), Na 3 [Mo V 6 O 6 (μ 2 ‐O) 9 (Htrz) 3 (trz) 3 ] ⋅ 7.5H 2 O ( 3 ) and [Mo V 8 O 8 (μ 2 ‐O) 12 (Htrz) 8 ] ⋅ 30H 2 O ( 4 ) have been covalently decorated with tri‐coordinated deprotonated/protonated 1,2,3‐triazoles. Channels with an inner diameter of 7.5 Å were found in 1 , whereas a tunnel composed of stacking molecules with an inner diameter of 4.1 Å along the b ‐axis exists in 2 ; it is occupied by free disordered methylamines, showing selective adsorption of O 2 and CO 2 at 25 °C. Obvious downfield shifts were observed by 13 C NMR spectroscopies for methylamines inside the confined channels in 1 and 2 . There are diversified pores in 3 and 4 , which are formed by the molecules themselves and intermolecular accumulations. Adsorption tests indicate that 3 and 4 are fine adsorption materials for CH 4 and CO 2 under low pressure that rely on the environments built by the POMs. Correspondingly, 1 and 2 display reversible photoresponsive thermochromism that is subtlety influenced by the channels. The polyoxometalate organic frameworks (POMOFs) with multiple functional adsorptions are easy to assemble. Their photo‐/thermoresponse properties offer a new pathway for the self‐constructions of one‐off hybrid materials that possess the good properties of both POMs and MOFs.