Isolated molybdenum-based microporous POMs for selective adsorption of gases

Abstract

Dodecanuclear, icosanuclear and octanuclear porous MOF-like POMs materials [MoV12O12(μ2-O)4(μ3-O)12(Htrz)4(trz)4]∙nH2O (n = 22, 1; n = 92, 2; Htrz = 1H-1,2,3-triazole), [MoV8O8(μ2-O)12(Htrz)8]½∙[MoV12O12(μ2-O)4(μ3-O)12(Htrz)4(trz)4]∙44H2O (3), and [MoV8O8(μ2-O)12(Htrz)8]·62H2O (4) have been obtained and well...

Crown ether-like discrete clusters for sodium binding and gas adsorption

“…[35][36][37] We have reported porous materials directly constructed from isopolyoxomolybdates previously. 38,39 In this study, four hexanuclear dis- Interestingly, sodium cations are trapped inside and outside the holes as crown-ether-like complexes. 40 Deprotonated triazoles and embedded Na + keep the whole molecule neutral in 1-4.…”

“…These Mo 6 clusters obtained in homogeneous alkaline water solution have also been supported by our previous statistical results. 38,39 In addition, the ratios of molybdenum salts to Na 2 S 2 O 4 and 1,2,3-triazoles are crucial for the isolation of these oxidomolybdenum clusters. Na 2 S 2 O 4 is used in this system as a necessary additive responsible for reducing hexavalent molybdenum to the pentavalent state.…”

“…35–37 We have reported porous materials directly constructed from isopolyoxomolybdates previously. 38,39 In this study, four hexanuclear discrete clusters [Mo 6 O 6 (μ 2 -O) 9 (Htrz) 6 ]·15H 2 O ( 1 ), Na[Mo 6 O 6 (μ 2 -O) 9 (Htrz) 5 (trz)]·12H 2 O ( 2 ), Na 2 [Mo 6 O 6 (μ 2 -O) 9 (Htrz) 4 (trz) 2 ]·10H 2 O ( 3 ), and Na 2 [Mo 6 O 6 (μ 2 -O) 9 (Htrz) 4 (trz) 2 ]·49H 2 O ( 4 ) have been further constructed in alkaline solutions successfully. Interestingly, sodium cations are trapped inside and outside the holes as crown-ether-like complexes.…”

Successive constructions of regular tetra-, hexa- and octanuclear microporous polyoxovanadates(iii) for gas adsorption

“…Comparisons of the adsorbed CO 2 data for 1 , 2 and 4 with other porous polyoxometalates at 298 K are listed in Table S6 †. In comparison with 1 , 2 , [Mo V 8 O 8 (μ 2 -O) 12 (Htrz) 8 ]·62H 2 O 20 and Na 3 [Mo V 6 O 6 (μ 2 -O) 9 (Htrz) 3 (trz) 3 ]·7.5H 2 O, 19 4 exhibits good selective adsorption for CO 2 . Even so, we can see that the adsorption ability of 4 is minuscule when compared with those of other porous polyoxometalates like COMOC-2, 57 SO 2 -COMOC-2, 57 MFM-300(V III ), 32 MFM-300(V IV ), 32 NH 2 -MIL-47, 58 and V-MIL-100, 59 which can be ascribed to the large pore sizes of the latter.…”

“…Self-assembly has proven to be a powerful method to obtain POM-based materials, and the resulted intrinsic self-assembled POMOFs would exhibit classic and novel performances. 19,20 Five-membered heterocycles such as pyrazole and triazole ligands exhibit strong properties as neutral bridging ligands between two or three transition metal centers due to the strong σ donor atoms in the five-membered ring. Thus, substitutions of partial or all bridging oxygen atoms and bridging hydroxy groups on POV skeletons with pyrazole and triazole ligands are feasible ways to achieve POV building units and the self-assembly of POMOFs.…”