Triazole-assisted trinuclear oxidovanadium(IV) complexes for gas adsorptions

Novel trinuclear oxidovanadium(IV) triazole-based complexes K2Na[V3O3(μ3-O)(ox)3(H-4-trz)2(4-trz)]·3H2O (ox = oxalate, H-4-trz = 1,2,4-triazole) and [V3O3(μ3-O)(H-3-trz)2(3-trz)4]·5H2O (H-3-trz = 1,2,3-triazole) have been obtained in alkaline solution. The former exists inner channels with diameter of 12 Å, which shows selective adsorption for biogases O2 and CO2. [Display omitted] •Two trinuclear oxidovanadium(IV) complexes with triazole bridges were isolated in alkaline solution.•Interestingly, 1 and 2 exist 1 D channels with diameters of 12 Å and 6 Å respectively.•Compound 1 can selectively adsorb oxygen and carbon dioxide. Two novel microporous trinuclear oxidovanadium(IV) triazole frameworks, K2Na[V3O3(μ3-O)(ox)3(H-4-trz)2(4-trz)]·3H2O (1) and [V3O3(μ3-O)(H-3-trz)2(3-trz)4]·5H2O (2) (ox = oxalate, H-4-trz = 1H-1,2,4-triazole, H-3-trz = 1-H-1,2,3-triazole) have been obtained from alkaline solution respectively. Three vanadium atoms are closely connected together by deprotonated/protonated triazole ligands and bridging oxygen, leading to an equilateral triangular structure. Both 1 and 2 were well characterized by X-ray structural analyses, IR and UV–vis spectra, power XRD patterns, theoretical bond valence calculations (BVS) and EPR spectra. Moreover, 1 exists an inner channel diameter of 12.0 Å, showing selective O2 and CO2 adsorption of 23.91 and 14.22 mg/g under 29.9 bar respectively, which has potential application in O2/N2 and CO2/H2 separation.