| Autor: |
Xiao, DJ, Gonzalez, MI, Darago, LE, Vogiatzis, KD, Haldoupis, E, Gagliardi, L, Long, JR |
| Jazyk: |
angličtina |
| Rok vydání: |
2016 |
| Zdroj: |
Xiao, DJ; Gonzalez, MI; Darago, LE; Vogiatzis, KD; Haldoupis, E; Gagliardi, L; et al.(2016). Selective, Tunable O2Binding in Cobalt(II)-Triazolate/Pyrazolate Metal-Organic Frameworks. Journal of the American Chemical Society, 138(22), 7161-7170. doi: 10.1021/jacs.6b03680. UC Berkeley: Retrieved from: http://www.escholarship.org/uc/item/2h27v960 |
| DOI: |
10.1021/jacs.6b03680. |
| Popis: |
© 2016 American Chemical Society. The air-free reaction of CoCl2with 1,3,5-tri(1H-1,2,3-triazol-5-yl)benzene (H3BTTri) in N,N-dimethylformamide (DMF) and methanol leads to the formation of Co-BTTri (Co3[(Co4Cl)3(BTTri)8]2·DMF), a sodalite-type metal-organic framework. Desolvation of this material generates coordinatively unsaturated low-spin cobalt(II) centers that exhibit a strong preference for binding O2over N2, with isosteric heats of adsorption (Qst) of -34(1) and -12(1) kJ/mol, respectively. The low-spin (S = 1/2) electronic configuration of the metal centers in the desolvated framework is supported by structural, magnetic susceptibility, and computational studies. A single-crystal X-ray structure determination reveals that O2binds end-on to each framework cobalt center in a 1:1 ratio with a Co-O2bond distance of 1.973(6) Å. Replacement of one of the triazolate linkers with a more electron-donating pyrazolate group leads to the isostructural framework Co-BDTriP (Co3[(Co4Cl)3(BDTriP)8]2·DMF; H3BDTriP = 5,5′-(5-(1H-pyrazol-4-yl)-1,3-phenylene)bis(1H-1,2,3-triazole)), which demonstrates markedly higher yet still fully reversible O2affinities (Qst= -47(1) kJ/mol at low loadings). Electronic structure calculations suggest that the O2adducts in Co-BTTri are best described as cobalt(II)-dioxygen species with partial electron transfer, while the stronger binding sites in Co-BDTriP form cobalt(III)-superoxo moieties. The stability, selectivity, and high O2adsorption capacity of these materials render them promising new adsorbents for air separation processes. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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