PDF《sorption behaviours》

260 °C to form the small-pore (sp) phase [Cu4(btm)2] (denoted as MAF-42-sp or simpli?ed as MAF-42), which can be stable up to

410 °C (Supplementary Figs

3 and 4). Single-crystal structure of MAF- 42-sp (Supplementary Table 1) showed signi?cantly contracted unit cell (C22%) and channel size (void 14.1%, cross-section size 2.4 ? 2.6C3.5? 3.7?2) because the cross angle of packed ribbons reduced from 72° to 53° (Fig. 2b)5,8. In MAF-42-sp, the Cu(I) ions and methylene groups are less exposed on the pore surface;

however, their separations are similar to those in MAF-42-lp (Supplementary Table 2). While the coordination bond lengths were changed very little (Dmax ? 0.022?), the structural variation mainly occurred on the ligand conformations and coordination N N N N N N CuI CuI CuI CuI N N N O2 N N N N N N CuI CuII CuI N N N O O H2O N N N N N N CuI CuI CuI N N N O Figure

1 | Bioinspired aerobic oxidation strategy for multifunctional porous frameworks. (a) The O2-activating site in a typical copper protein. (b) The possible coordination structure and reactivity of an extended network solid (porous crystal) consisting of Cu(I) and a methylene-bridged bistriazolate ligand. ARTICLE NATURE COMMUNICATIONS | DOI: 10.1038/ncomms7350

2 NATURE COMMUNICATIONS | 6:6350 | DOI: 10.1038/ncomms7350 | www.nature.com/naturecommunications &

2015 Macmillan Publishers Limited. All rights reserved. geometries of the Cu(I) ions serving as the joints between the ribbon-like fragments (Dmax ? 7.3°;

Supplementary Tables

2 and 3). Actually, the ligand-bending directions are reversed, that is, the average torsion angle between two triazolate rings of btm2? changes from 167.6° in MAF-42-lp to ? 165.1° in MAF- 42-sp (Supplementary Fig. 5). The structure transformation between C6H6@MAF-42-lp and MAF-42-sp can be reversibly triggered by adsorption/desorption of benzene vapour (Supplementary Fig. 4). Self-catalysed aerobic oxidation. In air, colourless C6H6@MAF- 42-lp turns brown and then black quickly (Fig. 3a), which should not be originated from Cu(I) to Cu(II) oxidation because the Cu(II) complex is usually blue or green. Electrospray ionization mass spectrometry of the demetalated samples showed that fresh C6H6@MAF-42-lp has only a signal at m/z ?

179 (H3btm? ), while a new peak at m/z ?

193 corresponding to the expected oxidation product bis(5-methyl-1,2,4-triazol-3-yl)methanone (H3btk? ) appeared after the sample was exposed in air (Supplementary Fig. 6). The infrared spectrum of the oxidized sample exhibits a strong band at

1641 cm?

1 in the characteristic region of 1,750±150 cm?

1 for carbonyl groups (Supplementary Fig. 7). The single-crystal structure of a black crystal obtained by prolonged exposure (1 month) of C6H6@MAF-42-lp in air was measured (Supplementary Table 1). A residual electron peak appeared near one of the two crystallographically independent methylene groups that adjacent to the two-coordinated Cu(I) ion, which can be re?ned as an oxygen atom without any restriction, giving an occupancy of 0.28(5) and a C ? O bond length of 1.20(5) ? (Supplementary Fig. 8)33. These observations demonstrated that the btm2 ? ligands in C6H6@MAF-42-lp can be readily oxidized by air at room temperature, although the reaction rate is quite slow. The oxidation of MAF-42-sp (almost no colour change after exposed in air at room temperature for several days) is much slower, which may be ascribed to the even smaller pore size and less exposed active sites. The TG analysis showed that heating microcrystalline MAF- 42-sp in an O2 ?ow at