title: Single-atom ligand changes affect breathing in an extended metal-organic framework.
abstract: 2-Phenylpyridine-5,4'-dicarboxylic acid (1, dcppy), a derivative of 4,4'-biphenyldicarboxylic (2, bpdc) was used as the organic linking component for several metal-organic frameworks (MOFs). The pyridine component of 1 does not interfere with the solvothermal synthetic procedure, and hence both 1 and 2 form similar isoreticular MOFs. Zr(4+)-based UiO-67-dcppy, Al(3+)-based DUT-5-dcppy, Zn(2+)-based DMOF-1-dcppy, and interpenetrated Zn(2+)-based BMOF-1-dcppy were readily synthesized from 1. Similarly, isostructural frameworks from 2 were prepared (UiO-67, DUT-5, DMOF-1-bpdc, and interpenetrated BMOF-1-bpdc). The structures and physical properties of these frameworks were characterized by powder X-ray diffraction (PXRD), single X-ray diffraction (XRD), thermogravimetric analysis (TGA), and gas sorption analysis. Generally, frameworks prepared from 1 or 2 displayed similar properties; however, gas sorption data showed that BMOF-1-dcppy displayed a very large hysteresis with N(2) and CO(2) suggestive of possible framework flexibility. In contrast, the analogous framework prepared from 2 (BMOF-1-bpdc) showed low uptake of N(2) and CO(2). The substantial difference in the gas sorption behavior of these MOFs is attributed to the pyridine nature of 1 that results in weakened π-π interactions between the interpenetrated nets.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA.
authors.forename: Phuong V
authors.initials: PV
authors.lastname: Dau
authors.forename: Min
authors.initials: M
authors.lastname: Kim
authors.forename: Sergio J
authors.initials: SJ
authors.lastname: Garibay
authors.forename: Frédéric H L
authors.initials: FH
authors.lastname: Münch
authors.forename: Curtis E
authors.initials: CE
authors.lastname: Moore
authors.forename: Seth M
authors.initials: SM
authors.lastname: Cohen