Title: Rational Design of Pore Size and Functionality in a Series of Isoreticular Zwitterionic Metal–Organic Frameworks

Abstract

The isoreticular expansion and functionalization of charged-polarized porosity has been systematically explored by the rational design of 11 isostructural zwitterionic metal-organic frameworks (ZW-MOFs). This extended series of general structural composition {[M₃F(L1)₃(L2)_1.5]·guests}_n was prepared by employing the solvothermal reaction of Co and Ni tetrafluoroborates with a binary ligand system composed of zwitterionic pyridinium derivatives and traditional functionalized ditopic carboxylate auxiliary ligands (HL1·Cl = 1-(4-carboxyphenyl)-4,4'-bipyridinium chloride, Hcpb·Cl; or 1-(4-carboxyphenyl-3-hydroxyphenyl)-4,4'-bipyridinium chloride, Hchpb·Cl; and H₂L2 = benzene-1,4-dicarboxylic acid, H₂bdc; 2-aminobenzene-1,4-dicarboxylic acid, H₂abdc; 2,5-dihydroxy-1,4-benzenedicarboxylic acid, H₂dhbdc; biphenyl-4,4'-dicarboxylic acid, H₂bpdc; or stilbene-4,4'-dicarboxylic acid, H₂sdc). Single-crystal structure analyses revealed cubic crystal symmetry (I-43m, a = 31-36 Å) with a 3D pore system of significant void space (73-81%). The pore system features three types of pores being systematically tunable in size ranging from 17.4 to 18.8 Å (pore I), 8.2 to 12.8 Å (pore II), and 4.8 to 10.4 Å (pore III) by the choice of auxiliary ligands. All members of this series have noninterpenetrating structures and exhibit robust architectures, as evidenced by their permanent porosity and high thermal stability (up to 300 °C). The structural integrity and specific surface areas could be systematically optimized using supercritical CO₂ exchange methods for framework activation resulting in BET surface areasmore » ranging from 1250 to 2250 m²/g. Most interestingly, as a structural landmark, we found the pore surfaces lined with charge gradients employed by the pyridinium ligands. This key feature results in significant adsorption of carbon dioxide and methane which is attributed to polarization effects. With this contribution we pioneer the reticulation of pyridinium building blocks into extended zwitterionic networks in which specific properties can be targeted.« less

Authors:

Aulakh, Darpandeep ^[1]; Islamoglu, Timur  ^[2];

• Search DOE PAGES for author "Islamoglu, Timur"
• Search DOE PAGES for ORCID "0000-0003-3688-9158"

Bagundes, Veronica F. ^[1]; Varghese, Juby R. ^[1]; Duell, Kyle ^[1]; Joy, Monu  ^[1];

• Search DOE PAGES for author "Joy, Monu"
• Search DOE PAGES for ORCID "0000-0003-1947-9691"

Teat, Simon J. ^[3]; Farha, Omar K.  ^[4];

• Search DOE PAGES for author "Farha, Omar K."
• Search DOE PAGES for ORCID "0000-0002-9904-9845"

Wriedt, Mario  ^[1]

• Search DOE PAGES for author "Wriedt, Mario"
• Search DOE PAGES for ORCID "0000-0003-3118-9507"

---

+ Show Author Affiliations

1. Clarkson Univ., Potsdam, NY (United States)
2. Northwestern Univ., Evanston, IL (United States)
3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
4. Northwestern Univ., Evanston, IL (United States); King Abdulaziz Univ., Jeddah (Saudi Arabia)

Publication Date:

Thu Oct 25 00:00:00 EDT 2018

Research Org.:

Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1581598

Grant/Contract Number:  

AC02-05CH11231; AC02-06CH11357

Resource Type:

Accepted Manuscript

Journal Name:

Chemistry of Materials

Additional Journal Information:

Journal Volume: 30; Journal Issue: 22; Journal ID: ISSN 0897-4756

Publisher:

American Chemical Society (ACS)

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE