Coordination Chemistry Reviews 426 (2021) 213542 Contents lists available at ScienceDirect Coordination Chemistry Reviews journal homepage: www.elsevier.com/locate/ccr Review Metal–organic frameworks based on multicarboxylate linkers Hosein Ghasempour a, Kun-Yu Wang b, Joshua A. Powell b, Farnoosh ZareKarizi a, ⇑ ⇑ Xiu-Liang Lv b, Ali Morsali a, , Hong-Cai Zhou b,c, a Department of Chemistry, Faculty of Sciences, Tarbiat Modares University, P.O. Box 14155-4838, Tehran, Iran b Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255, United States c Department of Materials Science and Engineering, Texas A&M University, College Station, Texas 77843-3003, United States article info abstract Article history: When designing metal–organic frameworks (MOFs), linker design is one of the most important factors in Received 8 July 2020 constructing a wide variety of structures. Judicious choice of linker size, geometry, and connectivity can Accepted 5 August 2020 create diverse structures and topologies, which can aid in the quest to design MOFs with both high sta- Available online 29 August 2020 bility and permanent porosity. Multi-connected linkers have become a focus in the MOF community, as high connectivity can improve stability and tunability of frameworks. In particular, multicarboxylate ligands have been reported extensively in the literature to construct stable MOFs with versatile pore environments, which can be termed as metal-multicarboxylate frameworks (MMCFs). These structures have great application potential in gas adsorption and separation, catalysis, and sensing. Herein, we review the literature on multicarboxylate linkers (nCOOH 3) in MOF systems and their applications, with specific emphasis on how high linker connectivity affects properties of MOFs such as topology, porosity, stability, and functionality. Ó 2020 Elsevier B.V. All rights reserved. Contents 1. Introduction . ........................................................................................................ 2 2. Topological and structural properties of MMCFs . .................................................................. 2 3. Porosity in MMCFs . ..................................................................................... 8 4. Stability in MMCFs . .................................................................................... 15 5. Flexibility in MMCFs . .................................................................................... 16 6. Mixed linker MMCFs . .................................................................................... 17 7. Synthetic methods in MMCFs . .................................................................................... 18 8. Functionality in MMCFs . .................................................................................... 19 9. Applications of MMCFs . .................................................................................... 21 9.1. Gas storage and separations . .......................................................................... 21 9.2. Catalysis . .......................................................................................... 22 9.3. Sensing. .......................................................................................... 23 9.4. Water adsorption . .......................................................................................... 23 9.5. Biological applications . .......................................................................................... 23 9.6. Other features of MMCFs .......................................................................................... 24 10. Conclusion and perspective. .................................................................................... 25 Declaration of Competing Interest . .................................................................................... 25 Acknowledgment . .................................................................................... 25 Appendix A. Supplementary data . .................................................................................... 25 References . ....................................................................................................... 25 ⇑ Corresponding authors at: Department of Chemistry, Faculty of Sciences, Tarbiat Modares University, P.O. Box 14155-4838, Tehran, Iran (A. Morsali); Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255, United States (H.-C. Zhou). E-mail addresses: [email protected] (A. Morsali), [email protected] (H.-C. Zhou). https://doi.org/10.1016/j.ccr.2020.213542 0010-8545/Ó 2020 Elsevier B.V. All rights reserved. 2 H. Ghasempour et al. / Coordination Chemistry Reviews 426 (2021) 213542 1. Introduction are other advantages of MOFs containing multicarboxylate linkers. Unfortunately, the complex and unpredictable structures of While coordination polymers composed of metal nodes and MMCFs can impede further study. organic linkers were firstly studied in the mid-20th century, the In addition to providing a general summary of reported MMCFs first permanently porous coordination polymer, commonly known (Schemes 1–6, Tables 1–6), this context aims to investigate the as a MOF, was not reported until the 1990s [1–8]. Upon the discov- structural consequences of multicarboxylate linkers in MOFs, such ery of MOFs, these materials became the center of attention for as their influence on topology, porosity, stability, flexibility and the researchers across diverse fields [9–11]. Their high porosity, effectiveness of the MOFs in a range of applications. extreme versatility and structural tunability provide multiple advantages over other porous materials like activated carbons or zeolites for diverse applications such as catalysis [12–18], gas stor- 2. Topological and structural properties of MMCFs age and separation [19–21], energy applications [22,23] and sequestration of toxic chemicals [24,25]. One of the earliest MOF Knowledge, prediction, and classification of network topology was published in 1999, with the framework comprised of zinc are important for designing novel MOFs with specific characteris- acetate (Zn4O(COO)6) clusters and the well-known ditopic linker tics and, as such, topological exploration in MOFs has become an benzene dicarboxylate (BDC2À) [26]. Further studies elaborated important focus of MOF chemists in recent years [53–55]. Design- on this design to form a series of isoreticular MOFs (IRMOFs) by ing the network topology in MOFs can be done within two main substituting BDC2À with other ditopic linkers in a process known routes, changing the cluster connectivity or altering the linker’s as reticular synthesis [27]. Despite the potential of these materials, topological geometry. Metal clusters adopt established geometries the susceptibility of the zinc acetate cluster to hydrolysis limits which cannot be easily modified to change connectivity. Therefore, their applicability in gas adsorption and separation, as these logical designing of linker geometry is essential for discovering processes often take place in humid environments [28,29]. This specified topologies as an ideal platform for designing MOFs. drawback inspired design of MOFs containing binuclear Choosing linkers with flexible branches, desired dihedral angles, M2-paddlewheel clusters (M = Zn or Cu), which show improved and topological shapes are among the advantages of using multi- water stability. Although the assembly of these clusters with carboxylate linkers. One exciting study was the discovery of the H2BDC-type ditopic linkers always leads to a 2D layered coordina- gea net as an ideal blueprint net by Guillerm et al. Their geometri- tion polymer instead of a 3D framework, the combination of a cal analysis of the gea-a net revealed that transposition of pre- tricarboxylate linker, benzene tricarboxylate (BTC3À), and a copper known copper paddlewheels eto MOP [56] into the anticipated paddlewheel cluster led to the highly porous and stable 3D frame- gea-MOF platform required the employment of a multicarboxylate ° work HKUST-1 ([Cu3(BTC)2Á3H2O]n), which served as a benchmark ligand with two branches that contain 120 angle dicarboxylic acid in adsorption studies for many years [30,31]. extremities and a third branch with a 90° angle dicarboxylic acid The high stability and porosity of HKUST-1 has spurred research extremity. Consequently, 50,50000-((5-((4-(3,6-dicarboxy-9H-carba into the design of other MOFs with multicarboxylate linkers, zol-9-yl)phenyl)ethynyl)-1,3-phenylene)bis(ethyne-2,1-diyl))bis known as metal multicarboxylate frameworks (MMCFs). Today, ((1,10:30,100-terphenyl]-4,400-dicarboxylic acid), a hexacarboxylate multicarboxylate ligands are widely used in MOF synthesis, and a ligand with 120° and 90° angles (in a ratio of 2:1), was rationally large number of MOFs have been successfully constructed using designed for both the fabrication of the targeted eto MOP and 3D tritopic [30,32,33], tetratopic [34–37], pentatopic [38–41], hex- 18-connected gea-MOF-2 [57]. In another work, the Hupp group atopic [42–45], octatopic [46–48], and even dodecatopic carboxy- showed that the well-established 6-c acs topology (the assembly late ligands [49–51]. The geometries of multicarboxylate linkers of trigonal prismatic metal clusters and ditopic ligands i.e., are dictated by several factors, including the degree of deprotona- MIL-88, MIL-235) can also be synthesized using suitable trigonal tion, hydrogen bond donor/acceptor behavior, size, rigidity, prismatic hexatopic