Amine-Templated Assembly of Metal–Organic Frameworks with Attractive Topologies

Abstract

Seven new metal–organic frameworks (MOFs) have been synthesized using different organic amines as templates: [Cd(HBTC)2]·2(HDETA)·4(H2O) (1) (BTC = 1,3,5-benzenetricarboxylate and DETA = diethylenetriamine), [Cd2(BTC)2(H2O)2]·2(HCHA)·2(EtOH)·2(H2O) (CHA = cyclohexylamine) (2), [Cd5(BTC)4Cl4]·4(HTEA)·2(H3O) (TEA = triethylamine) (3), [Cd3(BTC)3(H2O)]·(HTEA)·2(H3O) (4), [Zn(BTC)(H2O)]·(HTPA)·(H2O) (TPA = tri-n-propylamine) (5), [Cd(BTC)]·(HTPA)·(H2O) (6), and [Cd2(BTC)(HBTC)]·(HTBA)·(H2O) (TBA = tri-n-butylamine) (7). Topologically, the polymer 1 exhibits a two-dimensional (2D) Cd-HBTC network with (44) topology, which is a sql structure; the polymer 2 possesses a three-dimensional (3D) porous Cd-BTC framework with (4·62)2(42·610·83) topology, which is a contorted rutile structure; polymer 3 exhibits a 3D open Cd-BTC architecture with (62·82·102)2(62·84)(63)4 topology; polymer 4 is a 3D porous Cd-BTC network with new (4·62)2(42·64·86·103)(6·82)2(62·84)(62·84)2(62·8)2 topology; similar to 1, polymer 5 is a 2D Zn-BTC framework with (4·82) topology; interestingly, polymer 6 possesses a 3D porous Cd-BTC architecture with the same topology as 2; polymer 7 shows a 3D open Cd-BTC framework with (63)(65·10) topology. In addition to the structures of polymers 1–7, their thermal stabilities, ion exchange properties, and nonbonding interaction energies, including H-bonding and van der Waals, have also been studied. Remarkably, those organic amine cations reside in the interlayer or channel space, playing important roles such as templating, space-filling, and charge-balancing agents. These studies would facilitate the exploration of novel MOFs with charming molecular topologies and multifunctional properties.