Thermally Stable Porous Hydrogen‐Bonded Coordination Networks Displaying Dual Properties of Robustness and Dynamics upon Guest Uptake

Abstract

Two series of microporous lanthanide coordination networks of the general formula, {[Ln(ntb)Cl(3)] x xH(2)O}(n) (series 1: monoclinic C2/c, Ln = Sm and Tb; series 2: hexagonal P3(1)/c, Ln = Sm and Eu; ntb = tris(benzimidazol-2-ylmethyl)amine, x = 0-4) have been synthesized and characterized by IR, elemental analyses, thermal gravimetry, and single-crystal and powder X-ray diffraction methods. In both series, the monomeric [Ln(ntb)Cl(3)] coordination units are consolidated by N-H...Cl or C-H...Cl hydrogen bonds to sustain three-dimensional (3D) networks. However, the different modes of hydrogen bonding in the two series lead to crystallization of the same [Ln(ntb)Cl(3)] monomers in different forms (monoclinic vs. hexagonal), consequently giving rise to distinct porous structures. The resulting hydrogen-bonded coordination networks display high thermal stability and robustness in water removal/inclusion processes, which was confirmed by temperature-dependent single-crystal-to-single-crystal transformation measurements. Adsorption studies with H(2), CO(2), and MeOH have been carried out, and reveal distinct differences in adsorption behavior between the two forms. In the case of MeOH uptake, the monoclinic network shows a normal type I isotherm, whereas the hexagonal network displays dynamic porous properties.

Crystal structure of catena-poly[diaquabis(μ2-3-carboxybenzene-1,2-dicarboxylato-1:2κ2 O:O′)-(μ2-1,4-bis(2-ethylbenzimidazol-1-ylmethyl)-benzene-1:1′κ2 N:N′)dizinc(II)], [Zn2(C26H26N4)(C9H4O6)2(H2O)2]

“…Hitherto, much e ort has been done on the rational design and controlled synthesis of desired and attractive coordination polymers [5,6]. And it indicates that the selection of multifunctional organic ligands containing appropriate coordination sites and proper spacers would be critical step to get complexes with versatile structures and desired properties [7][8][9].…”

Recent advance in porous coordination polymers from the viewpoint of crystalline-state transformation

“…[124] [ Thermally stable porous hydrogen-bonded coordination networks displaying dual properties of robustness and dynamics upon guest uptake. [87] Temperature-dependent guest-driven single-crystal-to-single-crystal ligand exchange in a two-fold interpenetrated Cd II grid network. [127] BAI JunFeng Nanjing University Topology diversity and reversible crystal-to-amorphous transformation properties of 3D cobalt coordination polymers from a series of 1D rodlike dipyridyl-containing building blocks and a flexible tripodal acid with additional amide groups.…”

“…Metal cluster was generally connected by counterbalance ions or stable through weak interaction such as hydrogen bond. Though very few low-dimensional structure have demonstrated permanent porosity since intermolecular coulombic/van der Waals interactions are usually too weak for sustaining an open framework [86,87], in some case, guest molecules which act as template were found in metal clusters, and void space was provided by removing the guest molecules in an appropriate manner [88]. Leonard J. Barbour and co-workers reported two discrete metallocyclic complex [Ag 2 L 2 ](BF 4 ) 2 ·2CH 3 CN (16, L = 1,4-bis(2-methylimidazol-1-ylmethyl)benzene)) ( Figure 14(b)) and [Cu 2 (bitmb) 2 Cl 4 ]·CH 3 OH·H 2 O (17, bitmb =1,3-bis(imidazol-1-ylmethyl)-2,4,6-trimethylbenzene) which retained their solvent-templated channel structure on guest removal to yield porous, gas sorbing material [89,90].…”

A novel POM-based inorganic porous framework: Synthesis, structure and properties

“…The magnetic behavior of 1 is antiferromagnetic coupling. Futhermore, compound 1 exhibits good thermal stability and active electrochemical behavior.In the past decade, metal-organic frameworks (MOFs), as a new class of crystalline porous materials, have become one of the most prolific areas of research in chemistry and materials [1,2]. Through the combination of diverse metal-based building units and numerous organic linkers, MOFs possess rich structures and adjustable pore size, which are quite different from traditional porous zeolites [3].…”