Search

The solvothermal reactions of ZnCl2·6H2O, benzene-1,3,5-tribenzoic acid (H3btb), and N-heterocyclic ancillary imidazole (Im) or aminopyrimidine (a mp) ligands led to the creation of two-dimensional (2D) zinc(II) based metal–organic frameworks (MOFs), (Me2NH2)2[Zn2(btb)2(Im)2]·2DMF·3MeOH (1) and (Me2NH2)2[Zn2(btb)2(amp)]·H2O·2DMF·MeOH (2). The btb3− ligands in 1 and 2 form an anionic 2D layered structure with a (63) honeycomb (hcb) topology by linking to Zn(II) centres through their carboxylate groups. The incorporation of N-heterocyclic auxiliary ligands Im and amp into the hcb nets resulted in the formation of a 2D hydrogen-bonded and covalently pillared bilayer structure featuring two-fold interpenetrating networks. Each of these networks consists of small channels that are occupied by Me2NH2 cations and solvent molecules. Both 1 and 2 emit blue luminescence emissions in the solid state at room temperature and exhibit a great selectivity and sensitivity for the detection of acetone and multiple heavy metal ions including Hg2+, Cu2+, Fe2+, Pb2+, Cr3+, and Fe3+ ions. At 1 bar, activated 1 and 2 demonstrate moderate capacities for adsorbing CO2 at room temperature, with a preference for CO2 over N2. Notably, at higher pressures (up to 20 bar), their activated samples 1 and 2 show a temperature-dependent enhancement of CO2 uptake while retaining good stability. [ABSTRACT FROM AUTHOR]

Two neodymium sulfate based purely inorganic networks, [NH4][Nd(SO4)2(H2O)3] ⋅ H2O (1) and [Nd2(SO4)3(H2O)4] ⋅ H2O (2) have been synthesized at different reaction temperatures and pH values. The structure of 1 features a two‐dimensional (2D) anionic corrugated sheet with an sql topological net built up by linking NdO8 units and μ2‐SO42− anions, in which the NH4+ charge‐compensating/templating cations occupy the intersheet layers. While 2 possesses a 3D neutral framework with an unprecedented (3,42,7‐c) net constructed by NdO9 units and μ4‐ and μ6‐SO42− linkers. They exhibit thermally induced irreversible structural transformation associated with the dehydration and the changes in coordination geometry and dimensionality. Both compound 1 and 2 display typical antiferromagnetic interactions between the Nd3+ centres. In addition, the CO2 adsorption isotherms of the desolvated samples 1 and 2 were also investigated. [ABSTRACT FROM AUTHOR]

We report the synthesis, crystal structures, and properties of three lanthanide(III) coordination complexes based on 2‐thiopheneacrylic acid (Htpa) of the formula [Ln(tpa)3(H2O)3] ⋅ 3(Htpa) (Ln=Tb (1), Dy (2), Er (3)). The complexes were characterized by single crystal X‐ray diffraction, powder X‐ray diffraction, elemental analysis, IR, TGA, and photoluminescence spectroscopy. Structural analysis indicates that all three complexes are isostructural and crystallize in the trigonal space group R3. The structures of these complexes consist of a discrete neutral mononuclear species [Ln(tpa)3(H2O)3] and the Htpa molecule. In the crystal, the complex species are self‐assembled into a one‐dimensional (1D) supramolecular chain through classical O−H⋅⋅⋅O hydrogen bonds existing between water molecules and carboxylate oxygen atoms. The adjacent chains are further joined together by C−H⋅⋅⋅π hydrogen bonds involving the thiophene moieties, resulting in the formation of a 3D supramolecular framework. The frameworks feature 1D channels with a dimeter of ca. 1.5 nm that can accommodate Htpa molecules to allow the formation of cocrystals via strong hydrogen bonds. In addition, the solid‐state luminescence and thermal properties of these complexes were also investigated. [ABSTRACT FROM AUTHOR]

Four isostructural dinuclear M2L2 mesocates of the general formula [M2(NCS)4(L)2]·4.5MeOH (1M; M = Mn, Fe, Co, Zn) were constructed by using the coordination-driven self-assembly of the [M(NCS)2] precursor and the flexible bis-bidentate pyridylimine Schiff base ligand L (L = 4,4′-(1,4-phenylenebis(oxy))bis(N-(pyridin-2-ylmethylene)aniline). The centrosymmetric M2L2 mesocate forms through the side-by-side coordination of two L ligands to a pair of M(II) ions. The mesocates exhibit a reversible temperature induced desolvation–solvation behavior without losing their structural integrity. The activated 1Co, as the representative M2L2 mesocate, shows an exceptionally high MeOH vapour uptake capacity of 481.9 cm3 g−1 (68.8 wt%) at STP with good recyclability. Notably, it also exhibits CO2 adsorption with an uptake capacity of 20.2 cm3 g−1 (3.6 wt%) at room temperature and 1 bar. [ABSTRACT FROM AUTHOR]

Over the past two decades, the development of novel inorganic–organic hybrid porous crystalline materials or metal–organic frameworks (MOFs) using crystal engineering has provoked significant interest due to their potential applications as functional materials. In this context, luminescent MOFs as fluorescence sensors have recently received significant attention for the sensing of ionic species and small molecules. In this work, a new luminescent heterometallic zinc(II)–barium(II)‐based anionic metal–organic framework, namely poly[imidazolium [triaqua(μ6‐benzene‐1,3,5‐tricarboxylato)bariumtrizinc] tetrahydrate], {(C3H4N2)[BaZn3(C9H3O6)3(H2O)3]·4H2O}n (1), was synthesized under hydrothermal conditions and characterized. Compound 1 presents a three‐dimensional framework with an unprecedented (3,5)‐connected topology of the point symbol (3.92).(33.42.5.93.10), and exhibits 'turn‐off' luminescence responses for the Cu2+ and Fe3+ ions in aqueous solution based on significantly different quenching mechanisms. [ABSTRACT FROM AUTHOR]

Two new lanthanide-based coordination polymers, [Sm2(bzz)(ben)6(H2O)3]·0.5H2O (1) and [Eu(bbz)(ben)3] (2), were synthesized and characterized. The described products were formed from in situ-generated benzoate (ben) and N'-benzoylbenzohydrazide (bbz) ligands, which were the products of transformation of originally added benzhydrazide (bzz) under hydrothermal conditions. Compound 1 exhibits a one-dimensional (1D) double-chain structure built up from the connection of the central Sm3+ ions with a mixture of bzz and ben ligands. On the other hand, 2 features a 3D network with a 4-connected (66) dia topology constructed from dinuclear [Eu2(ben)6] secondary building units and bbz linkers. High-pressure CO2 sorption studies of activated 1 show that maximum uptake increases to exceptionally high values of 376.7 cm3 g−1 (42.5 wt%) under a pressure of 50 bar at 298 K with good recyclability. Meanwhile, 2 shows a typical red emission in the solid state at room temperature with the decay lifetime of 1.2 ms. [ABSTRACT FROM AUTHOR]

The solvothermal reactions of ZnCl 2 ·6H 2 O, benzene-1,3,5-tribenzoic acid (H 3 btb), and N-heterocyclic ancillary imidazole (Im) or aminopyrimidine (a mp) ligands led to the creation of two-dimensional (2D) zinc(II) based metal-organic frameworks (MOFs), (Me 2 NH 2 ) 2 [Zn 2 (btb) 2 (Im) 2 ]·2DMF·3MeOH (1) and (Me 2 NH 2 ) 2 [Zn 2 (btb) 2 (amp)]·H 2 O·2DMF·MeOH (2). The btb 3- ligands in 1 and 2 form an anionic 2D layered structure with a (6 3 ) honeycomb (hcb) topology by linking to Zn(II) centres through their carboxylate groups. The incorporation of N-heterocyclic auxiliary ligands Im and amp into the hcb nets resulted in the formation of a 2D hydrogen-bonded and covalently pillared bilayer structure featuring two-fold interpenetrating networks. Each of these networks consists of small channels that are occupied by Me 2 NH 2 cations and solvent molecules. Both 1 and 2 emit blue luminescence emissions in the solid state at room temperature and exhibit a great selectivity and sensitivity for the detection of acetone and multiple heavy metal ions including Hg 2+ , Cu 2+ , Fe 2+ , Pb 2+ , Cr 3+ , and Fe 3+ ions. At 1 bar, activated 1 and 2 demonstrate moderate capacities for adsorbing CO 2 at room temperature, with a preference for CO 2 over N 2 . Notably, at higher pressures (up to 20 bar), their activated samples 1 and 2 show a temperature-dependent enhancement of CO 2 uptake while retaining good stability.

Four isostructural dinuclear M2L2 mesocates of the general formula [M2(NCS)4(L)2]·4.5MeOH (1M; M = Mn, Fe, Co, Zn) were constructed by using the coordination-driven self-assembly of the [M(NCS)2] precursor and the flexible bis-bidentate pyridylimine Schiff base ligand L (L = 4,4'-(1,4-phenylenebis(oxy))bis(N-(pyridin-2-ylmethylene)aniline). The centrosymmetric M2L2 mesocate forms through the side-by-side coordination of two L ligands to a pair of M(ii) ions. The mesocates exhibit a reversible temperature induced desolvation-solvation behavior without losing their structural integrity. The activated 1Co, as the representative M2L2 mesocate, shows an exceptionally high MeOH vapour uptake capacity of 481.9 cm3 g-1 (68.8 wt%) at STP with good recyclability. Notably, it also exhibits CO2 adsorption with an uptake capacity of 20.2 cm3 g-1 (3.6 wt%) at room temperature and 1 bar.

Over the past two decades, the development of novel inorganic-organic hybrid porous crystalline materials or metal-organic frameworks (MOFs) using crystal engineering has provoked significant interest due to their potential applications as functional materials. In this context, luminescent MOFs as fluorescence sensors have recently received significant attention for the sensing of ionic species and small molecules. In this work, a new luminescent heterometallic zinc(II)-barium(II)-based anionic metal-organic framework, namely poly[imidazolium [triaqua(μ 6 -benzene-1,3,5-tricarboxylato)bariumtrizinc] tetrahydrate], {(C 3 H 4 N 2 )[BaZn 3 (C 9 H 3 O 6 ) 3 (H 2 O) 3 ]·4H 2 O} n (1), was synthesized under hydrothermal conditions and characterized. Compound 1 presents a three-dimensional framework with an unprecedented (3,5)-connected topology of the point symbol (3.9 2 ).(3 3 .4 2 .5.9 3 .10), and exhibits `turn-off' luminescence responses for the Cu 2+ and Fe 3+ ions in aqueous solution based on significantly different quenching mechanisms.