Design of Pore Size and Functionality in Pillar-Layered Zn-Triazolate-Dicarboxylate Frameworks and Their High CO₂/CH₄ and C2 Hydrocarbons/CH₄ Selectivity

In the design of new materials, those with rare and exceptional compositional and structural features are often highly valued and sought after. On the other hand, materials with common and more accessible modes can often provide richer and unsurpassed compositional and structural variety that makes them a more suitable platform for systematically probing the composition–structure–property correlation. We focus here on one such class of materials, pillar-layered metal–organic frameworks (MOFs), because different pore size and shape as well as functionality can be controlled and adjusted by using pillars with different geometrical and chemical features. Our approach takes advantage of the readily accessible layered Zn-1,2,4-triazolate motif and diverse dicarboxylate ligands with variable length and functional groups, to prepare seven Zn-triazolate-dicarboxylate pillar-layered MOFs. Six different gases (N₂, H₂, CO₂, C₂H₂, C₂H₄, and CH₄) were used to systematically examine the dependency of gas sorption properties on chemical and geometrical properties of those MOFs as well as their potential applications in gas storage and separation. All of these pillar-layered MOFs show not only remarkable CO₂ uptake capacity, but also high CO₂ over CH₄ and C2 hydrocarbons over CH₄ selectivity. An interesting observation is that the BDC ligand (BDC = benzenedicarboxylate) led to a material with the CO₂ uptake outperforming all other metal-triazolate-dicarboxylate MOFs, even though most of them are decorated with amino groups, generally believed to be a key factor for high CO₂ uptake. Overall, the data show that the exploration of the synergistic effect resulting from combined tuning of functional groups and pore size may be a promising strategy to develop materials with the optimum integration of geometrical and chemical factors for the highest possible gas adsorption capacity and separation performance

Systematic and Dramatic Tuning on Gas Sorption Performance in Heterometallic Metal–Organic Frameworks

Despite their having much greater potential for compositional and structural diversity, heterometallic metal–organic frameworks (MOFs) reported so far have lagged far behind their homometallic counterparts in terms of CO₂ uptake performance. Now the power of heterometallic MOFs is in full display, as shown by a series of new materials (denoted CPM-200s) with superior CO₂ uptake capacity (up to 207.6 cm³/g at 273 K and 1 bar), close to the all-time record set by MOF-74-Mg. The isosteric heat of adsorption can also be tuned from −16.4 kJ/mol for CPM-200-Sc/Mg to −79.6 kJ/mol for CPM-200-V/Mg. The latter value is the highest reported for MOFs with Lewis acid sites. Some members of the CPM-200s family consist of combinations of metal ions (e.g., Mg/Ga, Mg/Fe, Mg/V, Mg/Sc) that have never been shown to coexist in any known crystalline porous materials. Such previously unseen combinations become reality through a cooperative crystallization process, which leads to the most intimate form of integration between even highly dissimilar metals, such as Mg²⁺ and V³⁺. The synergistic effects of heterometals bestow CPM-200s with the highest CO₂ uptake capacity among known heterometallic MOFs and place them in striking distance of the all-time CO₂ uptake record

Systematic and Dramatic Tuning on Gas Sorption Performance in Heterometallic Metal–Organic Frameworks

Despite their having much greater potential for compositional and structural diversity, heterometallic metal–organic frameworks (MOFs) reported so far have lagged far behind their homometallic counterparts in terms of CO₂ uptake performance. Now the power of heterometallic MOFs is in full display, as shown by a series of new materials (denoted CPM-200s) with superior CO₂ uptake capacity (up to 207.6 cm³/g at 273 K and 1 bar), close to the all-time record set by MOF-74-Mg. The isosteric heat of adsorption can also be tuned from −16.4 kJ/mol for CPM-200-Sc/Mg to −79.6 kJ/mol for CPM-200-V/Mg. The latter value is the highest reported for MOFs with Lewis acid sites. Some members of the CPM-200s family consist of combinations of metal ions (e.g., Mg/Ga, Mg/Fe, Mg/V, Mg/Sc) that have never been shown to coexist in any known crystalline porous materials. Such previously unseen combinations become reality through a cooperative crystallization process, which leads to the most intimate form of integration between even highly dissimilar metals, such as Mg²⁺ and V³⁺. The synergistic effects of heterometals bestow CPM-200s with the highest CO₂ uptake capacity among known heterometallic MOFs and place them in striking distance of the all-time CO₂ uptake record

Pore Space Partition by Symmetry-Matching Regulated Ligand Insertion and Dramatic Tuning on Carbon Dioxide Uptake

Metal–organic frameworks (MOFs) with the highest CO₂ uptake capacity are usually those equipped with open metal sites. Here we seek alternative strategies and mechanisms for developing high-performance CO₂ adsorbents. We demonstrate that through a ligand insertion pore space partition strategy, we can create crystalline porous materials (CPMs) with superior CO₂ uptake capacity. Specifically, a new material, CPM-33b-Ni without any open metal sites, exhibits the CO₂ uptake capacity comparable to MOF-74 with the same metal (Ni) at 298 K and 1 bar

Synthesis, Crystal Structures, and Solid-State Luminescent Properties of Diverse Ln–Pyridine-3,5-Dicarboxylate Coordination Polymers Modulated by the Ancillary Ligand

Nine members of the novel Ln–pyridine-3,5-dicarboxylate coordination polymer family, namely, [Ln­(PDC)­(GA)]_<i>n</i> (Ln = Gd (<b>1</b>), Tb (<b>2</b>), Dy (<b>3</b>), Er (<b>4</b>)), [Ln­(PDC)­(OAc)­(H₂O)]_<i>n</i>·<i>n</i>H₂O (Ln = Sm (<b>5</b>), Eu (<b>6</b>), Gd (<b>7</b>)), [Gd­(PDC)­(OAc)­(H₂O)₂]_<i>n</i>·<i>n</i>H₂O (<b>8</b>), and [Tb­(PDC)_1.5­(H₂O)]_<i>n</i> (<b>9</b>) (PDC = pyridine-3,5-dicarboxylate, GA = glycolate, OAc = acetate), have been successfully obtained by carefully regulating the ancillary ligand or reaction temperatures. Complexes <b>1</b>–<b>4</b> are isomorphous two-dimensional networks generated by Ln–glycolate chains and bridging PDC ligands. When the HOAc was utilized instead of glycolic acid, isomorphic three-dimensional compounds <b>5</b>–<b>7</b> were isolated. The Ln³⁺ atoms are first bridged by acetate anions to give dinuclear clusters, which are extended by nearby six PDC ligands forming a 3D (3,6)-connected <i>flu-</i>topological framework. Notably, the increase of reaction temperature from 160 to 180 °C during the synthesis of compound <b>7</b> led to compound <b>8</b>, the other 3D (3,6)-connected structure on the base of dinuclear subunits with <i>rtl</i> topology. Furthermore, the absence of HOAc introduced the formation of compound <b>9</b>, in which each binuclear cluster links adjacent eight PDC anions to give a 3D (3,8)-connected <i>tfz-d</i> topological structure. The elemental analyses, XRPD, FT-IR, and TGA were also investigated to characterize compounds <b>1</b>–<b>9</b>. Furthermore, solid-state photoluminescence measurements show that these Ln–pyridine-3,5-dicarboxylate coordination polymers produce strong emissions at room temperature

Synthesis, Crystal Structures, and Solid-State Luminescent Properties of Diverse Ln–Pyridine-3,5-Dicarboxylate Coordination Polymers Modulated by the Ancillary Ligand

Nine members of the novel Ln–pyridine-3,5-dicarboxylate coordination polymer family, namely, [Ln­(PDC)­(GA)]_<i>n</i> (Ln = Gd (<b>1</b>), Tb (<b>2</b>), Dy (<b>3</b>), Er (<b>4</b>)), [Ln­(PDC)­(OAc)­(H₂O)]_<i>n</i>·<i>n</i>H₂O (Ln = Sm (<b>5</b>), Eu (<b>6</b>), Gd (<b>7</b>)), [Gd­(PDC)­(OAc)­(H₂O)₂]_<i>n</i>·<i>n</i>H₂O (<b>8</b>), and [Tb­(PDC)_1.5­(H₂O)]_<i>n</i> (<b>9</b>) (PDC = pyridine-3,5-dicarboxylate, GA = glycolate, OAc = acetate), have been successfully obtained by carefully regulating the ancillary ligand or reaction temperatures. Complexes <b>1</b>–<b>4</b> are isomorphous two-dimensional networks generated by Ln–glycolate chains and bridging PDC ligands. When the HOAc was utilized instead of glycolic acid, isomorphic three-dimensional compounds <b>5</b>–<b>7</b> were isolated. The Ln³⁺ atoms are first bridged by acetate anions to give dinuclear clusters, which are extended by nearby six PDC ligands forming a 3D (3,6)-connected <i>flu-</i>topological framework. Notably, the increase of reaction temperature from 160 to 180 °C during the synthesis of compound <b>7</b> led to compound <b>8</b>, the other 3D (3,6)-connected structure on the base of dinuclear subunits with <i>rtl</i> topology. Furthermore, the absence of HOAc introduced the formation of compound <b>9</b>, in which each binuclear cluster links adjacent eight PDC anions to give a 3D (3,8)-connected <i>tfz-d</i> topological structure. The elemental analyses, XRPD, FT-IR, and TGA were also investigated to characterize compounds <b>1</b>–<b>9</b>. Furthermore, solid-state photoluminescence measurements show that these Ln–pyridine-3,5-dicarboxylate coordination polymers produce strong emissions at room temperature

Synthesis, Crystal Structures, and Solid-State Luminescent Properties of Diverse Ln–Pyridine-3,5-Dicarboxylate Coordination Polymers Modulated by the Ancillary Ligand

Nine members of the novel Ln–pyridine-3,5-dicarboxylate coordination polymer family, namely, [Ln­(PDC)­(GA)]_<i>n</i> (Ln = Gd (<b>1</b>), Tb (<b>2</b>), Dy (<b>3</b>), Er (<b>4</b>)), [Ln­(PDC)­(OAc)­(H₂O)]_<i>n</i>·<i>n</i>H₂O (Ln = Sm (<b>5</b>), Eu (<b>6</b>), Gd (<b>7</b>)), [Gd­(PDC)­(OAc)­(H₂O)₂]_<i>n</i>·<i>n</i>H₂O (<b>8</b>), and [Tb­(PDC)_1.5­(H₂O)]_<i>n</i> (<b>9</b>) (PDC = pyridine-3,5-dicarboxylate, GA = glycolate, OAc = acetate), have been successfully obtained by carefully regulating the ancillary ligand or reaction temperatures. Complexes <b>1</b>–<b>4</b> are isomorphous two-dimensional networks generated by Ln–glycolate chains and bridging PDC ligands. When the HOAc was utilized instead of glycolic acid, isomorphic three-dimensional compounds <b>5</b>–<b>7</b> were isolated. The Ln³⁺ atoms are first bridged by acetate anions to give dinuclear clusters, which are extended by nearby six PDC ligands forming a 3D (3,6)-connected <i>flu-</i>topological framework. Notably, the increase of reaction temperature from 160 to 180 °C during the synthesis of compound <b>7</b> led to compound <b>8</b>, the other 3D (3,6)-connected structure on the base of dinuclear subunits with <i>rtl</i> topology. Furthermore, the absence of HOAc introduced the formation of compound <b>9</b>, in which each binuclear cluster links adjacent eight PDC anions to give a 3D (3,8)-connected <i>tfz-d</i> topological structure. The elemental analyses, XRPD, FT-IR, and TGA were also investigated to characterize compounds <b>1</b>–<b>9</b>. Furthermore, solid-state photoluminescence measurements show that these Ln–pyridine-3,5-dicarboxylate coordination polymers produce strong emissions at room temperature

Synthesis, Crystal Structures, and Solid-State Luminescent Properties of Diverse Ln–Pyridine-3,5-Dicarboxylate Coordination Polymers Modulated by the Ancillary Ligand

Nine members of the novel Ln–pyridine-3,5-dicarboxylate coordination polymer family, namely, [Ln­(PDC)­(GA)]_<i>n</i> (Ln = Gd (<b>1</b>), Tb (<b>2</b>), Dy (<b>3</b>), Er (<b>4</b>)), [Ln­(PDC)­(OAc)­(H₂O)]_<i>n</i>·<i>n</i>H₂O (Ln = Sm (<b>5</b>), Eu (<b>6</b>), Gd (<b>7</b>)), [Gd­(PDC)­(OAc)­(H₂O)₂]_<i>n</i>·<i>n</i>H₂O (<b>8</b>), and [Tb­(PDC)_1.5­(H₂O)]_<i>n</i> (<b>9</b>) (PDC = pyridine-3,5-dicarboxylate, GA = glycolate, OAc = acetate), have been successfully obtained by carefully regulating the ancillary ligand or reaction temperatures. Complexes <b>1</b>–<b>4</b> are isomorphous two-dimensional networks generated by Ln–glycolate chains and bridging PDC ligands. When the HOAc was utilized instead of glycolic acid, isomorphic three-dimensional compounds <b>5</b>–<b>7</b> were isolated. The Ln³⁺ atoms are first bridged by acetate anions to give dinuclear clusters, which are extended by nearby six PDC ligands forming a 3D (3,6)-connected <i>flu-</i>topological framework. Notably, the increase of reaction temperature from 160 to 180 °C during the synthesis of compound <b>7</b> led to compound <b>8</b>, the other 3D (3,6)-connected structure on the base of dinuclear subunits with <i>rtl</i> topology. Furthermore, the absence of HOAc introduced the formation of compound <b>9</b>, in which each binuclear cluster links adjacent eight PDC anions to give a 3D (3,8)-connected <i>tfz-d</i> topological structure. The elemental analyses, XRPD, FT-IR, and TGA were also investigated to characterize compounds <b>1</b>–<b>9</b>. Furthermore, solid-state photoluminescence measurements show that these Ln–pyridine-3,5-dicarboxylate coordination polymers produce strong emissions at room temperature

Synthesis, Crystal Structures, and Solid-State Luminescent Properties of Diverse Ln–Pyridine-3,5-Dicarboxylate Coordination Polymers Modulated by the Ancillary Ligand

Nine members of the novel Ln–pyridine-3,5-dicarboxylate coordination polymer family, namely, [Ln­(PDC)­(GA)]_<i>n</i> (Ln = Gd (<b>1</b>), Tb (<b>2</b>), Dy (<b>3</b>), Er (<b>4</b>)), [Ln­(PDC)­(OAc)­(H₂O)]_<i>n</i>·<i>n</i>H₂O (Ln = Sm (<b>5</b>), Eu (<b>6</b>), Gd (<b>7</b>)), [Gd­(PDC)­(OAc)­(H₂O)₂]_<i>n</i>·<i>n</i>H₂O (<b>8</b>), and [Tb­(PDC)_1.5­(H₂O)]_<i>n</i> (<b>9</b>) (PDC = pyridine-3,5-dicarboxylate, GA = glycolate, OAc = acetate), have been successfully obtained by carefully regulating the ancillary ligand or reaction temperatures. Complexes <b>1</b>–<b>4</b> are isomorphous two-dimensional networks generated by Ln–glycolate chains and bridging PDC ligands. When the HOAc was utilized instead of glycolic acid, isomorphic three-dimensional compounds <b>5</b>–<b>7</b> were isolated. The Ln³⁺ atoms are first bridged by acetate anions to give dinuclear clusters, which are extended by nearby six PDC ligands forming a 3D (3,6)-connected <i>flu-</i>topological framework. Notably, the increase of reaction temperature from 160 to 180 °C during the synthesis of compound <b>7</b> led to compound <b>8</b>, the other 3D (3,6)-connected structure on the base of dinuclear subunits with <i>rtl</i> topology. Furthermore, the absence of HOAc introduced the formation of compound <b>9</b>, in which each binuclear cluster links adjacent eight PDC anions to give a 3D (3,8)-connected <i>tfz-d</i> topological structure. The elemental analyses, XRPD, FT-IR, and TGA were also investigated to characterize compounds <b>1</b>–<b>9</b>. Furthermore, solid-state photoluminescence measurements show that these Ln–pyridine-3,5-dicarboxylate coordination polymers produce strong emissions at room temperature

Synthesis, Crystal Structures, and Solid-State Luminescent Properties of Diverse Ln–Pyridine-3,5-Dicarboxylate Coordination Polymers Modulated by the Ancillary Ligand

Nine members of the novel Ln–pyridine-3,5-dicarboxylate coordination polymer family, namely, [Ln­(PDC)­(GA)]_<i>n</i> (Ln = Gd (<b>1</b>), Tb (<b>2</b>), Dy (<b>3</b>), Er (<b>4</b>)), [Ln­(PDC)­(OAc)­(H₂O)]_<i>n</i>·<i>n</i>H₂O (Ln = Sm (<b>5</b>), Eu (<b>6</b>), Gd (<b>7</b>)), [Gd­(PDC)­(OAc)­(H₂O)₂]_<i>n</i>·<i>n</i>H₂O (<b>8</b>), and [Tb­(PDC)_1.5­(H₂O)]_<i>n</i> (<b>9</b>) (PDC = pyridine-3,5-dicarboxylate, GA = glycolate, OAc = acetate), have been successfully obtained by carefully regulating the ancillary ligand or reaction temperatures. Complexes <b>1</b>–<b>4</b> are isomorphous two-dimensional networks generated by Ln–glycolate chains and bridging PDC ligands. When the HOAc was utilized instead of glycolic acid, isomorphic three-dimensional compounds <b>5</b>–<b>7</b> were isolated. The Ln³⁺ atoms are first bridged by acetate anions to give dinuclear clusters, which are extended by nearby six PDC ligands forming a 3D (3,6)-connected <i>flu-</i>topological framework. Notably, the increase of reaction temperature from 160 to 180 °C during the synthesis of compound <b>7</b> led to compound <b>8</b>, the other 3D (3,6)-connected structure on the base of dinuclear subunits with <i>rtl</i> topology. Furthermore, the absence of HOAc introduced the formation of compound <b>9</b>, in which each binuclear cluster links adjacent eight PDC anions to give a 3D (3,8)-connected <i>tfz-d</i> topological structure. The elemental analyses, XRPD, FT-IR, and TGA were also investigated to characterize compounds <b>1</b>–<b>9</b>. Furthermore, solid-state photoluminescence measurements show that these Ln–pyridine-3,5-dicarboxylate coordination polymers produce strong emissions at room temperature