16 research outputs found
Direct Solvent-Free Regioselective Construction of Pyrrolo[1,2‑<i>a</i>][1,10]phenanthrolines Based on Isocyanide-Based Multicomponent Reactions
A novel efficient one-pot four-component regioselective synthesis of pyrrolo[1,2-<i>a</i>][1,10]phenanthrolines in excellent yields has been developed by 1,3-dipolar cycloaddition of aldehydes, malononitrile, and isocyanides with 1,10-phenanthroline under solvent-free conditions within 3 min without using any catalyst or activation. The products were preliminarily investigated as chromogenic and fluorescent sensors for Cu<sup>2+</sup> ions
Direct Solvent-Free Regioselective Construction of Pyrrolo[1,2‑<i>a</i>][1,10]phenanthrolines Based on Isocyanide-Based Multicomponent Reactions
A novel efficient one-pot four-component regioselective synthesis of pyrrolo[1,2-<i>a</i>][1,10]phenanthrolines in excellent yields has been developed by 1,3-dipolar cycloaddition of aldehydes, malononitrile, and isocyanides with 1,10-phenanthroline under solvent-free conditions within 3 min without using any catalyst or activation. The products were preliminarily investigated as chromogenic and fluorescent sensors for Cu<sup>2+</sup> ions
One-Pot Multicomponent Cascade Reaction of <i>N,S</i>-Ketene Acetal: Solvent-Free Synthesis of Imidazo[1,2-<i>a</i>]thiochromeno[3,2-<i>e</i>]pyridines
Unprecedented imidazo[1,2-<i>a</i>]thiochromeno[3,2-<i>e</i>]pyridines have been synthesized via a three-component cascade reaction under solvent-free conditions. This one-pot transformation involving multiple steps and not requiring the use of transition metal catalysts constructs three new C–C bonds, two C–N bonds, one C–S bond, and three new rings with all reactants efficiently utilized
Tuning CO<sub>2</sub> Selective Adsorption over N<sub>2</sub> and CH<sub>4</sub> in UiO-67 Analogues through Ligand Functionalization
Introducing functional groups into
pores of metal–organic frameworks (MOFs) through ligand modification
provides an efficacious approach for tuning gas adsorption and separation
performances of this type of novel porous material. In this work,
two UiO-67 analogues, [Zr<sub>6</sub>O<sub>4</sub>(OH)<sub>4</sub>(FDCA)<sub>6</sub>] (BUT-10) and [Zr<sub>6</sub>O<sub>4</sub>(OH)<sub>4</sub>(DTDAO)<sub>6</sub>] (BUT-11), with functionalized pore surfaces
and high stability were synthesized from two functional ligands, 9-fluorenone-2,7-dicarboxylic
acid (H<sub>2</sub>FDCA) and dibenzoÂ[<i>b</i>,<i>d</i>]Âthiophene-3,7-dicarboxylic acid 5,5-dioxide (H<sub>2</sub>DTDAO),
respectively, and structurally determined by single-crystal X-ray
diffraction. Notwithstanding skeleton bend of the two ligands relative
to the linear 4,4′-biphenyldicarboxylic acid in UiO-67, the
two MOFs have structures similar to that of UiO-67, with only lowered
symmetry in their frameworks. Attributed to these additional functional
groups (carbonyl and sulfone, respectively) in the ligands, BUT-10
and -11 show enhanced CO<sub>2</sub> adsorption and separation selectivities
over N<sub>2</sub> and CH<sub>4</sub>, in spite of decreased pore
sizes and surface areas compared with UiO-67. At 298 K and 1 atm,
the CO<sub>2</sub> uptake is 22.9, 50.6, and 53.5 cm<sup>3</sup>/g,
and the infinite dilution selectivities of CO<sub>2</sub>/CH<sub>4</sub> are 2.7, 5.1, and 9.0 and those of CO<sub>2</sub>/N<sub>2</sub> are
9.4, 18.6, and 31.5 for UiO-67, BUT-10, and BUT-11, respectively.
The selectivities of CO<sub>2</sub>/CH<sub>4</sub> and CO<sub>2</sub>/N<sub>2</sub> are thus enhanced 1.9 and 2.0 times in BUT-10 and
3.3 and 3.4 times in BUT-11, respectively, on the basis of UiO-67.
The adsorption mechanism of CO<sub>2</sub> in BUT-11 has also been
explored through computational simulations. The results show that
CO<sub>2</sub> molecules locate around the sulfone groups in pore
surfaces of BUT-11, verifying at the molecular level that sulfone
groups significantly increase the affinity toward CO<sub>2</sub> molecules
of the framework. This provides thus an efficient strategy for the
design of CO<sub>2</sub> capture materials
Tuning Water Sorption in Highly Stable Zr(IV)-Metal–Organic Frameworks through Local Functionalization of Metal Clusters
Water
adsorption of metal–organic frameworks (MOFs) is attracting
intense interest because of their potential applications in atmospheric
water harvesting, dehumidification, and adsorption-based heating and
cooling. In this work, through using a hexacarboxylate ligand, four
new isostructural ZrÂ(IV)-MOFs (BUT-46F, -46A, -46W, and -46B) with
rare low-symmetric 9-connected Zr<sub>6</sub> clusters were synthesized
and structurally characterized. These MOFs are highly stable in water,
HCl aqueous solution (pH = 1), and NaOH aqueous solution (pH = 10)
at room temperature, as well as in boiling water. Interestingly, the
rational modification of the metal clusters in these MOFs with different
functional groups (HCOO<sup>–</sup>, CH<sub>3</sub>COO<sup>–</sup>, H<sub>2</sub>O/OH, and PhCOO<sup>–</sup>)
enables the precise tuning of their water adsorption properties, which
is quite important for given application. Furthermore, all four MOFs
show excellent regenerability under mild conditions and good cyclic
performance in water adsorption
Tuning Water Sorption in Highly Stable Zr(IV)-Metal–Organic Frameworks through Local Functionalization of Metal Clusters
Water
adsorption of metal–organic frameworks (MOFs) is attracting
intense interest because of their potential applications in atmospheric
water harvesting, dehumidification, and adsorption-based heating and
cooling. In this work, through using a hexacarboxylate ligand, four
new isostructural ZrÂ(IV)-MOFs (BUT-46F, -46A, -46W, and -46B) with
rare low-symmetric 9-connected Zr<sub>6</sub> clusters were synthesized
and structurally characterized. These MOFs are highly stable in water,
HCl aqueous solution (pH = 1), and NaOH aqueous solution (pH = 10)
at room temperature, as well as in boiling water. Interestingly, the
rational modification of the metal clusters in these MOFs with different
functional groups (HCOO<sup>–</sup>, CH<sub>3</sub>COO<sup>–</sup>, H<sub>2</sub>O/OH, and PhCOO<sup>–</sup>)
enables the precise tuning of their water adsorption properties, which
is quite important for given application. Furthermore, all four MOFs
show excellent regenerability under mild conditions and good cyclic
performance in water adsorption
Tuning Water Sorption in Highly Stable Zr(IV)-Metal–Organic Frameworks through Local Functionalization of Metal Clusters
Water
adsorption of metal–organic frameworks (MOFs) is attracting
intense interest because of their potential applications in atmospheric
water harvesting, dehumidification, and adsorption-based heating and
cooling. In this work, through using a hexacarboxylate ligand, four
new isostructural ZrÂ(IV)-MOFs (BUT-46F, -46A, -46W, and -46B) with
rare low-symmetric 9-connected Zr<sub>6</sub> clusters were synthesized
and structurally characterized. These MOFs are highly stable in water,
HCl aqueous solution (pH = 1), and NaOH aqueous solution (pH = 10)
at room temperature, as well as in boiling water. Interestingly, the
rational modification of the metal clusters in these MOFs with different
functional groups (HCOO<sup>–</sup>, CH<sub>3</sub>COO<sup>–</sup>, H<sub>2</sub>O/OH, and PhCOO<sup>–</sup>)
enables the precise tuning of their water adsorption properties, which
is quite important for given application. Furthermore, all four MOFs
show excellent regenerability under mild conditions and good cyclic
performance in water adsorption
Tuning Water Sorption in Highly Stable Zr(IV)-Metal–Organic Frameworks through Local Functionalization of Metal Clusters
Water
adsorption of metal–organic frameworks (MOFs) is attracting
intense interest because of their potential applications in atmospheric
water harvesting, dehumidification, and adsorption-based heating and
cooling. In this work, through using a hexacarboxylate ligand, four
new isostructural ZrÂ(IV)-MOFs (BUT-46F, -46A, -46W, and -46B) with
rare low-symmetric 9-connected Zr<sub>6</sub> clusters were synthesized
and structurally characterized. These MOFs are highly stable in water,
HCl aqueous solution (pH = 1), and NaOH aqueous solution (pH = 10)
at room temperature, as well as in boiling water. Interestingly, the
rational modification of the metal clusters in these MOFs with different
functional groups (HCOO<sup>–</sup>, CH<sub>3</sub>COO<sup>–</sup>, H<sub>2</sub>O/OH, and PhCOO<sup>–</sup>)
enables the precise tuning of their water adsorption properties, which
is quite important for given application. Furthermore, all four MOFs
show excellent regenerability under mild conditions and good cyclic
performance in water adsorption
Nanocage containing metal-organic framework constructed from a newly designed low symmetry tetra-pyrazole ligand
<p>1368-Tetra(1<i>H</i>-pyrazol-4-yl)-9<i>H</i>-carbazole (H<sub>4</sub>CTP), a tetra-pyrazole ligand with <i>C</i><sub>s</sub> symmetry, has been synthesized based on a carbazole core. A solvothermal reaction of this ligand with NiCl<sub>2</sub>·6H<sub>2</sub>O gave a three-dimensional (3-D) metal-organic framework (MOF), [Ni(H<sub>4</sub>CTP)Cl<sub>2</sub>]·nS (<b>BUT-41</b>), which crystallized in the cubic space group <i>Pm</i>-3 in spite of H<sub>4</sub>CPT with a central carbazole core and four peripheral pyrazole rings has low symmetry. The framework of <b>BUT-41</b> can be regarded as a four-connected 3-D net with the <b><i>rhr</i></b> topology when both the organic ligand and the metal center are considered as four-connected nodes. Nanocages with internal diameter of 2 nm are present in the framework of <b>BUT-41</b>, which are formed by interconnecting 12 H<sub>4</sub>CTP ligands and 20 Ni(II) ions. Each nanocage connects with six adjacent cages through sharing hexagonal windows with diameter over 7 Å, resulting in 3-D intersecting channels of the MOF. Although the tetra-pyrazole ligand is not deprotonated after coordination with the metal ions, powder X-ray diffraction and N<sub>2</sub> adsorption experiments reveal that the framework of <b>BUT-41</b> is rigid and permanently porous with the Brunauer-Emmett-Teller surface area up to 1551 m<sup>2</sup> g<sup>−1</sup>. Furthermore, gas adsorption experiments show that this MOF selectively adsorbs CO<sub>2</sub> over N<sub>2</sub> and CH<sub>4</sub>.</p
A Base-Resistant Metalloporphyrin Metal–Organic Framework for C–H Bond Halogenation
A base-resistant porphyrin metal–organic
framework (MOF),
namely PCN-602 has been constructed with 12-connected [Ni<sub>8</sub>(OH)<sub>4</sub>(H<sub>2</sub>O)<sub>2</sub>Pz<sub>12</sub>] (Pz
= pyrazolate) cluster and a newly designed pyrazolate-based porphyrin
ligand, 5,10,15,20-tetrakisÂ(4-(pyrazolate-4-yl)Âphenyl)Âporphyrin under
the guidance of the reticular synthesis strategy. Besides its robustness
in hydroxide solution, PCN-602 also shows excellent stability in aqueous
solutions of F<sup>–</sup>, CO<sub>3</sub><sup>2–</sup>, and PO<sub>4</sub><sup>3–</sup> ions. Interestingly, the
Mn<sup>3+</sup>-porphyrinic PCN-602, as a recyclable MOF catalyst,
presents high catalytic activity for the C–H bond halogenation
reaction in a basic system, significantly outperforming its homogeneous
counterpart. For the first time, a porphyrinic MOF was thus used as
an efficient catalyst in a basic solution with coordinating anions,
to the best of our knowledge