A Homochiral Microporous Hydrogen-Bonded Organic Framework for Highly Enantioselective Separation of Secondary Alcohols

A homochiral microporous hydrogen-bonded organic framework (HOF-2) based on a BINOL derivative has been synthesized and structurally characterized to be a uninodal 6-connected {3³5⁵6⁶7} network. This new HOF exhibits not only a permanent porosity with the BET of 237.6 m² g^–1 but also, more importantly, a highly enantioselective separation of chiral secondary alcohols with ee value up to 92% for 1-phenylethanol

A Homochiral Microporous Hydrogen-Bonded Organic Framework for Highly Enantioselective Separation of Secondary Alcohols

A homochiral microporous hydrogen-bonded organic framework (HOF-2) based on a BINOL derivative has been synthesized and structurally characterized to be a uninodal 6-connected {3³5⁵6⁶7} network. This new HOF exhibits not only a permanent porosity with the BET of 237.6 m² g^–1 but also, more importantly, a highly enantioselective separation of chiral secondary alcohols with ee value up to 92% for 1-phenylethanol

Mixed-Valence Cobalt(II/III) Metal–Organic Framework for Ammonia Sensing with Naked-Eye Color Switching

The construction of colorimetric sensing materials with high selectivity, low detection limits, and great stability provides a significant way for facile device implementation of an ammonia (NH₃) sensor. Herein, with excellent alkaline stability and exposed N sites in molecule as well as with naked-eye color switching nature generated from changeable cobalt (Co) valence, a three-dimensional mixed-valence cobalt­(II/III) metal–organic framework (<b>FJU-56</b>) with tris-(4-tetrazolyl-phenyl)­amine (H₃L) ligand was synthesized for colorimetric sensing toward ammonia. The activated <b>FJU-56</b> demonstrates a limit of detection of 1.38 ppm for ammonia sensing, with high selectivity in ammonia and water competitive adsorption, and shows outstanding stability and reversibility in the cyclic test. The NH₃ or water molecules binding to the exposed N sites with the hydrogen-bond are observed by single-crystal X-ray diffraction, determining that the attachment of guest molecules to the <b>FJU-56</b> framework changes the valence of Co ions with a naked-eye color switching response, which provides an ocular demonstration for ammonia capture and a valuable insight into ammonia sensing

Rhodium-Catalyzed NH-Indole-Directed C–H Carbonylation with Carbon Monoxide: Synthesis of 6<i>H</i>‑Isoindolo[2,1‑<i>a</i>]indol-6-ones

An efficient synthesis of 6<i>H</i>-isoindolo­[2,1-<i>a</i>]­indol-6-ones through rhodium-catalyzed NH-indole-directed C–H carbonylation of 2-arylindoles with carbon monoxide has been developed. Preliminary mechanistic studies revealed that this reaction proceeds via N–H bond cleavage and subsequent C–H bond cleavage. Reaction monitoring via ESI-MS was used to support the formation of five-membered rhodacycle species in the catalytic cycle

Mixed-Valence Cobalt(II/III) Metal–Organic Framework for Ammonia Sensing with Naked-Eye Color Switching

The construction of colorimetric sensing materials with high selectivity, low detection limits, and great stability provides a significant way for facile device implementation of an ammonia (NH₃) sensor. Herein, with excellent alkaline stability and exposed N sites in molecule as well as with naked-eye color switching nature generated from changeable cobalt (Co) valence, a three-dimensional mixed-valence cobalt­(II/III) metal–organic framework (<b>FJU-56</b>) with tris-(4-tetrazolyl-phenyl)­amine (H₃L) ligand was synthesized for colorimetric sensing toward ammonia. The activated <b>FJU-56</b> demonstrates a limit of detection of 1.38 ppm for ammonia sensing, with high selectivity in ammonia and water competitive adsorption, and shows outstanding stability and reversibility in the cyclic test. The NH₃ or water molecules binding to the exposed N sites with the hydrogen-bond are observed by single-crystal X-ray diffraction, determining that the attachment of guest molecules to the <b>FJU-56</b> framework changes the valence of Co ions with a naked-eye color switching response, which provides an ocular demonstration for ammonia capture and a valuable insight into ammonia sensing

A Homochiral Microporous Hydrogen-Bonded Organic Framework for Highly Enantioselective Separation of Secondary Alcohols

A homochiral microporous hydrogen-bonded organic framework (HOF-2) based on a BINOL derivative has been synthesized and structurally characterized to be a uninodal 6-connected {3³5⁵6⁶7} network. This new HOF exhibits not only a permanent porosity with the BET of 237.6 m² g^–1 but also, more importantly, a highly enantioselective separation of chiral secondary alcohols with ee value up to 92% for 1-phenylethanol

A Homochiral Microporous Hydrogen-Bonded Organic Framework for Highly Enantioselective Separation of Secondary Alcohols

A homochiral microporous hydrogen-bonded organic framework (HOF-2) based on a BINOL derivative has been synthesized and structurally characterized to be a uninodal 6-connected {3³5⁵6⁶7} network. This new HOF exhibits not only a permanent porosity with the BET of 237.6 m² g^–1 but also, more importantly, a highly enantioselective separation of chiral secondary alcohols with ee value up to 92% for 1-phenylethanol

Highly Selective Adsorption of C₂/C₁ Mixtures and Solvent-Dependent Thermochromic Properties in Metal–Organic Frameworks Containing Infinite Copper-Halogen Chains

Separation of light hydrocarbon mixtures is a very important but challenging industrial separation task. Here, we have synthesized two isostructural cationic metal–organic frameworks {[(Cu­(Btz)­X]·X·6H₂O·0.25DMSO} (<b>FJU-53</b>, Btz = 1,4′-Bis­(4<i>H</i>-1,2,4-triazol-4-yl)­benzene, X = Cl or Br, DMSO = dimethyl sulfoxide) containing infinite copper-halogen chains and first demonstrated that the adsorption selectivity toward C₂/C₁ mixtures in the charged MOFs can be improved by tuning counter-anions. <b>FJU-53</b> exhibits the highest selectivity for C₂H₂/CH₄ separation at 296 K and 1 atm, and exceptional chemical stability in aqueous solutions with pH ranging from 1 to 13. In addition, <b>FJU-53</b> also shows the attractive solvent- and halogen-dependent thermochromic behaviors. Its thermochromic mechanism is attributed to the thermally induced vibration of the infinite [(CuX)_<i>n</i>]^<i>n</i>+ chains, remarkably different from that for the traditional copper­(II) halide materials, the thermochromism for which comes from the coordination geometry transformation or Jahn–Teller distortion

A Flexible Microporous Hydrogen-Bonded Organic Framework for Gas Sorption and Separation

A microporous three-dimensional hydrogen-bonded organic framework (HOF-5) has been constructed from a new organic linker 4,4′,4″,4‴-tetra­(2,4-diamino-1,3,5-triazin-6-yl)­tetraphenylethene. Activated HOF-5a exhibits a stepwise N₂ adsorption isotherm at 77 K, suggesting framework flexibility. The structure of activated HOF-5a has been established by powder X-ray diffraction studies, indicating a significant framework contraction from as-synthesized HOF-5 to activated HOF-5a of ∼21% by volume. HOF-5a shows moderately high porosity with a Brunauer–Emmett–Teller (BET) surface area of 1101 m²/g, and takes up a large amount of acetylene and carbon dioxide under ambient conditions. Powder neutron diffraction studies and theoretical calculations reveal that suitable pore sizes, curvatures, and functional sites collectively enable HOF-5a to encapsulate a high density of carbon dioxide molecules packed in a pseudo-one-dimensional array along the pore channel

Novel Microporous Metal–Organic Framework Exhibiting High Acetylene and Methane Storage Capacities

A new organic hexacarboxylic acid, 5,5′,5″-(9<i>H</i>-carbazole-3,6,9-triyl)­triisophthalic acid (H₆CTIA), was developed to construct its first microporous metal–organic framework (MOF), Cu₆(CTIA)₂ (ZJU-70). With open metal sites and suitable pore sizes, this MOF exhibits high acetylene and methane storage capacities at room temperature