Stable, Dual Redox Unit Organic Electrodes

The development of organic materials for electrochemical energy storage has attracted great attention because of their high natural abundance and relatively low toxicity. The bulk of these studies focus on small molecules, polymers, or porous/framework-type materials that employ one type of redox moiety. Here, we report the synthesis and testing of organic materials that incorporate two distinct types of redox units: triptycene-based quinones and perylene diimides. We examine this "dual redox" concept through the synthesis of both frameworks and small molecule model compounds with the redox units positioned at the vertices and connection points. Such a design increases the theoretical capacity of the material. It also imparts high stability because both examples are relatively rigid and highly insoluble in the electrolyte. Lithium-ion batteries consisting of the framework and the small molecule have an excellent cycling retention of 75 and 77%, respectively, over 500 cycles at 1 C. Our work emphasizes the advantages of using multiple redox units in the design of the cathodic materials and redox-active triptycene linkages to achieve high cycling stability.

Temperature-induced structural diversity of metal-organic frameworks and their applications in selective sensing of nitrobenzene and electrocatalyzing the oxygen evolution reaction

Structural diversities are presented in four new Co-MOFs containing 1,5-bi(imidazolyl)anthracene and different dibenzobarrelene skeletons based on dicarboxylic acid, in which MOFs 1-3 exhibit 2D networks in a 4-connected node sql topology with the point symbol of {44·62}, while MOF 4 forms a 1D chain structure. It is clearly observed that the 2D-1D structural transformation of 2-4 has been realized by temperature modulated hydrothermal synthesis procedures from 120-160 °C, suggesting the key role of temperature for constructing MOFs. In addition, obvious π-π interactions between anthracene rings can be observed in the architectures of 1-3, which may favorably stabilize their 2D supramolecular networks. More importantly, fluorescence behaviors of 1-4 have been investigated in water among various nitro-aromatic compounds (NACs) and the results show that all samples exhibit high selectivity and fine sensitivity to nitrobenzene (NB) with fluorescence quenching, which is confirmed to be the result of electron transfer from the excited state of ligands to that of NB by density functional theory. Furthermore, MOFs 1-4 have been directly employed as electrocatalysts for the oxygen evolution reaction (OER), in which MOF 4 gives the best activity towards the OER among all as-synthesized samples with an overpotential of 398 mV at a current density of 10 mA cm-2 and a low Tafel slope of 59 mV dec-1.

Optically active triptycenes containing hexa-peri-hexabenzocoronene units

We have successfully generated both left- and right-handed circularly polarized light using crystals prepared from a racemic triptycene containing hexa-peri-hexabenzocoronene units.

Circularly Polarized Luminescent Triptycene-Based Polymers

A series of chiral fluorescent polymers containing optically active triptycene units in the main chain were synthesized via Sonogashira-Hagihara coupling copolymerizations of (R,R)- or (S,S)-2,6-diethynyltriptycene with a range of diiodoaryls. Their optical and chiroptical properties were investigated under various solution conditions. We observe that these polymers emitted circularly polarized light owing to the chiral triptycene framework with a handed twisted rigid structure, and the fluorescence colors could be tuned in the whole visible range from blue to red by replacing the achiral comonomer units. They possessed luminescence dissymmetry factors of approximately 1.0 × 10^-3, regardless of the incorporated comonomer units.

A 2D porous pentiptycene-based MOF for efficient detection of Ba2+ and selective adsorption of dyes from water

The 2D MOF (UPC-28) as the water monitor can exhibit efficient detection of Ba²⁺ and perform selective adsorption of dyes from water.

High-Yielding and Divergent Paradigm for the Synthesis of D2h-Symmetric Octakis-Substituted Pentiptycenequinones

With a rigid fused polyaromatic framework and a well-defined, highly symmetric molecular geometry, pentiptycenes are appealing building blocks for a variety of materials applications. Unfortunately, their use has been limited by the lengthy syntheses of their functionalized derivatives. This communication describes a highly efficient, brief, divergent paradigm for the preparation of octakis-substituted pentiptycene derivatives that starts with the preparation of an octakis(bromo) compound, which can be used as a Pd(0)-catalyzed coupling partner with suitable organometallic compounds to install a range of groups in high yields at the peripheral 2,3,6,7,14,15,19,20 positions, including methyl, allyl, vinyl, alkynyl, aryl, heteroaryl, and even bulky 4-(triphenylmethyl)phenyl substituents.

Chiral triptycene-pyrene π-conjugated chromophores with circularly polarized luminescence

Novel chiral triptycenes showing circularly polarized luminescence based on the supramolecular chirality induced in the hydrogen-bonded aggregate have been developed.

Supramolecular coordination polymers using a close to ‘V-shaped’ fluorescent 4-amino-1,8-naphthalimide Tröger's base scaffold

A novel 4-amino-1,8-naphthalimide derived Tröger's base ligand L has been synthesised and subsequently used in the formation of two new supramolecular coordination polymers TB-Co-CP and TB-Cd-CP.

Pentiptycene-Based Luminescent Cu (II) MOF Exhibiting Selective Gas Adsorption and Unprecedentedly High-Sensitivity Detection of Nitroaromatic Compounds (NACs)

The assembly of a fluorescent pentiptycene-based ligand with copper ion resulted in the formation of a 3D porous metal-organic framework (UPC-21) based on well-known paddlewheel SBUs. UPC-21 exhibits selective adsorption of CO2 over CH4 and N2 at 273 K and 295 K, C2H2 over CH4 at 273 K. The most significant performance of UPC-21 is its highly efficient detection of NACs such as 4-NP, 1,4-DNB, NB, and 1,3-DNB with the calculated quenching constants, Ksv, being 3.097 × 10(6), 1.406 × 10(6), 4.420 × 10(5), and 1.498 × 10(5 )M(-1) for 4-NP, 1,4-DNB, NB, 1,3-DNB, respectively, which keeps a record on the fluorescence detection of NACs. This is the first porous Cu(II) MOF that exhibits fluorescent detection of NACs with high sensitivities.

Preparation of raspberry-like ZIF-8/PS composite spheres via dispersion polymerization

A facile method for the preparation of raspberry-like ZIF-8/PS organic–inorganic composite spheres through dispersion polymerization.

Structural diversification and photocatalytic properties of zinc(ii) polymers modified by auxiliary N-containing ligands

Four zinc coordination polymers with different architectures based on 5-(1H-benzoimidazol-2-ylsulfanylmethyl)-isophthalic acid have been prepared. Their photoluminescence and photocatalytic properties were also investigated.