The true liquid crystal phases of 2D polymeric carbon nitride and macroscopic assembled fibers

<a></a><a>As a metal-free conjugated polymer, carbon nitride (CN) has attracted tremendous attention as heterogeneous (photo)catalysts. </a><a></a><a>By following prototype of enzymes, making all catalytic sites of accessible via homogeneous reactions is a promising approach toward maximizing CN activity, but hindered due to </a><a></a><a>the poor insolubility of CN</a>. Herein, we report the dissolution of CN in environment-friendly methane sulfonic acid and the homogeneous photocatalysis driven by CN for the first time with the activity boosted up to 10-times, comparing to the heterogeneous counterparts. Moreover, facile recycling and reusability, the <a>hallmark</a> of heterogeneous catalysts, were kept for the homogeneous CN photocatalyst via reversible precipitation using poor solvents. It opens new vista of CN in homogeneous catalysis and offers a successful example of polymeric catalysts in bridging gaps of homo/heterogeneous catalysis.

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Cubic and tetragonal liquid crystal phases composed of non-chiral molecules: Chirality and macroscopic properties

The European Physical Journal E ◽

10.1140/epje/i2019-11906-8 ◽

2019 ◽

Vol 42 (11) ◽

Cited By ~ 6

Author(s):

Helmut R. Brand ◽

Harald Pleiner

Keyword(s):

Liquid Crystal ◽

Liquid Crystalline ◽

Triblock Copolymers ◽

Similar Type ◽

Chiral Molecules ◽

Chiral Compounds ◽

Liquid Crystalline Phases ◽

Symmetry Properties ◽

Crystal Phases ◽

Liquid Crystal Phases

Abstract. We discuss the symmetry properties as well as the macroscopic behavior of the cubic liquid crystal phases showing large chiral domains of either hand in some non-chiral compounds reported recently in the group of Tschierske. These phases are tricontinuous. While they have O or I432 symmetry in each chiral domain, the overall symmetry is $ I m \bar{3} m$Im3¯m as there is no net chirality for compounds composed of non-chiral molecules. It turns out that a rather similar type of phase has also been reported for triblock copolymers. Here we analyze in detail the macroscopic static and dynamic behavior of such phases and we predict, among other results, that they show the analog of static and dissipative Lehmann-type effects in their chiral domains. A description of a cubic liquid crystalline phase of Th symmetry, which has not yet been found experimentally, is also included. Suggestions for experiments are outlined to identify such a phase. In addition, we discuss tetragonal liquid crystalline phases of D4h and D4 (I422) symmetry as they have been reported last year experimentally in connection to the Q phase. Graphical abstract

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NIR-Responsive Carbon Nitride of Five-Membered Rings (C3N2) for Photoelectrochemical Biosensing

10.26434/chemrxiv.12195429.v1 ◽

2020 ◽

Author(s):

Hong Yang ◽

Qing Zhou ◽

Zhengzou Fang ◽

Lufang Zhao ◽

Jin Ma ◽

...

Keyword(s):

Density Functional ◽

Carbon Nitride ◽

Density Functional Theory Calculations ◽

Electronic Band ◽

Functional Theory ◽

Hard Materials ◽

Polymeric Carbon ◽

First Time ◽

Electronic Transition Energy

Polymeric carbon nitrides (pCN) have garnered immense attention, ranging from super-hard materials to artificial photosynthesis, due to their exceptional chemical and optoelectronic properties. The most studied C3N4 along with other stoichiometric pCN, such as C3N, C2N and C3N5, commonly employed a six-membered ring as the basic units; while the five-membered rings are also popular in a myriad of natural and artificial molecules with a more polarized framework and intriguing functionalities. Here, we report a facile synthesis of C3N2 with a topological structure of five-membered rings, endowing by far the narrowest the first electronic transition energy (0.81 eV) in pCN family. The basic imidazole unit with dangling bonds, resulting in an unusual electronic band of p-π conjugation and split molecular orbitals, was revealed in C3N2 by both experiments and density functional theory calculations. Moreover, a NIR-responsive photoelectrochemical (PEC) biosensor for non-transparent biosamples was constructed for the first time using C3N2 with outstanding performance. This work would not only open a new vista of pCN with different topological structures but also broaden the horizon of their application, such as prospective in vivo PEC bioassay.

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NIR-Responsive Carbon Nitride of Five-Membered Rings (C3N2) for Photoelectrochemical Biosensing

10.26434/chemrxiv.12195429 ◽

2020 ◽

Author(s):

Hong Yang ◽

Qing Zhou ◽

Zhengzou Fang ◽

Lufang Zhao ◽

Jin Ma ◽

...

Keyword(s):

Density Functional ◽

Carbon Nitride ◽

Density Functional Theory Calculations ◽

Electronic Band ◽

Functional Theory ◽

Hard Materials ◽

Polymeric Carbon ◽

First Time ◽

Electronic Transition Energy

Polymeric carbon nitrides (pCN) have garnered immense attention, ranging from super-hard materials to artificial photosynthesis, due to their exceptional chemical and optoelectronic properties. The most studied C3N4 along with other stoichiometric pCN, such as C3N, C2N and C3N5, commonly employed a six-membered ring as the basic units; while the five-membered rings are also popular in a myriad of natural and artificial molecules with a more polarized framework and intriguing functionalities. Here, we report a facile synthesis of C3N2 with a topological structure of five-membered rings, endowing by far the narrowest the first electronic transition energy (0.81 eV) in pCN family. The basic imidazole unit with dangling bonds, resulting in an unusual electronic band of p-π conjugation and split molecular orbitals, was revealed in C3N2 by both experiments and density functional theory calculations. Moreover, a NIR-responsive photoelectrochemical (PEC) biosensor for non-transparent biosamples was constructed for the first time using C3N2 with outstanding performance. This work would not only open a new vista of pCN with different topological structures but also broaden the horizon of their application, such as prospective in vivo PEC bioassay.

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Semiconducting and electropolymerizable liquid crystalline carbazole-containing porphyrin-core dendrimers

Organic Chemistry Frontiers ◽

10.1039/d0qo00537a ◽

2020 ◽

Vol 7 (15) ◽

pp. 2008-2015 ◽

Cited By ~ 2

Author(s):

Alberto Concellón ◽

Roberto Termine ◽

Attilio Golemme ◽

Pilar Romero ◽

Mercedes Marcos ◽

...

Keyword(s):

Liquid Crystal ◽

Nematic Liquid Crystal ◽

Liquid Crystalline ◽

Porphyrin Core ◽

Crystal Phases ◽

Liquid Crystal Phases

We have successfully synthesized porphyrin-core dendrimers with peripheral carbazole moieties, which can be electrochemically crosslinked. Moreover, these dendrimers exhibit discotic nematic liquid crystal phases with high hole mobilities.

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Facile Synthesis of 3-(Azol-1-yl)-1-adamantanecarboxylic Acids—New Bifunctional Angle-Shaped Building Blocks for Coordination Polymers

Molecules ◽

10.3390/molecules24152717 ◽

2019 ◽

Vol 24 (15) ◽

pp. 2717 ◽

Cited By ~ 5

Author(s):

Dmitry Pavlov ◽

Taisiya Sukhikh ◽

Evgeny Filatov ◽

Andrei Potapov

Keyword(s):

Sulfuric Acid ◽

Carboxylic Acid ◽

Coordination Polymers ◽

Building Blocks ◽

X Ray Diffraction ◽

Facile Synthesis ◽

X Ray ◽

Adamantanecarboxylic Acid ◽

Concentrated Sulfuric Acid ◽

First Time

For the first time, orthogonally substituted azole-carboxylate adamantane ligands were synthesized and used for preparation of coordination polymers. The angle-shaped ligands were prepared by the reaction of 1-adamantanecarboxylic acid and azoles (1H-1,2,4-triazole, 3-methyl-1H-1,2,4-triazole, 3,5-dimethyl-1H-1,2,4-triazole, 1H-tetrazole, 5-methyl-1H-tetrazole) in concentrated sulfuric acid. Variation of the solvent and substituents in azole rings allowed to prepare both 1D and 2D copper(II) and nickel(II) coordination polymers, [Cu2(trzadc)4(H2O)0.7]∙DMF∙0.3H2O, [Cu(trzadc)2(MeOH)]∙MeOH, [Ni(trzadc)2(MeOH)2] and [Cu2(mtrzadc)3(MeOH)]+NO3– (trzadc-3-(1,2,4-triazol-1-yl)-adamantane-1-carboxylic acid; mtrzadc-3-(3-methyl-1,2,4-triazol-1-yl)-adamantane-1-carboxylic acid) which were structurally characterized by single crystal X-ray diffraction. Complex [Cu(trzadc)2(MeOH)]∙MeOH was shown to act as a catalyst in the Chan-Evans-Lam arylation reaction.

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Phase Behavior Studies on ZnS Nanoparticles Doped Liquid Crystal Mixture

Zeitschrift für Physikalische Chemie ◽

10.1515/zpch-2016-0757 ◽

2016 ◽

Vol 230 (10) ◽

Cited By ~ 1

Author(s):

Marimuthu Santhosh ◽

Thangaiyan Chitravel ◽

Ramasamy Jayaprakasam ◽

Vellalapalayam Nallagounder Vijayakumar

Keyword(s):

Liquid Crystal ◽

Liquid Crystalline ◽

Optical Microscope ◽

Stability Factor ◽

Zns Nanoparticles ◽

Chiral Compound ◽

Cholesteric Phase ◽

Blue Phase ◽

Crystal Phases ◽

Span Width

AbstractThe Liquid Crystalline (LC) mixture is prepared from chiral compound of cholesteryl nonanoate and non-chiral compound of biphenylpyrimidine. The phase change with temperature and corresponding textures of the LC mixtures are analyzed by Polarizing Optical Microscope (POM). LC mixture at its isotropic state is doped with 1% of ZnS nanoparticles and its influence on mesophases is discussed. Normally blue phase is identified within narrow thermal width. The note worthy observation is that the blue phase and cholesteric phase with extended thermal span width in the ZnS doped LC mixture. Also the thermal stability factor of the different liquid crystal phases is discussed.

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Luminescence modulation in liquid crystalline phases containing a dispiro[fluorene-9,11′-indeno[1,2-b]fluorene-12′,9′′-fluorene] core

Journal of Materials Chemistry C ◽

10.1039/c4tc00038b ◽

2014 ◽

Vol 2 (21) ◽

pp. 4265-4275 ◽

Cited By ~ 11

Author(s):

Sébastien Thiery ◽

Benoît Heinrich ◽

Bertrand Donnio ◽

Cyril Poriel ◽

Franck Camerel

Keyword(s):

Liquid Crystal ◽

Liquid Crystalline ◽

Crystalline Phases ◽

Thermotropic Liquid Crystal ◽

Liquid Crystalline Phases ◽

Crystal Phases ◽

Liquid Crystal Phases

Luminescence modulations of a bulky dispiro[fluorene-9,11′-indeno[1,2-b]fluorene-12′,9′′-fluorene] (DSF-IF) core embedded in thermotropic liquid crystal phases.

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Water-Soluble Polymeric Carbon Nitride Colloidal Nanoparticles for Highly Selective Quasi-Homogeneous Photocatalysis

10.26434/chemrxiv.9879947.v1 ◽

2019 ◽

Author(s):

Igor Krivtsov ◽

Dariusz Mitoraj ◽

Marina Ilkaeva ◽

Mariana Sardo ◽

Luís Mafra ◽

...

Keyword(s):

Active Sites ◽

Carbon Nitride ◽

Water Soluble ◽

Colloidal Nanoparticles ◽

Narrow Size Distribution ◽

New Paradigm ◽

Redox Transformations ◽

Homogeneous Photocatalysis ◽

Polymeric Carbon ◽

First Time

Heptazine-based polymeric carbon nitrides (PCN) are well established as promising photocatalysts for light-driven redox transformations. However, the activity of these materials is hampered by their low surface area translating into low concentration of active sites accessible for reactants. Herein, we report, for the first time, a bottom-up preparation of PCN nanoparticles with a narrow size distribution (~10±3 nm), which are fully soluble in water showing no gelation or precipitation over several months, and allow carrying out photocatalysis under quasi-homogeneous conditions. The rate of selective (up to 100%) photooxidation of 4-methoxybenzyl alcohol to 4-methoxybenzaldehyde was enhanced by the factor of 6.5 as compared to conventional solid PCN and was accompanied by simultaneous H2O2 production via reduction of oxygen. The dissolved photocatalyst can be easily recovered and re-dissolved by simple modulation of the ionic strength of the medium, without any loss of activity and selectivity. This work thus establishes a new paradigm of easily operable quasi-homogeneous photocatalysis with PCN, and opens up a route for other applications in which liquid aqueous operation or processing of PCN is required.

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