A design strategy for the construction of 2D heteropore covalent organic frameworks based on the combination of C2v and D3h symmetric building blocks

2018 ◽  
Vol 9 (3) ◽  
pp. 279-283 ◽  
Author(s):  
Cheng Qian ◽  
En-Cheng Liu ◽  
Qiao-Yan Qi ◽  
Kaijia Xu ◽  
Guo-Fang Jiang ◽  
...  
Keyword(s):  
Building Blocks ◽  
Design Strategy ◽  
Covalent Organic Frameworks

A strategy to construct heteropore covalent organic frameworks has been developed based on a desymmetrization design which takes advantage of the combination of C2v and D3h symmetries.

Dibenzochrysene Enables Tightly Controlled Docking and Stabilizes Photoexcited States in Dual-Pore Covalent Organic Frameworks

2019 ◽  
Author(s):  
Torben Sick ◽  
Niklas Keller ◽  
Nicolai Bach ◽  
Andreas Koszalkowski ◽  
Julian Rotter ◽  
...  
Keyword(s):  
Molecular Docking ◽  
Photophysical Properties ◽  
Visible Spectrum ◽  
Large Family ◽  
Building Blocks ◽  
Band Gaps ◽  
Docking Site ◽  
Covalent Organic Frameworks ◽  
Connected Node ◽  
Optoelectronic Applications

Covalent organic frameworks (COFs), consisting of covalently connected organic building units, combine attractive features such as crystallinity, open porosity and widely tunable physical properties. For optoelectronic applications, the incorporation of heteroatoms into a 2D COF has the potential to yield desired photophysical properties such as lower band gaps, but can also cause lateral offsets of adjacent layers. Here, we introduce dibenzo[g,p]chrysene (DBC) as a novel building block for the synthesis of highly crystalline and porous 2D dual-pore COFs showing interesting properties for optoelectronic applications. The newly synthesized terephthalaldehyde (TA), biphenyl (Biph), and thienothiophene (TT) DBC-COFs combine conjugation in the a,b-plane with a tight packing of adjacent layers guided through the molecular DBC node serving a specific docking site for successive layers. The resulting DBC-COFs exhibit a hexagonal dual-pore kagome geometry, which is comparable to COFs containing another molecular docking site, namely 4,4′,4″,4‴-(ethylene-1,1,2,2-tetrayl)-tetraaniline (ETTA). In this context, the respective interlayer distances decrease from about 4.60 Å in ETTA-COFs to about 3.6 Å in DBC-COFs, leading to well-defined hexagonally faceted single crystals sized about 50-100 nm. The TT DBC-COFs feature broad light absorption covering large parts of the visible spectrum, while Biph DBC-COF shows extraordinary excited state lifetimes exceeding 10 ns. In combination with the large number of recently developed linear conjugated building blocks, the new DBC tetra-connected node is expected to enable the synthesis of a large family of strongly p-stacked, highly ordered 2D COFs with promising optoelectronic properties.

Designing the eLTER Research Infrastructure: representativity, priority regions and recommendations for development

2021 ◽  
Author(s):  
Thomas Ohnemus ◽  
Hannes Mollenhauer ◽  
Michael Mirtl ◽  
Steffen Zacharias
Keyword(s):  
Geographical Distribution ◽  
Building Blocks ◽  
Design Strategy ◽  
Critical Zone ◽  
Research Infrastructure ◽  
Statistical Criterion ◽  
Ecological Data ◽  
Continental Scale ◽  
Site Network ◽  
Combining Information

<p>The integrated European Long-Term Ecosystem, critical zone and socio-ecological Research Infrastructure (eLTER RI) was accepted onto the ESFRI roadmap in 2018. While several existing thematic environmental RIs in Europe focus on impacts of climate change and/or other elements of environmental change, eLTER RI will be the only research infrastructure embracing holistically the integrated impacts of such stressors on a wide variety of European benchmark ecosystems (major geo-eco-sociological systems across the continent’s ecoclimatological zones and Earth’s critical zone). In the beginning of 2020 eLTER RI entered the preparatory phase aiming at the development of the legal, financial and technical maturity required for an ESFRI Research Infrastructure.</p><p>The core of the eLTER RI will be ca. 200 selected sites covering all biogeographical zones in Europe, where biological, biogeochemical, hydrological and socio-ecological data will be collected - according to common standards - and analyzed. The European landscape of LTER sites and national networks has mainly been developed in a bottom-up manner. The sites have mostly been established for different monitoring and research purposes and are heterogeneous in terms of investigated ecosystem types, scales of investigation, complexity and instrumentation. Consequently, the transformation of the selected elements of the eLTER RI into a harmonized, high-performance, complementary and interoperable infrastructure is one of the key challenges of eLTER. Achieving the best possible representativity is on the major building blocks in eLTER’s design strategy.</p><p>To evaluate the representativity of eLTER a novel statistical approach combining information on biogeographical, ecological and socio-economic gradients with the management-relevant distribution of established sites was developed aiming at  i) identification of areas in Europe that are geographically underrepresented by the existing eLTER RI site network, ii) definition of priority regions for the geographical extension of the eLTER site network and, iii) development of suggestions for conceptual and infrastructural upgrades for existing less developed eLTER sites.</p><p>Reference datasets depicting biogeographical, ecological and socio-economical gradients were used to describe underrepresentation with a summation parameter called Aggregated Representedness. This statistical criterion was then used to classify five types of “priority regions” from very low to very high priority for geographical and/or conceptual extension. In a second step this information on priority regions was refined using additional information describing the geographical distribution based on Euclidean distances between established eLTER sites.  The combination of these two analyses allowed to identify less developed eLTER sites most suitable for conceptual and infrastructural upgrades. Thus, the presented analysis provides important information for the development of the design strategy for eLTER RI on the continental scale.</p><p>Concluding, a novel approach combining information on biogeographical, ecological and socio-economic gradients with the management-relevant information on the geographical distribution of established sites was developed. This tool allows to evaluate the strategies for further extension of established site networks. </p>

Three-dimensional porphyrin-based covalent organic frameworks with tetrahedral building blocks for single-site catalysis

2019 ◽  
Vol 43 (43) ◽  
pp. 16907-16914 ◽  
Author(s):  
Yong Liu ◽  
Xiaodong Yan ◽  
Tao Li ◽  
Wen-Da Zhang ◽  
Qiu-Ting Fu ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Three Dimensional ◽  
Building Blocks ◽  
Single Site ◽  
Covalent Organic Frameworks ◽  
Excellent Performance ◽  
Biomimetic Catalysis ◽  
Single Site Catalysts

Two 3D porphyrin-based covalent organic frameworks were synthesized as single-site catalysts and exhibited excellent performance in biomimetic catalysis and oxygen evolution reactions.

Twist Building Blocks from Planar to Tetrahedral for the Synthesis of Covalent Organic Frameworks

2020 ◽  
Vol 142 (8) ◽  
pp. 3718-3723 ◽  
Author(s):  
Chao Gao ◽  
Jian Li ◽  
Sheng Yin ◽  
Junliang Sun ◽  
Cheng Wang
Keyword(s):  
Building Blocks ◽  
Covalent Organic Frameworks

scholarly journals Design of Mechanically Flexible Organic Crystals: A Crystal Engineering Approach

2014 ◽  
Vol 70 (a1) ◽  
pp. C648-C648
Author(s):  
Gamidi Krishna ◽  
Ramesh Devarapalli ◽  
Garima Lal ◽  
C. Reddy
Keyword(s):  
Crystal Structures ◽  
Organic Solar Cells ◽  
Crystal Engineering ◽  
Rational Design ◽  
Organic Materials ◽  
Building Blocks ◽  
Design Strategy ◽  
High Plasticity ◽  
Simple Strategy ◽  
Slip Planes

Utilization of organic single crystal materials is increasing day by day owing to their promising applications in organic light emitting diodes [1], organic solar cells, mechanochromic luminescence [2] and tablatability [3] of APIs etc. These desirable functions, especially mechanical properties, can be achieved by imparting soft nature in organic materials, however unfortunately there is no simple strategy to attain this. Till date all the findings are serendipitous discoveries, so a rational design strategy is necessary to accomplish such soft mechanical behavior in molecular crystals. Here we propose a design strategy to attain plastically deformable organic materials by introducing slip planes in the crystal structures. The high plasticity can be achieved by introducing hydrophobic groups, such as t-Bu, -OMe, -Me and multiple –Cl (or) –Br groups on -Ar building blocks, for example on naphthalene diimide (NDI), which leads to the formation of slip planes in the crystal structures (as shown in attached figure), hence facilitate the plastic (irreversible) bending [2].

scholarly journals Chiral covalent organic frameworks: design, synthesis and property

2020 ◽  
Author(s):  
X Han ◽  
C Yuan ◽  
B Hou ◽  
Lujia Liu ◽  
H Li ◽  
...  
Keyword(s):  
Porous Materials ◽  
Asymmetric Catalysis ◽  
Chiral Recognition ◽  
Building Blocks ◽  
Enantioselective Separation ◽  
Structural Studies ◽  
Covalent Organic Frameworks ◽  
Covalent Bonds ◽  
Design Synthesis ◽  
Potential Applications

Covalent organic frameworks (COFs) are constructed using reticular chemistry with the building blocks being connected via covalent bonds and have emerged as a new series of porous materials for multitudinous applications. Most COFs reported to date are achiral, and only a small fraction of COFs with chiral nature are reported. This review covers the recent advances in the field of chiral COFs (CCOFs), including their design principles and synthetic strategies, structural studies, and potential applications in asymmetric catalysis, enantioselective separation, and chiral recognition. Finally, we illustrate the remaining challenges and future opportunities in this field.

scholarly journals A design strategy to match the band gap of periodic and aperiodic metamaterials

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Luca D’Alessandro ◽  
Anastasiia O. Krushynska ◽  
Raffaele Ardito ◽  
Nicola M. Pugno ◽  
Alberto Corigliano
Keyword(s):  
Mechanical Property ◽  
Band Gap ◽  
Experimental Tests ◽  
Building Blocks ◽  
Design Strategy ◽  
Theoretical Explanation ◽  
Wavelength Band ◽  
Elastic Metamaterials ◽  
Periodic Repetition ◽  
Sub Wavelength

Abstract The focus of this paper is on elastic metamaterials characterised by the presence of wide sub-wavelength band gap. In most cases, such mechanical property is strictly connected to the periodic repetition of the unit cell. Nonetheless, the strict periodicity requirement could represent a drawback. In this paper, we present a design strategy for aperiodic elastic metamaterials in order to achieve the same performances as for the periodic counterparts. This is done by exploiting the concept of separation of modes for different building blocks, arranged in aperiodic fashion. A theoretical explanation is provided, as well as numerical simulations; the concept is validated by means of a set of experimental tests on prototypes that are realized via additive manufacturing.

scholarly journals Chiral covalent organic frameworks: design, synthesis and property

2020 ◽  
Author(s):  
X Han ◽  
C Yuan ◽  
B Hou ◽  
Lujia Liu ◽  
H Li ◽  
...  
Keyword(s):  
Porous Materials ◽  
Asymmetric Catalysis ◽  
Chiral Recognition ◽  
Building Blocks ◽  
Enantioselective Separation ◽  
Structural Studies ◽  
Covalent Organic Frameworks ◽  
Covalent Bonds ◽  
Design Synthesis ◽  
Potential Applications

Covalent organic frameworks (COFs) are constructed using reticular chemistry with the building blocks being connected via covalent bonds and have emerged as a new series of porous materials for multitudinous applications. Most COFs reported to date are achiral, and only a small fraction of COFs with chiral nature are reported. This review covers the recent advances in the field of chiral COFs (CCOFs), including their design principles and synthetic strategies, structural studies, and potential applications in asymmetric catalysis, enantioselective separation, and chiral recognition. Finally, we illustrate the remaining challenges and future opportunities in this field.

A supramolecular strategy based on molecular dipole moments for high-quality covalent organic frameworks

2016 ◽  
Vol 52 (51) ◽  
pp. 7986-7989 ◽  
Author(s):  
Laura M. Salonen ◽  
Dana D. Medina ◽  
Enrique Carbó-Argibay ◽  
Maarten G. Goesten ◽  
Luís Mafra ◽  
...  
Keyword(s):  
Surface Area ◽  
Intermolecular Interactions ◽  
Dipole Moments ◽  
Building Blocks ◽  
Large Surface Area ◽  
Covalent Organic Frameworks ◽  
High Quality ◽  
Molecular Dipole ◽  
High Crystallinity ◽  
Strong Dipole

Attractive intermolecular interactions of building blocks with strong dipole moments result in a COF with high crystallinity and large surface area.

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