Use of modulators and light to control crystallisation of a hydrogen bonded framework

2022 ◽  
Author(s):  
Phonlakrit Muang-Non ◽  
Hamish D. Toop ◽  
Christian J. Doonan ◽  
Nicholas G. White
Keyword(s):  
Crystal Size ◽  
Hydrogen Bonded

Modulators, light and solvent are used to control the crystal size of a hydrogen bonded framework.

Investigation of irradiation-induced nucleation processes in silicon and germanium

1995 ◽  
Vol 53 ◽  
pp. 224-225
Author(s):  
Harry A. Atwater ◽  
C.M. Yang ◽  
K.V. Shcheglov
Keyword(s):  
Room Temperature ◽  
Crystal Size ◽  
Initial Distribution ◽  
Engineering Control ◽  
Size Evolution ◽  
Silicon And Germanium ◽  
Ge Quantum Dot ◽  
And Control ◽  
Germanium Quantum Dots ◽  
Kinetics Of

Studies of the initial stages of nucleation of silicon and germanium have yielded insights that point the way to achievement of engineering control over crystal size evolution at the nanometer scale. In addition to their importance in understanding fundamental issues in nucleation, these studies are relevant to efforts to (i) control the size distributions of silicon and germanium “quantum dots𠇍, which will in turn enable control of the optical properties of these materials, (ii) and control the kinetics of crystallization of amorphous silicon and germanium films on amorphous insulating substrates so as to, e.g., produce crystalline grains of essentially arbitrary size.Ge quantum dot nanocrystals with average sizes between 2 nm and 9 nm were formed by room temperature ion implantation into SiO2, followed by precipitation during thermal anneals at temperatures between 30°C and 1200°C[1]. Surprisingly, it was found that Ge nanocrystal nucleation occurs at room temperature as shown in Fig. 1, and that subsequent microstructural evolution occurred via coarsening of the initial distribution.

An Unnatural Amino Acid that Mimics a Tripeptide β-Strand and Forms β-Sheetlike Hydrogen-Bonded Dimers [J. Am. Chem. Soc.2000,122, 7654-7661]. 

2001 ◽  
Vol 123 (7) ◽  
pp. 1545-1546
Author(s):  
James S. Nowick ◽  
De Michael Chung ◽  
Kalyani Maitra ◽  
Santanu Maitra ◽  
Kimberly D. Stigers ◽  
...  
Keyword(s):  
Amino Acid ◽  
Unnatural Amino Acid ◽  
Hydrogen Bonded

Pengaruh Pendopingan Karbon Terhadap Struktur Kristal dan Morfologi TIO2

2019 ◽  
Vol 2 (2) ◽  
Author(s):  
Frastica Deswardani ◽  
Helga Dwi Fahyuan ◽  
Rimawanto Gultom ◽  
Eif Sparzinanda
Keyword(s):  
Thin Film ◽  
Crystal Structure ◽  
Grain Size ◽  
Tio2 Thin Film ◽  
Crystal Size ◽  
Diffraction Peak ◽  
Carbon Doping ◽  
Tio2 Anatase ◽  
Spray Method ◽  
Carbon Analysis

Telah dilakukan penelitian mengenai pengaruh konsentrasi doping karbon pada lapisan tipis TiO2 yang ditumbuhkan dengan metode spray terhadap struktur kristal dan morfologi TiO2. Hasil karakterisasi SEM menunjukkan bahwa penambahan doping karbon dapat meningkatkan ukuran butir. Lapisan TiO2 doping karbon 8% diperoleh ukuran butir terbesar adalah 1.35 μm, sedangkan ukuran tekecilnya adalah 0.45 μm. Sementara itu, untuk lapisan tipis TiO2 didoping karbon 15% memiliki ukuran butir terbesar yaitu 1.76 μm dan terkecil 0.9 μm. Hasil XRD menunjukkan seluruh puncak difraksi lapisan tipis TiO2 dengan doping karbon 8% dan 15% merupakan TiO2 anatase. Ukuran kristal lapisan TiO2 didoping karbon 8% diperoleh sebesar 638,08 Å dan untuk pendopingan 15% karbon ukuran kristal lapisan tipis TiO2 adalah 638,09 Å, hal ini menunjukkan ukuran kristal kedua sampel tidak mengalami perubahan yang signifikan.   TiO2 thin film with carbon doping has been successfully grown by spray method. The research on the effect of carbon doping on crystal structure and morfology of TiO2 has been prepared by varying carbon concentration (8% and 15% carbon). Analysis of SEM showed that the addition of carbon may increase the grain size. Thin film of TiO2 doped carbon 8% has the largest grain size 1.35 μm, while the smallest grain size is 0.45 μm. Meanwhile, for thin film TiO2 doped carbon 15% has the largest grain size 1.76 μm and smallest 0.9 μm. The XRD results showed the entire diffraction peak of thin film TiO2 doped carbon 8% and 15% were TiO2 anatase. The crystal size of thin film TiO2 doped carbon 8% was obtained at 638.08 Å and for thin film TiO2 doped carbon 15% the crystalline size of TiO2 thin film was 638.09 Å, this shows that the crystal size of both samples did not change significantly.    

Hydrogen-Bonded Solvent Systems

1969 ◽  
Vol 67 (1_3) ◽  
pp. 168-168
Author(s):  
H. G. Hertz
Keyword(s):  
Solvent Systems ◽  
Hydrogen Bonded

Energy Dissipation Processes of Singlet Excited 1-Hydroxyfluorenone and its Hydrogen-Bonded Complex with N-Methylimidazole

2004 ◽  
Author(s):  
Krisztina Sebők-Nagy ◽  
László Biczók ◽  
Akimitsu Morimoto ◽  
Tetsuya Shimada ◽  
Haruo Inoue
Keyword(s):  
Energy Dissipation ◽  
Dissipation Processes ◽  
Hydrogen Bonded

A Pseudo Five-Fold Symmetrical Ligand Drives Geometric Frustration in Porous Metal-Organic and Hydrogen Bonded Frameworks

2020 ◽  
Author(s):  
Frederik Haase ◽  
Gavin Craig ◽  
Mickaele Bonneau ◽  
kunihisa sugimoto ◽  
Shuhei Furukawa
Keyword(s):  
Topological Defects ◽  
Porous Metal ◽  
Building Blocks ◽  
Structural Features ◽  
Equilibrium Structure ◽  
Sorption Behavior ◽  
Building Unit ◽  
Geometric Frustration ◽  
Secondary Building Units ◽  
Hydrogen Bonded

Reticular framework materials thrive on designability, but unexpected reaction outcomes are crucial in exploring new structures and functionalities. By combining “incompatible” building blocks, we employed geometric frustration in reticular materials leading to emergent structural features. The combination of a pseudo C<sub>5</sub> symmetrical organic building unit based on a pyrrole core, with a C<sub>4</sub> symmetrical copper paddlewheel synthon led to three distinct frameworks by tuning the synthetic conditions. The frameworks show structural features typical for geometric frustration: self-limiting assembly, internally stressed equilibrium structures and topological defects in the equilibrium structure, which manifested in the formation of a hydrogen bonded framework, distorted and broken secondary building units and dangling functional groups, respectively. The influence of geometric frustration on the CO<sub>2</sub> sorption behavior and the discovery of a new secondary building unit shows geometric frustration can serve as a strategy to obtain highly complex porous frameworks.

A Pseudo Five-Fold Symmetrical Ligand Drives Geometric Frustration in Porous Metal-Organic and Hydrogen Bonded Frameworks

2020 ◽  
Author(s):  
Frederik Haase ◽  
Gavin Craig ◽  
Mickaele Bonneau ◽  
kunihisa sugimoto ◽  
Shuhei Furukawa
Keyword(s):  
Topological Defects ◽  
Porous Metal ◽  
Building Blocks ◽  
Structural Features ◽  
Equilibrium Structure ◽  
Sorption Behavior ◽  
Building Unit ◽  
Geometric Frustration ◽  
Secondary Building Units ◽  
Hydrogen Bonded

Reticular framework materials thrive on designability, but unexpected reaction outcomes are crucial in exploring new structures and functionalities. By combining “incompatible” building blocks, we employed geometric frustration in reticular materials leading to emergent structural features. The combination of a pseudo C<sub>5</sub> symmetrical organic building unit based on a pyrrole core, with a C<sub>4</sub> symmetrical copper paddlewheel synthon led to three distinct frameworks by tuning the synthetic conditions. The frameworks show structural features typical for geometric frustration: self-limiting assembly, internally stressed equilibrium structures and topological defects in the equilibrium structure, which manifested in the formation of a hydrogen bonded framework, distorted and broken secondary building units and dangling functional groups, respectively. The influence of geometric frustration on the CO<sub>2</sub> sorption behavior and the discovery of a new secondary building unit shows geometric frustration can serve as a strategy to obtain highly complex porous frameworks.

Self-Recognizing π-π Stacking Interactions Designed for the Generation of Ultrastable Mesoporous Hydrogen-Bonded Organic Frameworks

2019 ◽  
Author(s):  
KAIKAI MA ◽  
Peng Li ◽  
John Xin ◽  
Yongwei Chen ◽  
Zhijie Chen ◽  
...  
Keyword(s):  
Pore Size ◽  
Fiber Composite ◽  
Aqueous Media ◽  
Stacking Interactions ◽  
Mustard Gas ◽  
X Ray Diffraction ◽  
X Ray ◽  
Expansion Strategy ◽  
Π Stacking ◽  
Hydrogen Bonded

Creating crystalline porous materials with large pores is typically challenging due to undesired interpen-etration, staggered stacking, or weakened framework stability. Here, we report a pore size expansion strategy by self-recognizing π-π stacking interactions in a series of two-dimensional (2D) hydrogen–bonded organic frameworks (HOFs), HOF-10x (x=0,1,2), self-assembled from pyrene-based tectons with systematic elongation of π-conjugated molecular arms. This strategy successfully avoids interpene-tration or staggered stacking and expands the pore size of HOF materials to access mesoporous HOF-102, which features a surface area of ~ 2,500 m2/g and the largest pore volume (1.3 cm3/g) to date among all reported HOFs. More importantly, HOF-102 shows significantly enhanced thermal and chemical stability as evidenced by powder x-ray diffraction and N2 isotherms after treatments in chal-lenging conditions. Such stability enables the adsorption of dyes and cytochrome c from aqueous media by HOF-102 and affords a processible HOF-102/fiber composite for the efficient photochemical detox-ification of a mustard gas simulant.

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