scholarly journals Endohedral Hydrogen Bonding Templates the Formation of a Highly Strained Covalent Organic Cage Compound

2021 ◽  
Author(s):  
Natalie Schäfer ◽  
Michael Bühler ◽  
Lisa Heyer ◽  
Merle I. S. Röhr ◽  
Florian Beuerle
Keyword(s):  
Hydrogen Bonding ◽  
Cage Compound ◽  
Highly Strained

scholarly journals Endohedral Hydrogen Bonding Templates the Formation of a Highly Strained Covalent Organic Cage Compound

2020 ◽  
Author(s):  
Natalie Schäfer ◽  
Michael Bühler ◽  
Lisa Heyer ◽  
Merle Röhr ◽  
Florian Beuerle
Keyword(s):  
Hydrogen Bonding ◽  
Benzoic Acid ◽  
Strain Energy ◽  
Acid Group ◽  
Bite Angle ◽  
Trigonal Bipyramidal ◽  
Cage Compound ◽  
Additional Strain ◽  
Dynamics Simulations ◽  
Highly Strained

A highly strained covalent organic cage compound was synthesized from hexahydroxy tribenzotriquinacene (TBTQ) and a meta-terphenyl-based diboronic acid with an additional benzoic acid substituent in 2’-position. Usually, a 120° bite angle in the unsubstituted ditopic linker favors the formation of a [4+6] cage assembly. Here we show that introduction of the benzoic acid group leads to a perfectly preorganized circular hydrogen-bonding array in the cavity of a trigonal-bipyramidal [2+3] cage, which energetically overcompensates the additional strain energy caused by the larger mismatch in bite angles for the smaller assembly. The strained cage compound was analyzed by mass spectrometry and <sup>1</sup>H, <sup>13</sup>C and DOSY NMR spectroscopy. DFT calculations revealed the energetic contribution of the hydrogen-bonding template to the cage stability. Furthermore, molecular dynamics simulations on early intermediates indicate an additional kinetic effect, as hydrogen-bonding also preorganizes and rigidifies small oligomers to facilitate the exclusive formation of smaller and more strained macrocycles and cages.

scholarly journals Endohedral Hydrogen Bonding Templates the Formation of a Highly Strained Covalent Organic Cage Compound

2020 ◽  
Author(s):  
Natalie Schäfer ◽  
Michael Bühler ◽  
Lisa Heyer ◽  
Merle Röhr ◽  
Florian Beuerle
Keyword(s):  
Hydrogen Bonding ◽  
Benzoic Acid ◽  
Strain Energy ◽  
Acid Group ◽  
Bite Angle ◽  
Trigonal Bipyramidal ◽  
Cage Compound ◽  
Additional Strain ◽  
Dynamics Simulations ◽  
Highly Strained

A highly strained covalent organic cage compound was synthesized from hexahydroxy tribenzotriquinacene (TBTQ) and a meta-terphenyl-based diboronic acid with an additional benzoic acid substituent in 2’-position. Usually, a 120° bite angle in the unsubstituted ditopic linker favors the formation of a [4+6] cage assembly. Here we show that introduction of the benzoic acid group leads to a perfectly preorganized circular hydrogen-bonding array in the cavity of a trigonal-bipyramidal [2+3] cage, which energetically overcompensates the additional strain energy caused by the larger mismatch in bite angles for the smaller assembly. The strained cage compound was analyzed by mass spectrometry and <sup>1</sup>H, <sup>13</sup>C and DOSY NMR spectroscopy. DFT calculations revealed the energetic contribution of the hydrogen-bonding template to the cage stability. Furthermore, molecular dynamics simulations on early intermediates indicate an additional kinetic effect, as hydrogen-bonding also preorganizes and rigidifies small oligomers to facilitate the exclusive formation of smaller and more strained macrocycles and cages.

scholarly journals Cross-strand disulfides in the hydrogen bonding site of antiparallel β-sheet (aCSDhs): Forbidden disulfides that are highly strained, easily broken

2018 ◽  
Vol 28 (1) ◽  
pp. 239-256
Author(s):  
Naomi L. Haworth ◽  
Michael J. Wouters ◽  
Morgan O. Hunter ◽  
Lixia Ma ◽  
Merridee A. Wouters
Keyword(s):  
Hydrogen Bonding ◽  
Highly Strained ◽  
Β Sheet ◽  
Hydrogen Bonding Site ◽  
Bonding Site

Hydrogen bonding in liquid methanol at ambient conditions and at high pressure

2000 ◽  
Vol 98 (3) ◽  
pp. 125-134 ◽  
Author(s):  
T. Weitkamp, J. Neuefeind, H. E. Fisch
Keyword(s):  
High Pressure ◽  
Hydrogen Bonding ◽  
Ambient Conditions

Fluorescence and pi-hydrogen bonding in naphthols

1968 ◽  
Vol 65 ◽  
pp. 1587-1589 ◽  
Author(s):  
Bithika Ghosh ◽  
Sadhan Basu
Keyword(s):  
Hydrogen Bonding

Theoretical study of intramolecular hydrogen bonding and molecular geometry of 2-trifluoromethylphenol

10.1002/jcc.2 ◽  
1996 ◽  
Vol 17 (16) ◽  
pp. 1804-1819 ◽  
Author(s):  
Attila Kov�cs ◽  
Istv�n Kolossv�ry ◽  
G�bor I. Csonka ◽  
Istv�n Hargittai
Keyword(s):  
Hydrogen Bonding ◽  
Theoretical Study ◽  
Molecular Geometry ◽  
Intramolecular Hydrogen Bonding ◽  
Intramolecular Hydrogen

PEMANFAATAN GLISERIN DARI RESIDU GLISERIN SEBAGAI PLASTICIZER UNTUK PEMBUATAN BIOPLASTIK DENGAN BAHAN BAKU PATI BONGGOL PISANG KEPOK

2017 ◽  
Vol 5 (4) ◽  
pp. 26-32 ◽  
Author(s):  
Azaria Robiana ◽  
M. Yashin Nahar ◽  
Hamidah Harahap
Keyword(s):  
Tensile Strength ◽  
Hydrogen Bonding ◽  
Fatty Acid ◽  
Maximum Yield ◽  
Sem Analysis ◽  
Water Molecules ◽  
Banana Weevil ◽  
Gelatinization Temperature ◽  
Recharge Area ◽  
Maximum Quantity

Glycerin residue is waste oleochemical industry that still contain glycerin. To produce quality and maximum quantity of glycerin, then research the effect of pH acidification using phosphoric acid. Glycerin analysis includes the analysis of pH, Fatty Acid and Ester (FAE), and analysis of the levels of glycerin. The maximum yield obtained at pH acidification 2 is grading 91,60% glycerin and Fatty Acid and Ester (FAE) 3,63 meq/100 g. Glycerin obtained is used as a plasticizer in the manufacture of bioplastics. Manufacture of bioplastics using the method of pouring a solution with varying concentrations of starch banana weevil (5% w/v and 7% w/v), variations of the addition of glycerin (1 ml, 3 ml, 5 ml and 7 ml), and a variety of gelatinization temperature (60°C, 70°C, and 80°C). Analysis of bioplastics include FTIR testing, tensile strength that is supported by SEM analysis. The results obtained in the analysis of FTIR does not form a new cluster on bioplastics starch banana weevil, but only a shift in the recharge area only, it is due to the addition of O-H groups originating from water molecules that enter the polysaccharide through a mechanism gelatinitation that generates interaction hydrogen bonding strengthened. The maximum tensile strength of bioplastics produced at a concentration of starch 7% w/v, 1 ml glycerine and gelatinization temperature of 80°C is 3,430 MPa. While the tensile strength bioplastic decreased with increasing glycerin which can be shown from the results of SEM where there is a crack, indentations and lumps of starch insoluble.

Hydrogen bonding and conformations in echitamine salts

1963 ◽  
Vol 119 (3-4) ◽  
pp. 252-256 ◽  
Author(s):  
Brahama D. Sharma ◽  
Richard E. Marsh ◽  
Jerry Donohue
Keyword(s):  
Hydrogen Bonding
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