The helical supramolecular assembly of oligopyridylamide foldamers in aqueous media can be guided by adenosine diphosphates

2021 ◽  
Author(s):  
Debabrata Maity ◽  
Andrew D. Hamilton
Keyword(s):  
Aqueous Media ◽  
Supramolecular Assembly ◽  
Side Chain ◽  
Metal Free ◽  
Physiological Conditions ◽  
Left Handed ◽  
Adenosine Phosphates

A metal-free and achiral tri-pyridylamide foldamer, DM 11, containing a critical naphthalimide side chain self-assembles in a left-handed helical manner in the presence of chiral adenosine phosphates, under physiological conditions.

Dissociation of imino proton(s) of a highly water-soluble metal-free phthalocyanine and determination of its pKa value in water

2013 ◽  
Vol 17 (06n07) ◽  
pp. 447-453 ◽  
Author(s):  
Hiroaki Isago ◽  
Harumi Fujita
Keyword(s):  
Aqueous Media ◽  
Thermal Reaction ◽  
Water Soluble ◽  
Acid Dissociation ◽  
Acid Dissociation Constant ◽  
Metal Free ◽  
Imino Proton ◽  
Pka Value ◽  
Triton X

Dissociation of imino proton(s) in the cavity of the macrocycle of a highly water-soluble, metal-free phthalocyanine ( H 2( H 4 tsppc ); where H 4 tsppc denotes tetrakis{(2′,6′-dimethyl-4′-sulfonic acid)phenoxy}phthalocyaninate) in ethanolic and aqueous solutions has spectrophotometrically been investigated. The spectral changes associated with reaction with NaOH have been found to involve one-proton transfer process in aqueous media while two-protons process in ethanolic media. The acid-dissociation constant of the first imino proton in water (in the presence of Triton X-100) has been determined to be 12.5 ± 0.2 (as pKa) at 25 °C. The doubly deprotonated species in EtOH has been easily converted to its corresponding cobalt(II) derivative by thermal reaction with anhydrous CoCl 2.

Artificial light-harvesting systems based on macrocycles-assisted supramolecular assembly in aqueous media

2021 ◽  
Author(s):  
Kaiya Wang ◽  
Krishnasamy Velmurugan ◽  
Bin Li ◽  
Xiao-Yu Hu
Keyword(s):  
Light Harvesting ◽  
Aqueous Media ◽  
Supramolecular Assembly ◽  
Routine Activities ◽  
Chemical Energy ◽  
Artificial Light ◽  
Natural Systems ◽  
Harvesting Systems

Light-harvesting, which converts sunlight into chemical energy by natural systems such as plants, bacteria, is one of the most universal routine activities in nature. So far, various artificial light-harvesting systems...

scholarly journals Surfactant Micelles Enable Metal-Free Spirocyclization of Keto-Ynamides and Access to Aza-Spiro Scaffolds in Aqueous Media

2019 ◽  
Vol 2019 (41) ◽  
pp. 6989-6993
Author(s):  
Frédéric Beltran ◽  
Andrea V. Vela-Gonzalez ◽  
Tatiana Knaub ◽  
Marc Schmutz ◽  
Marie Pierre Krafft ◽  
...  
Keyword(s):  
Aqueous Media ◽  
Surfactant Micelles ◽  
Metal Free

Facile transition of poly[d(TG)·d(CA)] into a left-handed helix in physiological conditions

Nature ◽  
1983 ◽  
Vol 302 (5909) ◽  
pp. 632-634 ◽  
Author(s):  
David B. Haniford ◽  
David E. Pulleyblank
Keyword(s):  
Physiological Conditions ◽  
Left Handed

New metal-free catalytic degradation systems with carbon dots for thymol blue

2017 ◽  
Vol 41 (22) ◽  
pp. 13365-13369 ◽  
Author(s):  
Cui Zheng ◽  
Xueqin An ◽  
Tianxiang Yin
Keyword(s):  
Catalytic System ◽  
Carbon Dots ◽  
Aqueous Media ◽  
Catalytic Degradation ◽  
Thymol Blue ◽  
Metal Free

A metal-free catalytic system with carbon dots as a catalyst for thymol blue degradation in slightly alkaline aqueous media.

Synthesis of 2,3-Dihydrotryptamines from Amide Solvents and Acyclic Materials through Metal-Free Amidoalkylarylation of Unactivated Alkenes

Synlett ◽  
2019 ◽  
Vol 30 (11) ◽  
pp. 1329-1333
Author(s):  
Yubin Ji ◽  
Siping Yang ◽  
Shiyi Lin ◽  
Yan Wang ◽  
Chenfeng Ji ◽  
...  
Keyword(s):  
Aqueous Media ◽  
Metal Free ◽  
Simple Operation ◽  
Reaction Proceeds

The first synthesis of 2,3-dihydrotryptamines from acyclic materials and an exo-selective amidoalkylation/cyclization cascade of N-allyl anilines through α-C(sp3)–H functionalization of simple amides across unactivated alkenes are presented. This reaction proceeds in mixed aqueous media and under metal-free conditions and features a broad substrate scope and a simple operation.

scholarly journals C5-Substituted 2-Selenouridines Ensure Efficient Base Pairing with Guanosine; Consequences for Reading the NNG-3′ Synonymous mRNA Codons

2020 ◽  
Vol 21 (8) ◽  
pp. 2882 ◽  
Author(s):  
Grazyna Leszczynska ◽  
Marek Cypryk ◽  
Bartlomiej Gostynski ◽  
Klaudia Sadowska ◽  
Paulina Herman ◽  
...  
Keyword(s):  
Gene Expression ◽  
Density Functional ◽  
Negative Charge ◽  
Positive Charge ◽  
Dominant Role ◽  
Regulation Of Gene Expression ◽  
Side Chain ◽  
Functional Theory ◽  
Physiological Conditions ◽  
Synonymous Codons

5-Substituted 2-selenouridines (R5Se2U) are post-transcriptional modifications present in the first anticodon position of transfer RNA. Their functional role in the regulation of gene expression is elusive. Here, we present efficient syntheses of 5-methylaminomethyl-2-selenouridine (1, mnm5Se2U), 5-carboxymethylaminomethyl-2-selenouridine (2, cmnm5Se2U), and Se2U (3) alongside the crystal structure of the latter nucleoside. By using pH-dependent potentiometric titration, pKa values for the N3H groups of 1–3 were assessed to be significantly lower compared to their 2-thio- and 2-oxo-congeners. At physiological conditions (pH 7.4), Se2-uridines 1 and 2 preferentially adopted the zwitterionic form (ZI, ca. 90%), with the positive charge located at the amino alkyl side chain and the negative charge at the Se2-N3-O4 edge. As shown by density functional theory (DFT) calculations, this ZI form efficiently bound to guanine, forming the so-called “new wobble base pair”, which was accepted by the ribosome architecture. These data suggest that the tRNA anticodons with wobble R5Se2Us may preferentially read the 5′-NNG-3′ synonymous codons, unlike their 2-thio- and 2-oxo-precursors, which preferentially read the 5′-NNA-3′ codons. Thus, the interplay between the levels of U-, S2U- and Se2U-tRNA may have a dominant role in the epitranscriptomic regulation of gene expression via reading of the synonymous 3′-A- and 3′-G-ending codons.

scholarly journals Transition‐Metal‐Free Direct C‐H Arylation of Thiophene in Aqueous Media via Potassium Peroxymonosulfate

2019 ◽  
Vol 4 (29) ◽  
pp. 8516-8521
Author(s):  
Sezer Özenler ◽  
Hakan Kaya ◽  
Nuran Elmaci ◽  
Umit Hakan Yildiz
Keyword(s):  
Transition Metal ◽  
Aqueous Media ◽  
Metal Free ◽  
Potassium Peroxymonosulfate
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