scholarly journals Metal-free [2+2+1] cycloaddition polymerization of alkynes, nitriles, and oxygen atoms to functional polyoxazoles

RSC Advances ◽  
2020 ◽  
Vol 10 (41) ◽  
pp. 24368-24373 ◽  
Author(s):  
Lichao Dong ◽  
Tian Lan ◽  
Yin Liang ◽  
Shifeng Guo ◽  
Hao Zhang
Keyword(s):  
Trifluoromethanesulfonic Acid ◽  
Metal Free ◽  
Oxygen Atoms

The metal-free [2+2+1] cycloaddition polymerization of alkynes, nitriles, and O-atoms for the regioselective assembly of highly substituted oxazole compounds has been achieved by the use of iodosobenzene (PhIO) with trifluoromethanesulfonic acid (TfOH).

scholarly journals Morpholin-2-one Derivatives via Intramolecular Acid-Catalyzed Hydroamination

Synthesis ◽  
2019 ◽  
Vol 51 (07) ◽  
pp. 1643-1648 ◽  
Author(s):  
David Knight ◽  
Thomas Wirth ◽  
Abdul Hadi Aldmairi
Keyword(s):  
Amino Acids ◽  
Catalytic Amount ◽  
Practical Method ◽  
Trifluoromethanesulfonic Acid ◽  
Reaction Conditions ◽  
Available N ◽  
Metal Free ◽  
Acid Catalyzed

Substituted morpholin-2-one derivatives were readily obtained in two steps starting from commercially available N-protected amino acids. In a metal-free and practical method, a catalytic amount of trifluoromethanesulfonic acid was sufficient to generate morpholinones under mild reaction conditions in an intramolecular hydroamination reaction in good to excellent yields.

Efficient imidation of C(sp3)–H bonds adjacent to oxygen atoms of aryl ethers under metal-free conditions

2014 ◽  
Vol 50 (85) ◽  
pp. 12880-12883 ◽  
Author(s):  
Kai Sun ◽  
Xin Wang ◽  
Gang Li ◽  
Zhonghong Zhu ◽  
Yongqing Jiang ◽  
...  
Keyword(s):  
Formation Reaction ◽  
Metal Free ◽  
Aryl Ethers ◽  
First Time ◽  
Oxygen Atoms

A metal-free intermolecular oxidative C–N formation reaction of aryl ethers with saccharins was realized for the first time.

scholarly journals Complexes of Cu(II) Ions and Noncovalent Interactions in Systems with L-Aspartic Acid and Cytidine-5'-Monophosphate

2008 ◽  
Vol 2008 ◽  
pp. 1-10 ◽  
Author(s):  
Romualda Bregier-Jarzebowska ◽  
Anna Gasowska ◽  
Lechosław Lomozik
Keyword(s):  
Aspartic Acid ◽  
Metal Ion ◽  
Molecular Complexes ◽  
Main Reaction ◽  
Carboxyl Groups ◽  
Reaction Centre ◽  
Solution Ph ◽  
Metal Free ◽  
Reaction Centres ◽  
Oxygen Atoms

Interactions between aspartic acid (Asp) and cytidine-5-monophosphate (CMP) in metal-free systems as well as the coordination of Cu(II) ions with the above ligands were studied. The composition and overall stability constants of the species formed in those systems were determined by the potentiometric method, and the interaction centres in the ligands were identified by the spectral methods UV-Vis, EPR, NMR, and IR. In metal-free systems, the formation of adducts, in which each ligand has both positive and negative reaction centres, was established. The main reaction centres in Asp are the oxygen atoms of carboxyl groups and the nitrogen atom of the amine group, while the main reaction centre in CMP at low pH is the N(3) atom. With increasing pH, the efficiency of the phosphate group of the nucleotide in the interactions significantly increases, and the efficiency of carboxyl groups in Asp decreases. The noncovalent reaction centres in the ligands are simultaneously the potential sites of metal-ion coordination. The mode of coordination in the complexes formed in the ternary systems was established. The sites of coordination depend clearly on the solution pH. In the molecular complexesML⋯L, metallation involves the oxygen atoms of the carboxyl groups of the amino acid, while the protonated nucleotide is in the outer coordination sphere and interacts noncovalently with the anchoringCuHx(Asp) species. The influence of the metal ions on the weak interactions between the biomolecules was established.

scholarly journals Correction: Metal-free [2+2+1] cycloaddition polymerization of alkynes, nitriles, and oxygen atoms to functional polyoxazoles

RSC Advances ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 2292-2292
Author(s):  
Lichao Dong ◽  
Tian Lan ◽  
Yin Liang ◽  
Shifeng Guo ◽  
Hao Zhang
Keyword(s):  
Metal Free ◽  
Oxygen Atoms

Correction for ‘Metal-free [2+2+1] cycloaddition polymerization of alkynes, nitriles, and oxygen atoms to functional polyoxazoles’ by Lichao Dong et al., RSC Adv., 2020, 10, 24368–24373, DOI: 10.1039/D0RA04249H.

Metal-Free [2 + 2 + 1] Annulation of Alkynes, Nitriles, and Oxygen Atoms: Iodine(III)-Mediated Synthesis of Highly Substituted Oxazoles

2013 ◽  
Vol 15 (11) ◽  
pp. 2672-2675 ◽  
Author(s):  
Akio Saito ◽  
Akihiro Taniguchi ◽  
Yui Kambara ◽  
Yuji Hanzawa
Keyword(s):  
Metal Free ◽  
Oxygen Atoms

ChemInform Abstract: Efficient Imidation of C(sp3)-H Bonds Adjacent to Oxygen Atoms of Aryl Ethers under Metal-Free Conditions.

ChemInform ◽  
2015 ◽  
Vol 46 (12) ◽  
pp. no-no
Author(s):  
Kai Sun ◽  
Xin Wang ◽  
Gang Li ◽  
Zhonghong Zhu ◽  
Yongqing Jiang ◽  
...  
Keyword(s):  
Metal Free ◽  
Aryl Ethers ◽  
Oxygen Atoms

ChemInform Abstract: Metal-Free [2 + 2 + 1] Annulation of Alkynes, Nitriles, and Oxygen Atoms: Iodine(III)-Mediated Synthesis of Highly Substituted Oxazoles.

ChemInform ◽  
2013 ◽  
Vol 44 (40) ◽  
pp. no-no
Author(s):  
Akio Saito ◽  
Akihiro Taniguchi ◽  
Yui Kambara ◽  
Yuji Hanzawa
Keyword(s):  
Metal Free ◽  
Oxygen Atoms

scholarly journals Retraction: Metal-free [2+2+1] cycloaddition polymerization of alkynes, nitriles, and oxygen atoms to functional polyoxazoles

RSC Advances ◽  
2021 ◽  
Vol 11 (27) ◽  
pp. 16200-16200
Author(s):  
Lichao Dong ◽  
Tian Lan ◽  
Yin Liang ◽  
Shifeng Guo ◽  
Hao Zhang
Keyword(s):  
Metal Free ◽  
Oxygen Atoms

Retraction of ‘Metal-free [2+2+1] cycloaddition polymerization of alkynes, nitriles, and oxygen atoms to functional polyoxazoles’ by Lichao Dong et al., RSC Adv., 2020, 10, 24368–24373, DOI: 10.1039/D0RA04249H.

The Shadow Widths of Very Small Particles are Formed Independently of the Metal Cap Build Up on the Particle

1981 ◽  
Vol 39 ◽  
pp. 568-569
Author(s):  
George C. Ruben
Keyword(s):  
Gold Particle ◽  
Film Surface ◽  
Small Particles ◽  
Geometric Process ◽  
Metal Free ◽  
Shadow Area

The formation of shadows behind small particles has been thought to be a geometric process (GP) where the metal cap build up on the particle creates a shadow width the same size as or larger than the particle. This GP cannot explain why gold particle shadow widths are generally larger than the gold particle and may have no appreciable metal cap build up (fig. 1). Ruben and Telford have suggested that particle shadow widths are formed by the width dependent deflection of shadow metal (SM) lateral to and infront of the particle. The trajectory of the deflected SM is determined by the incoming shadow angle (45°). Since there can be up to 1.4 times (at 45°) more SM directly striking the particle than the film surface, a ridge of metal nuclei lateral to and infront of the particle can be formed. This ridge in turn can prevent some SM from directly landing in the metal free shadow area. However, the SM that does land in the shadow area (not blocked by the particle or its ridge) does not stick and apparently surface migrates into the SM film behind the particle.

Recent advancement in the electrocatalytic synthesis of ammonia

Nanoscale ◽  
2020 ◽  
Vol 12 (15) ◽  
pp. 8065-8094 ◽  
Author(s):  
Xudong Wen ◽  
Jingqi Guan
Keyword(s):  
Metal Oxide ◽  
Oxide Catalysts ◽  
Single Atom ◽  
Metal Oxide Catalysts ◽  
Metal Free ◽  
Recent Advancement ◽  
Nanocomposite Catalysts

Different kinds of electrocatalysts used in NRR electrocatalysis (including single atom catalysts, metal oxide catalysts, nanocomposite catalysts, and metal free catalysts) are introduced.

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