Nonstabilised Azomethine Ylids from N-Oxides: Unravelling the Deprotonation of N-Methylmorpholine N-Oxide

2014 ◽  
Vol 67 (9) ◽  
pp. 1309 ◽  
Author(s):  
Paul Malek Mirzayans ◽  
Elizabeth H. Krenske ◽  
Craig M. Williams
Keyword(s):  
Density Functional Theory ◽  
Low Temperature ◽  
High Temperatures ◽  
Density Functional ◽  
Temperature Reaction ◽  
Functional Theory ◽  
Strong Base ◽  
Mechanisms Of Formation ◽  
Cyclic Systems

Nonstabilised azomethine ylids (NAYs) are useful 1,3-dipoles, but their synthetic applications are restricted by the high temperatures often needed for their generation, and by an incomplete understanding of the effect of heteroatoms in cyclic systems. We have examined the behaviour of N-methylmorpholine N-oxide (NMO) as a NAY precursor in the Roussi reaction (low-temperature reaction of an N-oxide with strong base). The choice of base is critical to achieving cycloadduct formation. We report synthetic and computational (density functional theory) investigations of the products obtained with different bases and their mechanisms of formation.

scholarly journals Nanoribbons with Non-Alternant Topology from Fusion of Polyazulene: Carbon Allotropes Beyond Graphene

2019 ◽  
Author(s):  
Qitang Fan ◽  
Daniel Martin-Jimenez ◽  
Daniel Ebeling ◽  
Claudio K. Krug ◽  
Lea Brechmann ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Low Temperature ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Scanning Probe ◽  
Two Dimensional ◽  
Reaction Step ◽  
Functional Theory ◽  
Carbon Allotropes ◽  
Temperature Scanning

Various two-dimensional (2D) carbon allotropes with non-alternant topologies, such as pentaheptites and phagraphene, have been proposed. Predictions indicate that these metastable carbon polymorphs, which contain odd-numbered rings, possess unusual (opto)electronic properties. However, none of these materials has been achieved experimentally due to synthetic challenges. In this work, by using on-surface synthesis, nanoribbons of the non-alternant graphene allotropes, phagraphene and tetra-penta-hepta(TPH)-graphene have been obtained by dehydrogenative C-C coupling of 2,6-polyazulene chains. These chains were formed in a preceding reaction step via on-surface Ullmann coupling of 2,6-dibromoazulene. Low-temperature scanning probe microscopies with CO-functionalized tip and density functional theory calculations have been used to elucidate their structural properties. <br>

Interface dipoles of Ir(ppy)3on Cu(111)

Nanoscale ◽  
2019 ◽  
Vol 11 (26) ◽  
pp. 12695-12703 ◽  
Author(s):  
Fabian Queck ◽  
Florian Albrecht ◽  
Pingo Mutombo ◽  
Ondrej Krejci ◽  
Pavel Jelínek ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Low Temperature ◽  
Scanning Probe Microscopy ◽  
Density Functional ◽  
Transition Metal Complex ◽  
Density Functional Theory Calculations ◽  
Scanning Probe ◽  
Functional Theory ◽  
Adsorption Geometry ◽  
Temperature Scanning

The interplay of adsorption geometry and interface dipoles of the transition-metal complex Ir(ppy)3on Cu(111) was studied using low-temperature scanning probe microscopy and density-functional-theory calculations.

Nanoribbons with Non-Alternant Topology from Fusion of Polyazulene: Carbon Allotropes Beyond Graphene

2019 ◽  
Author(s):  
Qitang Fan ◽  
Daniel Martin-Jimenez ◽  
Daniel Ebeling ◽  
Claudio K. Krug ◽  
Lea Brechmann ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Low Temperature ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Scanning Probe ◽  
Two Dimensional ◽  
Reaction Step ◽  
Functional Theory ◽  
Carbon Allotropes ◽  
Temperature Scanning

Various two-dimensional (2D) carbon allotropes with non-alternant topologies, such as pentaheptites and phagraphene, have been proposed. Predictions indicate that these metastable carbon polymorphs, which contain odd-numbered rings, possess unusual (opto)electronic properties. However, none of these materials has been achieved experimentally due to synthetic challenges. In this work, by using on-surface synthesis, nanoribbons of the non-alternant graphene allotropes, phagraphene and tetra-penta-hepta(TPH)-graphene have been obtained by dehydrogenative C-C coupling of 2,6-polyazulene chains. These chains were formed in a preceding reaction step via on-surface Ullmann coupling of 2,6-dibromoazulene. Low-temperature scanning probe microscopies with CO-functionalized tip and density functional theory calculations have been used to elucidate their structural properties. <br>

Photoisomerization of acetyl methyl iminoxy radical in low-temperature argon matrices studied by density functional theory

2000 ◽  
Vol 328 (3) ◽  
pp. 283-290 ◽  
Author(s):  
Satoshi Kudoh ◽  
Tomohiro Uechi ◽  
Masao Takayanagi ◽  
Munetaka Nakata ◽  
Heinz Frei
Keyword(s):  
Density Functional Theory ◽  
Low Temperature ◽  
Density Functional ◽  
Functional Theory ◽  
Argon Matrices
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