Organic quantum chemistry—XVI

Allinger, Norman L.; Gilardeau, C.; Chow, Li Hui

doi:10.1016/s0040-4020(01)82512-6

Cited by 31 publications

(9 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…While the problem of the ground state of cyclobutadiene was solved, the relative energy between both square states was somewhat controversial. While MO methods wrongly predicted a lower triplet state at the square structure, GVB and SC calculations correctly described the ordering of the states, with the 1 B 1g state being from 10 to 14 kcal mol −1 lower in energy than the 3 A 2g . Finally, the distortion of the singlet ground state from a square to a rectangular structure is explained by the second‐order Jahn‐Teller effect .…”

Section: Many Electron Chemical Bondsmentioning

confidence: 91%

The Nature of the Chemical Bond from a Quantum Mechanical Interference Perspective

2017

View full text Add to dashboard Cite

The analysis of the chemical bond in a variety of systems exhibiting distinct bonding patterns was performed using the Generalized Product Function Energy Partitioning (GPF‐EP) approach in order to verify the role played by quantum interference. Diatomic and polyatomic molecules, with single, double and triple bonds, with different degrees of polarity, linear or branched, cyclic or not, conjugated and aromatics, have been considered. In all cases the conclusion was exactly the same: for each bond of the molecule the energy partitioning results showed that the main contribution to the depth of the potential wells comes from the interference term. From the quantum interference perspective the minimum requirement for a chemical bond to be formed is one electron and two interfering one‐electron states belonging to different atoms. As a consequence, all chemical bonds are covalent in the sense that it takes a one‐electron state of each atom to form the bond, irrespective of its polarity.

show abstract

Section: Many Electron Chemical Bondsmentioning

confidence: 91%

The Nature of the Chemical Bond from a Quantum Mechanical Interference Perspective

2017

View full text Add to dashboard Cite

show abstract

“…Hydroxyl groups of P4HS may be oxidized to quinone ones, 22 however both FT-IR and 1 H and 13 C NMR spectra showed that the number of quinonic groups was almost negligible.…”

Section: Polymer Characterizationmentioning

confidence: 99%

Hydrogen-Bonded Polymer Blends. Blends Containing Poly(4-hydroxystyrene-co-4-methoxystyrene) Copolymers

Sanchís¹,

Prolongo²,

Rubio

et al. 1995

Polym J

View full text Add to dashboard Cite

ABSTRACT:The miscibility between partially methoxylated poly(4-hydroystyrene) with poly(vinyl acetate), poly(methyl acrylate), and poly(ethyl acrylate) was assessed based on glass transition temperature over the entire composition range. Quantitative analyses of the fraction of hydrogen bonded carbonyl groups were made by FT-IR spectroscopy for all systems. Good correlation between thermal behavior and infrared results was observed. The results are discussed considering the influence of two factors on miscibility, decrease of -OH---C = 0 hydrogen bonds in the blend and autoassociation as a function of methoxylation degree.

show abstract

“…Irradiation of tetramethylcyclobutenedicarboxylic anhydride (5)[321 affords a complicated mixture of products[331. The crucial intermediates for formation of the twelve isolated and identified products are the monoketone ( 8 ) and the diketone ( 9 ) . Formation of these two compounds can be regarded iis evidencing the intermcdiacy of tetramethylcyclobutadiene ( 6 ) and tetramethylcyclopentadienone (7).…”

Section: Methylated Cyclobutadienesmentioning

confidence: 99%

“…On irradiation in a matrix under the same conditions these adducts give the same product mixture as is found on irradiation of ( 5 ) in solution at room temperature. Thus it is clear that on irradiation of(5) no adduct ( 8 ) or dimer (9) is present prior to thawing of the matrix and that tetramethylcyclobutadiene (6) and cyclopentadienone ( 7 ) must be frozen in the matrix as monomers. Provided that the matrix is kept at -196 C, the yellow color is retained for several hours after the lamp has been switched off.…”

Section: Methylated Cyclobutadienesmentioning

confidence: 99%

The Cyclobutadiene Problem

Maier

1974

Angew. Chem. Int. Ed. Engl.

167

View full text Add to dashboard Cite

Cyclobutadiene has recently become the center of reawakened interest. By use of the matrix isolation technique, cyclobutadienes can now be prepared as monomers frozen in matrices. Thus both the unsubstituted parent compound and its alkyl‐substituted derivatives are amenable to study. The present progress report surveys the entire field; however, particular emphasis is placed on the author's own results from investigations concerning this classical problem of organic chemistry.

show abstract

Organic quantum chemistry—XVI

Cited by 31 publications

References 7 publications

The Nature of the Chemical Bond from a Quantum Mechanical Interference Perspective

The Nature of the Chemical Bond from a Quantum Mechanical Interference Perspective

Hydrogen-Bonded Polymer Blends. Blends Containing Poly(4-hydroxystyrene-co-4-methoxystyrene) Copolymers

The Cyclobutadiene Problem

Contact Info

Product

Resources

About