In all cases, when two diastereomeric transition structures are possible, the one with the endo hydrogen, exo lone pair was predicted to have a lower activation barrier. This behavior can be explained by the n -蟺 and n - n loan pair repulsion interaction between the dienophile and ...
Thiophene oxides, where two pairs of lone pair electrons are consumed for bond formation with oxygen atoms, are no longer aromatic. Their chemistry has now... J Nakayama,Y Sugihara - 《Topics in Current Chemistry》 被引量: 45发表: 1999年 ...
The DFT calculations with the hybrid exchange-correlation functional B3LYP (Becke's three-parameter (B3) exchange in conjunction with the Lee–Yang–Parr's (LYP) correlation functional) which are especially important in systems containing extensive electron conjugation and/or electron lone pairs [7]....
The results of the calculations show that APO has a relatively strong intramolecular hydrogen bond with a N⋯O distance of 2.658 Ǻ. Our theoretical calculations demonstrate that the hydrogen bond strength increases when that one of the hydrogen atoms on the nitrogen atom of APO is substituted...
生物化学英文课件Biochemistry-chapter 3 Chapter3AminoAcidsandthePrimary StructuresofProteins 3.1OutlineofProteins3.2StructuresofAminoAcids3.3OtherAminoAcidsandAmino AcidDerivatives3.4IonizationofAminoAcids3.5ChemicalreactionsofAAs:3.6PeptideBondsLinkAminoAcids inProteins 3.7ProteinPurificationTechniques3.8Amino...
In all cases, when two diastereomeric transition structures are possible, the one with the endo hydrogen, exo lone pair was predicted to have a lower activation barrier. This behavior can be explained by the n-蟺 and n-n loan pair repulsion interaction between the dienophile and diene ...