organic chemistry - Number of gauche interactions in an alkane ...
2015年10月2日 · In most organic classes, the gauche interaction between methyl groups or alkyl groups is frequently discussed. The answers you included (2,3,3) are correct. Looking at the middle molecule (b) in your figure, there are 3 gauche interactions. They are between. the front methyl and the back ethyl.
How can the gauche-effect be explained? - Chemistry Stack …
2015年10月16日 · 19. The gauche effect is commonly explained with LCAO-based bond orbitals. LCAO is short for linear combination of atomic orbitals and implies that we can take two atomic orbitals ϕ1,ϕ2 ϕ 1, ϕ 2 and create two molecular orbitals ψ1,ψ2 ψ 1, ψ 2 from them by linear combination: ψ1 =a1ϕ1 +b1ϕ2 ψ 1 = a 1 ϕ 1 + b 1 ϕ 2 and ψ2 =a2ϕ1 ...
organic chemistry - Is there a gauche interaction between C-3 and …
2019年9月23日 · Axial methylcyclohexane has two gauche interactions. One is between the CH 3-C 1 bond and the C 2-C 3 bond shown in red. The dihedral (torsional) angle is ~60 o. Given the plane of symmetry passing through CH 3-C 1-C 4, the second gauche interaction is on the opposite side of the plane (CH 3-C 1 bond and the C 6-C 5 bond). Each of these ...
organic chemistry - What is the difference between steric strain …
2015年10月3日 · In butane, the gauche conformation experiences steric strain. But the eclipsed conformation at 0 degrees has substantial amounts of both steric strain and torsional strain. What is the difference?
organic chemistry - Gauche effect and bond length - Chemistry …
2016年9月29日 · CHX3−CFX3 CFX3−CFX3. Many of these cases hinge on some weird effect. Evidently the gauche form of 1,2-Difluoroethane is more stable than the anti form which is sort of weird. This wikipedia article on the list CC bond of gauche 1,2-Difluoroethane as 150 pm and anti form as 151.4 pm. This says 151.2 pm for C-C bond in 1,1,2,2-tetrafluoroethane.
organic chemistry - Which ethanol derivatives display the gauche …
2020年5月19日 · Figure 4. OCCN gauche structures with an intramolecular H-bond for 2-aminoethanol (7) and 2-nitroethanol (9); Conformations 8 and 10 indicate disrupted H-bonds after rotations by approximately 120º about the O-C axes. So it seems like all the groups shown here can show the gauche effect on the grounds of intramolecular hydrogen bonding,and so ...
organic chemistry - Stability of Gauche and Anti form in …
2020年10月2日 · $\begingroup$ in gauche form there is intramolecular hydrogen bonding between H and F which makes it stable... $\endgroup$ – maverick Commented Oct 3, 2020 at 13:58
organic chemistry - Why does Pubchem show cis-1,3 …
2019年11月4日 · Klein's Organic Chemistry [2, p. 166] gives in a different table the value of two $\ce{OH-H}$ 1,3-diaxial interactions in a monosubstituted cycloalkane to be 4.2 kJ/mol. It seems to me like the OH's have steric interactions with each other (3.8 kJ/mol), and they each have an interaction with an axial H (4.2 kJ/mol for both of them).
organic chemistry - Hydrogen bonding in staggered vs eclipsed ...
2016年3月11日 · $\begingroup$ "Last semester in organic chemistry 1, we learned that gauche conformations have lower energy/higher stability." Note that in most cases the anti conformation is more stable than the gauche. In a few molecules such as ethylene glycol and difluoroethane the gauche is more stable then the anti. $\endgroup$ –
organic chemistry - Conformations of butane - Chemistry Stack …
2020年6月10日 · 1. Just to be clear, your drawn figures are for butane and the book's figure is for propane. – jerepierre. May 23, 2014 at 15:54. Add a comment. Some years ago I did a (relaxed) rotational scan of n-butane for the purpose of showing that fatty acids are all-trans. That is also why I found the graph in Awesome's answer some kind of disturbing ...