Questions tagged [hydrogen-bond]

Bond between covalently bound hydrogen atom and atom possessing a lone pair of electrons.

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Physical significance of double-well potential in quantum bonding

I'm currently studying about the hydrogen bond's Potential Energy Surface (PES) pattern. As per literature, single point energy obtained from Density Functional Theory (DFT) using MP2 approximation ...
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Does increasing # of hydrogen bonds decrease the strength of these bonds?

I saw the question, "Is the strength of hydrogen bonding greater in hydrogen peroxide or water?" and it reminded me of a question I had about hydrogen bonding: If an oxygen on a water has a hydrogen ...
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Hydrogen bond strength of trichloromethane and chloromethane

Chloromethane has a larger dipole moment than trichloromethane. Does that mean that the hydrogen bond (C-H...O type) between chloromethane and acetone is stronger than that of trichloromethane and ...
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Strongest hydrogen bond between neutral molecules?

It is known that very strong hydrogen bonds can occur in charged systems, such as $\ce{[F-}\ce{-H+-F-]}$, while hydrogen bonds in neutral systems are much weaker in comparison. What is the strongest ...
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Tools for investigating hydrogen bonding

What would be the best tool to investigate local molecular organization in liquid mixtures due to hydrogen bonding? For example, I might want to look at how water molecules hydrogen bond to PNIPAM vs ...
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255 views

Does alcohol hydrogen in the enol tautomer of a β-dicarbonyl have sp² character?

My reasoning for the somewhat implausible "$\mathrm{sp^2}$" character of the hydrogen between these two oxygens on the enol structure of the right comes from recognizing that if it were, then we would ...
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Examples of intramolecular hydrogen bonding closing bond angles

Okay, we've established that intramolecular hydrogen bonding can exist in molecules, and doesn't always serve the purpose of closing the bond angle at least relative to other stereoisomers of the same ...
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Diazo Coupling reaction with para substituted phenol?

Usually Diazo coupling occurs at para position until the para position is occupied , in which case coupling occurs at ortho position . While solving questions I found in both the cases as shown , ...
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Hydrogen bonds: 1 donor with 2 acceptors at the same time possible (or vice versa)?

Can 1 donor (eg N-H) facilitate 2 H-bonds with 2 different acceptors (eg 2x O) at the same time (assuming that both are within range and angle constraint)? i.e. building an "h-bond triangle"? Is it ...
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Why does Pubchem show cis-1,3-cyclohexanediol with the hydroxyls in the equatorial position?

I am a beginning organic chemistry student and trying to reason about something based on information in my book, but seeing that Pubchem gives a different structure than I'd expect. In considering a ...
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Hydrogen Bonding by Carbenes

A hydrogen bond is formed between hydrogen attached to highly electronegative atoms (nitrogen, oxygen, and fluorine) which are small in size too and the non-bonding pair of electrons of another such ...
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Hydrogen Bonding in Water (MO theory)

Valence Bond Theory tells us that each of the “sp3” (in reality, 44% s character) oxygen line pairs in water can act as electron donors, but observing the MO diagram for water tells us that the 2 non-...
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It is easier to iron cotton clothes when slightly wet, why?

As the title says, why is it easier to iron cotton clothes when slightly damp ? Has this got something to do with the hydrogen bonding in cotton ?
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which oxygen atom make intramolecular hydrogen bond in salicyclic acid?

When I googled about intramolecular hydrogen bonding in Salicylic acid, I found that there are two type of hydrogen bonding. Which one is more appropriate? And another question, if there ARE two ...
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Increase of peak intensity in case of hydrogen bonding

Typical motif in case of hydrogen bonds is charge transfer from electron rich acceptor Y to (usually) anti-bonding X-H σ* orbital. If so, the X-H bonding distance increases, bond weakens, stretching ...
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Explain the effect of intramolecular hydrogen bonding on solubilities in cold and hot water?

There is a statement given in my textbook (Cengage, Organic Chemistry (Part 1), page 4.33) which is as follows: (I edited the statement to make it simpler) One can account for the solubilities of ...
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How to characterise lipophilicity?

I was provided with a drug compound which is filling a hydrophobic pocket. The R group is changed and effects on the potency was measured; $\ce{R = -H, -CH3, -CH2F}$ were tested. As expected, the more ...
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How to determine the pH range at which maximum hydrate is present?

Question: Find the $\mathrm{pH}$ range at which maximum hydrate is present in a solution of oxaloacetic acid (given $\mathrm{pK_a}$ of $\ce{-COOH}$ in the left is $=2.2$ and on the right is $=3.98$)...
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How do water molecules overcome the van der waals distance and form hydrogen bonds?

I read in Voet & Voet that the hydrogen bonds are at least 0.5 angstrom shorter than the calculated van der waals distance. As I understand, van der waals distance is the distance of closest ...
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Comparing strengths of Hydrogen Bonds

What kind of a bond is the Hydrogen bond? Is it electrostatic forces of attraction or more like a partial coordinate bond? What pair of atoms would provide us the strongest Hydrogen bond? If we ...
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580 views

reference or data on internal hydrogen bond strength

As suggested by the title, I am looking for data on the strength of different internal hydrogen bond configurations. In general, an internal hydrogen bond may form when the donor and acceptor are ...
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309 views

Number of hydrogen bonds of organic compounds?

How to count the organic molecules ' hydrogen bonds in average? What are the numbers of hydrogen bonds formed among alcohols ,alkanoic acids ,aldehyde , ketones , amine ,amide , and ether when they ...
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Why does energy need to be “compensated” in order for solvation to occur?

I am currently learning about the physical properties of alcohols. I understand that the main intermolecular forces between alcohols and water are hydrogen bonds. When these two are mixed, the ...