Talk:Hydrogen bond

Lewis acid/base

Under 'Definitions and general characteristics' the article stated that "the donor is a Lewis base". The hydrogen bond donor is a proton donor or electron pair acceptor, i.e. it is a Lewis acid, not base. The proton acceptor is the base. Changed accordingly. — Preceding unsigned comment added by 2A02:8071:AB5:7A00:D49E:1A5A:7F78:DDAB (talk) 19:26, 11 August 2019 (UTC)[reply]

Theory, covalent nature, references

About this : "The initial theory of hydrogen bonding proposed by Linus Pauling suggested that the hydrogen bonds had a partial covalent nature. This remained a controversial conclusion until the late 1990's when NMR techniques were employed by F. Cordier et al. to transfer information between hydrogen-bonded nuclei, a feat that would only be possible if the hydrogen bond contained some covalent character." and the reference given (Cordier et al., J. Magn Res. 1999, 140, 510-512): I have just looked at this article and it is clearly written in it that other examples of J coupling through hydrogen bonds were known at least one year before them. The most ancient article about this phenomenon seems to be : A. J. Dingley and S. Grzesiek, J. Am. Chem. Soc. 120, 8293–8297 (1998). I hesitated to modify the article myself as I am not sure to understand: is the observation of such a coupling an evidence of the covalent nature of the hydrogen bond ? Or is there something new and decisive on this question in the article of Cordier et al. ? I wonder because they don't claim it at all in their article...

Other articles that might be relevant (I haven't read any of them, but they were cited in Weinhold and Landis's Valency and Bonding, Cambridge University Press, 2005):

Summers, MF. J Am Chem Soc 114, 4391 (1992)
Wütrich K. Proc Natl Acad Sci USA 95, 14147 (1998)
Shenderovich, SN et al. Ber Bunsenges Phys Chem 102, 422 (1998)
Cornilescu JS. J Am Chem Soc 121, 2949 (1999)
Wang YX. J Biomol NMR 14, 181 (1999)

There have also been discoveries of long-range quantum-mechanical phase coherence that have been used as evidence of the covalent character of the H-bond:

Isaacs ED et al. Phys Rev Lett 82, 600 (1999); Science 283 (1999)

I think it would be best not to try to attribute the discovery of evidence of covalent character in hydrogen bonds to any specific author in the article text, because it can be controversial. We can cite some of these references, of course, or a more indirect source such as Valency and Bonding (p. 583). --Itub 09:54, 3 April 2007 (UTC)[reply]

Missing Sources

The section on synthetic polymers contains no citations for any of the information. None of the sources in the References discuss the topic. Any possible sources? Lnj19 (talk) 17:10, 29 April 2020 (UTC)[reply]

Assessment comment

The comment(s) below were originally left at Talk:Hydrogen bond/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.

Rated "top" as high school/SAT biology content and important mechanism in biochemistry and molecular biology. - tameeria 00:01, 11 March 2007 (UTC)[reply]

Last edited at 00:01, 11 March 2007 (UTC). Substituted at 18:34, 29 April 2016 (UTC)

Possible Reference

Hydrogen bonding: Homing in on a tricky chemical concept

Paul Needham

Studies in History and Philosophy of Science Part A

Volume 44, Issue 1, March 2013, Pages 51-65

https://doi.org/10.1016/j.shpsa.2012.04.001

Christopher King (talk) 18:48, 19 October 2018 (UTC)[reply]

Done--Smokefoot (talk) 21:17, 19 October 2018 (UTC)[reply]

Contradictory Statement in the Opening Paragraph

The opening paragraph here seems to contain a contradictory statement. The first sentence states (emphasis mine):

A hydrogen bond ... is a primarily electrostatic force of attraction ...

The final sentence then claims:

While hydrogen bonding has both covalent and electrostatic contributions ... the primary contribution is covalent.

As far as I can tell, these two statements directly contradict each other. That said, I don't personally have enough knowledge to edit—could someone with the appropriate expertise please reword or clarify?

~ Rent-Yr-Chemicals (talk) 02:45, 19 November 2020 (UTC)[reply]

hydrogen bonding by C, Cl and S

how can we say that chloroform have h bonds with C as donor? what are the examples where S and Cl act as donors?

also i wanted to know if H bonding occurs by lone pair present on donor or by partial negative charge deveoped on it?Vanshita poddar (talk) 09:55, 27 April 2021 (UTC)vanshita poddar[reply]

Proposed merge of Resonance-assisted hydrogen bond into Hydrogen bond

Stubby article with one reference that is not mentioned at parent topic. Ost (talk) 06:30, 19 December 2021 (UTC)[reply]

I say merge it in. It's not a significant enough topic to warrant it's own page. --Tautomers_{(T C)} 00:48, 21 December 2021 (UTC)[reply]

Expansion needed: C–H donors

The article says there are donors other than O-H, N-H, and F–H, and hints that possibly there are acceptors other than an electronegative atom with a lone pair. But the rest of the article does not give any such examples. The classic model, with only those three types of donors and only O/N lone-pair acceptors seems to be fairly standard even up through college-level intro-orgo textbooks. Our article needs to be expanded with examples of these other types. Even simple aromatic C–H are known as donors (benzene and ferrocene as an interesting specific exampledoi:10.1021/om4004972), and aromatic π systems as acceptors (with suggestions "XH...π" are even common in biological systems).doi:10.1021/jp410917x DMacks (talk) 02:52, 16 October 2022 (UTC)[reply]

Found a few revelant reviews:

There are also some more general reviews that discuss C–H···X hydrogen bonds:

Finally, here are some reviews on other aspects of hydrogen bonding that could be used to enrich the article:

There's a reasonable discussion of hydrogen bonding in the context of organic chemistry in the sixth edition of March's Advanced Organic Chemistry (pages 106–113). It mentions terminal alkynes (RC≡CH), chloroform and some other halogenated alkanes, and HCN as C–H hydrogen bond donors. Focus is on C–H⋯O=C. It also discusses S–H donors, and Cl, S, X⁻, HS⁻, isocyanides (R–⁺N≡C⁻), double bonds, triple bonds, aromatic rings and cyclopropane rings as acceptors (some very weak). It cites CH⋯N/CH⋯O and R₃N⁺−C−H···OC. On pages 367–368, the normal mechanism of acid-base reactions is introduced and the first step is the formation of a hydrogen-bonded complex. Although this implies hydrogen bonds form when carbon acids react, the authors note proton transfers from a carbon atom are usually much slower than for O or N due to weak or absent hydrogen bonding, structural reorganisation of the conjugate base and rearrangement of solvent molecules.

Ben (talk) 11:07, 16 October 2022 (UTC)[reply]

Donor Definition

I may be misunderstanding the source, so I did not change it, but it does not seem like the source supports that "the one (atom) covalently bound to the hydrogen is the proton donor." The source linked does not seem to mention a "proton donor", so it would be best to refer to it as hydrogen bond donor, as this source defines the wording. More importantly, the whole group is referred to as the donor, in the linked IUPAC source, with no reference to a single atom being a donor. "X–H represents the hydrogen bond donor"^[1] implies that the X, H and the bond (the group itself) is rightly referred to as a donor and not any individual atom. This problem also exists in the nomenclature of the introduction, if it is an actual problem in the definitions section. Another source would need to be used for "donating group" to be used this way, and the statement that IUPAC recommends this nomenclature would also need to be removed. MScottH (talk) 21:26, 12 February 2024 (UTC)[reply]

References

^ Arunan, Elangannan; Desiraju, Gautam R.; Klein, Roger A.; Sadlej, Joanna; Scheiner, Steve; Alkorta, Ibon; Clary, David C.; Crabtree, Robert H.; Dannenberg, Joseph J. (2011-07-08). "Definition of the hydrogen bond (IUPAC Recommendations 2011)". Pure and Applied Chemistry. 83 (8): 1637–1641. doi:10.1351/PAC-REC-10-01-02. ISSN 1365-3075. S2CID 97688573.

Structural Details

There is a note in the table asking for verification. I also have a question about the water-HF angle of 46º. If the electrons of water are pyramidal/tetrahedral or so, this describes an hydrogen bond angle is which oxygen should not have electrons. Is this a typo, or do I not understand. Petedskier (talk) 12:25, 29 June 2024 (UTC)[reply]

[:0-1] Arunan, Elangannan; Desiraju, Gautam R.; Klein, Roger A.; Sadlej, Joanna; Scheiner, Steve; Alkorta, Ibon; Clary, David C.; Crabtree, Robert H.; Dannenberg, Joseph J. (2011-07-08). "Definition of the hydrogen bond (IUPAC Recommendations 2011)". Pure and Applied Chemistry. 83 (8): 1637–1641. doi:10.1351/PAC-REC-10-01-02. ISSN 1365-3075. S2CID 97688573.

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