7

I searched for this on Google but I only got research articles in the SERP. I know of the concept of hydrogen bonds, that they are a special class of van der Waals forces between highly electronegative atoms ($\ce{F/O/N/Cl})$ and the hydrogen atom. I am asking if deuterium also exhibits the same hydrogen bonding, and how does its "$\ce{D}$ bond" compare to the hydrogen's original "$\ce{H}$ bond"?

paracetamol
  • 18,649
  • 29
  • 106
  • 169
Gaurang Tandon
  • 9,788
  • 11
  • 65
  • 118
  • 9
    Boiling point of D2O: 101.4°C. Does that answer your question? Also: https://en.wikipedia.org/wiki/Heavy_water – Karl Jan 13 '18 at 10:02
  • @Karl Do you mean to say that D2O possesses H-bonding, and that the "D bond" is in fact stronger than "H bond"? EDIT: Ok, I found this passage in Wikipedia "As a hydrogen bond with deuterium is slightly stronger than one involving ordinary hydrogen, in a highly deuterated environment, some normal reactions in cells are disrupted." I wonder why Google didn't catch it :/ – Gaurang Tandon Jan 13 '18 at 10:04
  • 2
    Why does water have a Bp of 100°C? In comparision CH4: -161, NH3: -33, SH2: -60°C. – Karl Jan 13 '18 at 10:05
  • @Karl Well I don't know. I always thought it was the opposite. We arbitrarily assigned 100degC to the boiling point of water. Water doesn't know what the temperature is anyway. – Gaurang Tandon Jan 13 '18 at 10:06
  • That's not the point. The Bp of water is extremely high, and that has one reason: hydrogen bonding. – Karl Jan 13 '18 at 10:09
  • @Karl And D2O has an even higher BP because of its stronger D-bond. Is that what you intend to say? – Gaurang Tandon Jan 13 '18 at 10:11
  • 4
    Btw. hydrogen bonding is NOT a vdW interaction but an exeptionally strong form of polar interaction. And nitrogen and chlorine don't do hydrogen bonding, only fluorine and oxygen. Bp HF: +20°C, HCl: -85 – Karl Jan 13 '18 at 10:14
  • @Karl I added Chlorine because of its exceptional H-bonding in stabilizing chloral hydrate. And ammonia does have H-bonds, so I am not really sure about what you just said. – Gaurang Tandon Jan 13 '18 at 10:17
  • Chlorine is NOT taking part in hydrogen bonds in chloral hydate! CCl3 is a strong electron widthdrawing group, and that stabilises the hydrate. Which makes regular O-H--O hydrogen bonds. – Karl Jan 13 '18 at 10:24
  • 3
    What do you mean by "SERP"? – paracetamol Jan 13 '18 at 10:27
  • 2
    @paracetamol Search Engine Results Page - one that's displayed when you use a search engine. – Gaurang Tandon Jan 13 '18 at 10:30
  • @Karl Oh! didn't know that before... – Gaurang Tandon Jan 13 '18 at 10:31
  • 9
    To say hydrogen bonds only form with oxygen and fluorine is a gross oversimplification. Many common elements can be both hydrogen bond donors and acceptors: carbon, selenium, sulfur, chlorine, iodine, phosphorus, cobalt, iron, manganese, even hydrogen itself in dihydrogen bonds. Also a misconception: the hydrogen bonds with oxygen and fluorine must always be stronger than others which is not true: see, e.g., doi: 10.1039/C7CP05265K. – Linear Christmas Jan 13 '18 at 12:21
  • @LinearChristmas Ok, I understand. Thank you for pointing out! – Gaurang Tandon Jan 13 '18 at 12:30
  • 2
    @GaurangTandon It was actually more directed at Karl's comment. Futhermore, I don't think that the slight difference in boiling points of $\ce{H2O}$ and $\ce{D2O}$ can immediately be translated into a stronger hydrogen bond. Helium-3 and helium-4 have boiling points of $\pu{3.19 K}$ and $\pu{4.23 K}$, for instance. In other words: boiling point does immediately signify a stronger intermolecular bond but whether it comes from a hydrogen bond needs to be proven separately. – Linear Christmas Jan 13 '18 at 12:35
  • @LinearChristmas "I don't think that the slight difference in H2OHX2O and D2ODX2O can immediately be translated into a stronger hydrogen bond." To be honest I was slightly wary of that myself at first. I didn't go deep enough to get that helium isotopic data, but yes, I agree with you. – Gaurang Tandon Jan 13 '18 at 12:37
  • @Linear That last comment of yours is a good point :-) However, in polar compounds (something helium is not), I'm still firm in my belief that dipole moments are ultimately what primarily governs boiling points. In light of your comment, I've revised my answer to accommodate your point. Thanks! – paracetamol Jan 13 '18 at 17:51
  • @LinearChristmas I just checked the link you give above (an article from last year!), and in the first sentence i read ..recent re-definition of hydrogen bonding... Could you point out what exactly they have re-defined? I find the idea of hydogen bonds to carbon very ridiculous, but perhaps I'm getting old. Or are we talking about funny ultravacuum gas-phase and argon-matrix species? – Karl Jan 14 '18 at 18:35
  • 1
    @Karl 1. Yes, it was redefined and improved upon, I think, in 2011. It contains a list of criteria. 2. The previous definition did not limit hydrogen bonds to $\ce{NOF}$ either, see 'usually (but not necessarily)'. 3. Indeed, I see that referencing one relatively new paper may have been confusing; it was the first to come to mind. There are more common examples, if you like, for example chloroform (1955) has carbon as a hydrogen-bond donor. – Linear Christmas Jan 14 '18 at 18:57
  • 1
    see also: IUPAC techical report which accompanied the redefinition, and explains the process in more detail – Linear Christmas Jan 14 '18 at 18:59
  • @LinearChristmas Thanks! So the gist is, in daily life, hydrogen bonds are FH-F,OH-O,NH-N (and permutations), but if you search for a proper definition, you come to realise that it can only be "there is some directed bonding" between the participants, and then you find there is a huge zoo of species that fit this description. For starters, every reaction intermediate where a proton is transfered. – Karl Jan 14 '18 at 19:46
  • 1
    Comments here are getting a little excessive, but they still seem to be productive. I noticed that some have been incorporated into answers, so can we either clean those up or shift this over to chat? – jonsca Jan 14 '18 at 21:34
  • @jonsca I've thought about it but haven't really reached a conclusion. The comments (although I am obviously biased) do deal with common misconceptions, and should thus stay. However, the volume is now indeed excessive. Maybe they can be transferred to chat with a disclaimer left by a moderator that the here-deleted exchange had some value? Not sure what the best strategy is; what do you think? – Linear Christmas Jan 17 '18 at 21:15
  • @LinearChristmas We can move to chat without deleting and people can remove what they see fit from here. Looks like things have petered off anyway. – jonsca Jan 17 '18 at 21:35
  • @jonsca One of you can summarize everything in 2-3 mega comments (giving credits where due) and move everything else to chat. Could be useful imho? – Gaurang Tandon Jan 18 '18 at 09:07

3 Answers3

7

(Based on ron's answer here on the inductive effect accorded by deuterium - do give that a read, and consider upvoting it)

Since deuterium has a higher mass than protium, simple Bohr theory tells us that the deuterium 1s electron will have a smaller orbital radius than the 1s electron orbiting the protium nucleus.

The smaller orbital radius for the deuterium electron translates into a shorter (and stronger) $\ce{C-D}$ bond length.

See the bottom half of ron's answer for the proof

In your case, that would mean a shorter $\ce{N/O/F-D}$ bond.

A shorter bond has less volume over which to spread the electron density (of the 1 electron contributed by $\ce{H}$ or $\ce{D}$) resulting in a higher electron density throughout the bond, and, consequently, more electron density at the carbon end of the bond. Therefore, the shorter $\ce{C-D}$ bond will have more electron density around the carbon end of the bond, than the longer $\ce{C-H}$ bond.

The net effect is that the shorter bond with deuterium increases the electron density at carbon, e.g. deuterium is inductively more electron donating than protium towards carbon.

So we can expect the $\ce{N/O/F-D}$ bond to be smaller and more polar than the corresponding bond with protium.

Karl very astutely pointed out that the boiling point of heavy water is higher than that of normal water. In light of the inferences drawn earlier, I took the liberty of interpreting this fact as being (at least somewhat) indicative of deuterium permitting a stronger hydrogen bond than protium.

As Linear Christmas pointed out, the variations in mass across different isotopes is known to affect boiling point (as in the case of helium). This is likely to contribute to some degree, to the increase in boiling point in heavy water. However, I'm still of the opinion that the higher dipole moment of $\ce{D2O}$ over $\ce{H2O}$ is the main cause for the higher boiling point.


Finis

Hydrogen bonding with deutrium does occur and should be, in theory (drawn from ron's answer), stronger than that with protium. The fact that heavy water $\ce{D-O-D}$ is more polar (and hence has a higher boiling point) than regular water $\ce{H-O-H}$, appears to be a consequence of this.

paracetamol
  • 18,649
  • 29
  • 106
  • 169
  • Everything in your answer seems great, except that ron's answer is about inductive effect in covalently bonded atoms. I am talking about H bonding in non-bonded atoms. How can we say that the factors influencing them will be the same? – Gaurang Tandon Jan 13 '18 at 10:33
  • 1
    I actually only wanted to point out that heavy water has practically the same high Bp. ;-) – Karl Jan 13 '18 at 10:33
  • 3
    @GaurangTandon I used ron's answer to explain why the $\ce{N/O/F-D}$ bond is more polar than its protium counterpart. H-bonding is largely an electrostatic dipole-dipole interaction. So if the covalent bonds (that effect H-bonding) are more polar, then the H-bonding is stronger :-) – paracetamol Jan 13 '18 at 10:36
  • @Karl I figured (from your follow-up comments under the OP) O:) – paracetamol Jan 13 '18 at 10:37
  • Perfect! Thanks :D I'll accept your answer in a day or two . – Gaurang Tandon Jan 13 '18 at 10:39
  • 1
    Do you know what's the reasoning for counting the much weaker N-H--N bond among the much stronger O-H--O or F-H--F hydrogen bonds? – Karl Jan 13 '18 at 10:39
  • @Karl Nope. Earlier I was under the impression that there was some (arbitrary) threshold M-H bond moment value that had to be crossed before you could call it a "hydrogen bond", but apparently that's not the case. So yeah, I'm curious...why is it? :-D – paracetamol Jan 13 '18 at 10:43
  • Well, I'm guessing that a hydrogen bond should, at least principally, be able to transfer the proton, while a merely polar interaction means that all covalent bonds are definitely permanent. But is that the definition? – Karl Jan 13 '18 at 10:48
  • @Karl Ah, that's insightful! But then $\ce{HCl}$ should also able to form "hydrogen bonds", but apparently, this gig only includes $\ce{N/O/F}$ :-( – paracetamol Jan 13 '18 at 10:51
  • 1
    Not necessarily. There's no autoprotolysis in HCl, i think. Or? Does $\ce{H2Cl+}$ exist? – Karl Jan 13 '18 at 11:26
  • @Karl Whelp! You're right ($\ce{HCl}$ protolysis happens in an aqueous solution) :-D – paracetamol Jan 13 '18 at 12:02
  • 1
    What about masses ; ? I was given this question/exercise many years ago. I didn't solve it nor I did it ast a follow up. Qualitatively it should raise the boiling point even further (extent might be very small). – Alchimista Jan 13 '18 at 14:39
  • @Karl H2Cl+ does exist and autoprotonation of HCl is small but not nonexistant. – Mithoron Jan 13 '18 at 22:04
  • @Mithoron But under any relevant conditions? I'm not sure if liquid HCl is relevant. ;-) Apart from this nitpicking, what do you say to this "definition" of a hydrogen bond i gave above? – Karl Jan 14 '18 at 00:56
  • @Karl "nitrogen and chlorine don't do hydrogen bonding" facepalm vide Linear's comment. – Mithoron Jan 14 '18 at 01:24
  • @Mithoron I meant " a hydrogen bond should, at least principally, be able to transfer the proton, while a merely polar interaction means that all covalent bonds are definitely permanent. " – Karl Jan 14 '18 at 18:38
1

In short:

Chemistry is about the last shell of electrons in the atoms. Nuclear differences are in the field of Physics. Deuterium is only a nuclear isotope of hydrogen, so no fundamental differences are to be expected in the chemical sphere.

Hydrogen bonding is a chemical property.

Raoul Kessels
  • 4,372
  • 8
  • 24
  • Yes, that's also another perspective to look at it! – Gaurang Tandon Jan 13 '18 at 16:39
  • Thank you. I do not want to discredit @paracetamol 's answer. Just to remember the fundamentals. Something my father, a Chemical Engineer, used to tell me. – Raoul Kessels Jan 13 '18 at 16:48
  • Yes, I understand :D – Gaurang Tandon Jan 13 '18 at 16:51
  • I think is not the best perspective tough. Not for fine details. Else we have to eliminate boiling point arguments as well and stop at rough level, such as D2O does react wit sodium and so on. (Of course it does). – Alchimista Jan 13 '18 at 16:54
  • 3
    Aha, this is something my teachers repeatedly sought to hammer into my brain :-) That nuclear differences don't affect the chemistry of substances is a general statement; it is usually (but not always) true. For instance, ron's answer (which is linked in my post), explains how hydrogen isotopes (which differ in the composition of their nucleus) produce different inductive effects, and the inductive effect is indeed a chemical phenomenon. O:) – paracetamol Jan 13 '18 at 17:31
  • Actually it is the good answer to the Q. My previous comment is on another line brought in by the discussion about boiling point. Mass differences count too:, even assuming the same H bond strength water and heavy water will be different, chemically (like in biochemistry fine details) and physicochemically ( b.p. , vibrations, etc...). – Alchimista Jan 16 '18 at 16:19
1

This is not at all an anwer, but the discussion above pointed to the 2011 IUPAC definition of hydrogen bonds, which I did not know about:

The hydrogen bond is an attractive interaction between a hydrogen atom from a molecule or a molecular fragment X–H in which X is more electronegative than H, and an atom or a group of atoms in the same or a different molecule, in which there is evidence of bond formation.

That definition paper from Pure and Applied Chemistry is accompanied by a technical report that gives history, examples, etc.

So, while hydrogen bonds are most well known for fluorine (FH-F), oxygen (OH-O) and nitrogen (NH-N) (and permutations), there is a huge zoo of other examples (e.g. reaction intermediates for proton transfers, etc) where this definition applies, and they include most of the periodic table except the electropositive metals.

(Any hydrogen bond of course also works with deuterium, just the stability and reaction dynamics are in most cases slightly different.)

Karl
  • 12,053
  • 2
  • 30
  • 61