Dear Partha,
are you familiar with the IUPAC definition of a hydrogen bond? E.g. here:
http://publications.iupac.org/pac/pdf/2011/pdf/8308x1637.pdf
Based on that, it’s clear that there is indeed a POSSIBILITY of a H-bond, as you have a potential H-bond donor (N-H) and two possible acceptors (the N atoms, and the pi-electron system). However, it also seems likely that the interaction will be quite weak, to the point of the existence of a H-bond being a borderline case, likely depending on the conditions (see the footnotes in the linked pdf).
Some quick-and-dirty calculations on my laptop (using Spartan ’20, wB97xD and a 6-31+G(d) basis set set - and yes I know there are better basis sets available but this should be good enough for the present purpose) confirm this: for the H-bond to the N atom, the distance is pretty large (H…N is almost 2.4 Å), the NHN angle is far from linear (about 129 degrees), the N-H bond length increase and vibrational redshift (compared to isolated methyl amine) are on the order of 0.002 Å and a few wavenumbers, respectively, and interaction energy is only about 20 kJ/mol (of which a lot, possibly even most, is probably just basis set superposition error due to my small basis set).
For the H-bond to the pi-system, the distance (to the center of the ring) is even longer (almost 2.6 Å), the interaction energy is even lower (about 10 kJ/mol), the N-H bond length is identical (to 0.001 Å) to isolated methyl amine, and the frequencies are actually blueshifted by a few cm-1 (the latter may just be an artefact though). So this is likely not a H-bond at all, as per the IUPAC definition
Whether or not you want to call the first interaction (from the methyl amine NH to the pyrazine N) a H-bond really really depends on what you want to do with this information.
Best regards,
Theo Kurtén
(University of Helsinki, Finland)
From: owner-chemistry+theo.kurten==helsinki.fi__ccl.net <owner-chemistry+theo.kurten==helsinki.fi__ccl.net> on behalf of Partha Sengupta anapspsmo=gmail.com <owner-chemistry__ccl.net>
Date: Friday, 5. May 2023 at 17.15
To: Kurten, Theo C <theo.kurten__helsinki.fi>
Subject: CCL: hydrogen bondI am not interested in ChatGpt. I ask the question to be answered from a chemical point of view. I repeat the question again" Is there any possibility between the hydrogen bond formation between pyrazine and methyl amine". If there is any chance please give me the references.
Partha
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Dr. Partha Sarathi Sengupta
Associate Professor
Vivekananda Mahavidyalaya, Burdwan