Multiwfn forum

ducly

Member

Registered: 2024-11-04

Posts: 5

Analysis of sobEDAw results

Dear Prof. Lu

I am trying to apply sobEDAw method to analyze the transistion state of the enantiodetermining step in my reaction. The TS4 and TS4' is corresponding to Re face and Si face attack while TS4 and TS2 are leading to different regio-isomer. I am expecting that TS4 would has significant pi-pi stabilization than the other which should has a strongest dispersion interaction, I guess. The result I got is shown below. The electrostatic and dispersion terms of all 3 transition state are comparable. The only significant difference is Orbital energy, I had read the orignial paper of sobEDA. However, as a synthetic chemist, I don't have much understanding about the orbital interaction terms. Would it represent for pi-pi interaction (weak interaction) for the complex that I am studying.

    TS4    TS4’    TS2
ΔE_int interaction (kcal/mol)    -79.75    -69.49    -72.56
ΔE_els electrostatic (kcal/mol)    -86.11    -85.35    -87.69
ΔE_xrep exchange-repulsion (kcal/mol)    258.64    246.65    261.82
ΔE_orb  orbital (kcal/mol)    -172.97    -151.38    -166.95
ΔE_disp dispersion (kcal/mol)    -79.31    -79.41    -79.73

I am looking forward to your help.

Thank you so much,
Best regards,
Duc

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 2,014

Website

Re: Analysis of sobEDAw results

Dear Duc,

Orbital interaction is completely irrelevant to pi-pi stacking effect. It is well known that pi-pi interaction essentially comes from the dispersion interaction between parallelly distributed pi electrons. See relevant discussions and references in my recent work Chem. Eur. J. 2024, 30, e202402227.

I suggest using the specific function for dispersion interaction analysis implemented in Multiwfn last year to carry out your analysis, see Section Section 3.24.4 for introduction and Section 4.21.4 for example (please make sure that you are using latest Multiwfn version and reading the latest manual). In this function, you are able to easily define fragments to obtain dispersion interaction energy between them. For two pi-conjugated fragments forming pi-pi stacking with each other, the dispersion interaction energy between the two fragments directly exhibits the strength of pi-pi interaction.

Best,

Tian

ducly

Member

Registered: 2024-11-04

Posts: 5

Re: Analysis of sobEDAw results

Dear Prof. Lu

Thank you so much for your suggestion. I am wondering if you can help me with a more chemically intuitive explain for the orbital term in sobEDAw. It will help me alot. I have read the paper, and I saw the approach by using the area of interaction by IGMH to evaluate the interaction is very useful. Can you please guide me how to extract the area value for interaction by VMD.

Thank you so much,
Best regards,
Duc

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 2,014

Website

Re: Analysis of sobEDAw results

Dear Duc,

If you hope to provide a deeper insight into the orbital interaction term, I suggest using the ETS-NOCV function in Multiwfn, which further decomposes this term into various chemically meaningful components, see Section 4.23 of Multiwfn manual for examples, and see the relevant illustration in the recent Multiwfn original paper (J. Chem. Phys., 161, 082503 (2024)).

I don't exactly know what is the "the area of interaction by IGMH" you referred to, if you mean the area of IGMH isosurface, it is not directly related to orbital interaction, but closely related to strength of dispersion (see Fig. S2 of my paper Chem. Eur. J., 30, e202402227 (2024), it seen that the area is almost linearly proportional to pi-pi interaction energy energy). The isosurface area can be easily measured by ChimeraX visualization software.

Best,

Tian