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Jishnunil

Member

Registered: 2022-02-12

Posts: 7

Binding energy and Hydrogen bond energy

Dear Prof. Lu

I have calculated the binding energy of a dimer of a palladium(II) complex considering two monomers at the optimized dimer geometry using BP86-D3 functional with def2-TZVP basis set. The binding energy calculation has given the value -30.34 kcal/mol. The QTAIM topology analysis shows two N-H...O HBs in the dimer with several other weak HB interactions and ring CPs. The HB binding energy calculations using the equation BE≈−223.08×rho(rBCP)+0.7423 (for neutral HB) proposed by you and your collaborators show that the energy of the two N-H...O HB binding energies as -5.50 and 7.07 kcal/mol. The sum of these energies is far from the computed total binding energy of the dimer. I cannot account for this difference (17.77 kcal/mol). What may be the possible reason behind these observations? Any advice from your side will be highly appreciated.

With best regards

Jis

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,773

Website

Re: Binding energy and Hydrogen bond energy

Dear Jis,

There are many possible reasons, for example:

(1) The binding energy you evaluated using BP86-D3/def2-TZVP may be not accurate enough. In particular, BSSE should be taken into account.

(2) The prediction formula given in my JCC paper was fitted for B3LYP-D3(BJ)/ma-TZVPP level, which is different to the one you used.

(3) The contribution from other interactions is notable and thus cannot be simply ignored.

(4) The two H-bonds have evident coupling and therefore their contributions to binding energy cannot be simply summed up. I cannot talk more about this without your geometry.

Best regards,

Tian

Jishnunil

Member

Registered: 2022-02-12

Posts: 7

Re: Binding energy and Hydrogen bond energy

Dear Prof. Lu

Thank u so much for the reply.

Jis