A Theoretical Study of the Antioxidant Properties of Kanakugiol: the Cu(II) and Co(II)

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Antioxidant properties of kanakugiol revealed through the hydrogen atom transfer, electron transfer and M2+ (M2+ = Cu(II) or Co(II) ion) coordination ability mechanisms. A DFT study in vacuo and in solution

Food biophysics,

Tshepiso. J. Tsiepe, Mwadham. M. Kabanda*, Kemoabetswe. R. N. Serobatse

Department of Chemistry, Faculty of Agriculture, Science and Technology, School of Mathematical and Physical Science, North-West University (Mafikeng Campus), Private Bag X2046, Mmabatho 2735, South Africa

K-1-1a2a K-2-1a2a K-3-1a2a K-4-1a2b K-5-1a2b

K-6-1b2b K-7-1a2b K-8-1b2a K-9-1b2a

Fig. S1 Optimized conformers of kanakugiol, B3LYP/ 6-31+G(d,p) results in vacuo.

Food biophysics,

Tshepiso. J. Tsiepe, Mwadham. M. Kabanda*, Kemoabetswe. R. N. Serobatse

KCo-C2C3C4 KCo-C2C7 KCo-C1C7O9 KCo-C1C2 KCo-O9O2 KCo-C3O4O5 KCo-O3O4

C5C6C1 C8C9O9 C3C4C5C6

KCu-C2C3 KCu-C7O9 KCu-C7C8O9 KCu-C1C2 KCu-O9O2 KCu-O4O5 KCu-O3O4

C4C5C6C1 C3C4C5C6

Fig. S2 Molecular graphs for the Kanakugiol∙∙∙Co and Kanakugiol∙∙∙Cu complexes, UG96LYP/6-31G(d) results in vacuo.

Food biophysics,

Tshepiso. J. Tsiepe, Mwadham. M. Kabanda*, Kemoabetswe. R. N. Serobatse

KCo-C2C3C4 KCo-C2C7 KCo-C1C7O9 KCo-C1C2 KCo-O9O2 KCo-O3O4

C5C6C1 C8C9O9 C3C4C5C6

KCu-C2C3 KCu-C7O9 KCu-C1C2 KCu-O9O2 KCu-O4O5 KCu-O3O4

C4C5C6C1 C3C4C5C6

Fig. S3 Kanakugiol∙∙∙Co and Kanakugiol∙∙∙Cu complexes arranged in order of increasing relative stability. UG96LYP/6-31G(d) results in water solution.

Food biophysics,

Tshepiso. J. Tsiepe, Mwadham. M. Kabanda*, Kemoabetswe. R. N. Serobatse

Table S1. Binding and deformation energies (kcal/mol) for the complexes of kanakugiol with Co and Cu ions, UG96LYP/6-311+G(3df,2p) results in vacuo.

kanakugiol∙∙∙cobalt complexes / kanakugiol∙∙∙copper complexes
Ebinding / ∆Edef / ∆Ebind, without def / Ebinding / ∆Edef / ∆Ebind, without def
KCo-C2C3C4C5C6C1 / 324.5 / 18.6 / 305.9 / KCu-C2C3C4C5C6C1 / 340.5 / 18.3 / 322.3
KCo-C2C7C8C9O9 / 314.6 / 49.1 / 265.5 / KCu-C7O9 / 341.2 / 27.8 / 313.4
KCo-C1C7O9 / 310.9 / 60.9 / 249.9 / KCu-C7C8O9 / 341.2 / 27.9 / 313.4
KCo-C1C2C3C4C5C6 / 310.9 / 28.2 / 282.7 / KCu-C1C2C3C4C5C6 / 320.9 / 26.7 / 294.2
KCo-O9O2 / −a / 19.6 / −a / KCu-O9O2 / 347.3 / 20.2 / 327.2
KCo-C3O4O5 / 293.3 / 23.5 / 269.8 / KCu-O4O5 / 317.3 / 29.0 / 288.3
KCo-O3O4 / −a / 16.9 / −a / KCu-O3O4 / 315.0 / 17.3 / 297.7

aOn optimisation, the calculation fails to converge

Food biophysics,

Tshepiso. J. Tsiepe, Mwadham. M. Kabanda*, Kemoabetswe. R. N. Serobatse

Table S2. B3LYP/6-31G(d) Natural atomic orbital occupancies of some valence orbitals in the isolated metal ion and in a number of complexes with kanakugiol, results of the study in vacuo.

Isolated M2+ and the complexes / Orbitals and the corresponding natural atomic orbital occupancies
dxy / dxz / dyz / dx2y2 / dz2 / 4s
isolated Co / 1.44959 / 1.73131 / 1.21095 / 1.35852 / 1.24947 / 0.00000
KCo-C2C3C4C5C6C1 / 1.52625 / 1.38348 / 1.72705 / 1.55636 / 1.38378 / 0.12841
KCo-C2C7C8C9O9 / 1.56378 / 1.75784 / 1.32669 / 1.42340 / 1.41111 / 0.27832
KCo-C1C7O9 / 1.64908 / 1.32635 / 1.58714 / 1.20888 / 1.68550 / 0.32295
KCo-C1C2C3C4C5C6 / 1.73039 / 1.33438 / 1.28275 / 1.60460 / 1.80964 / 0.14398
KCo-O9O2 / 1.77259 / 1.73463 / 1.15840 / 1.30873 / 1.49920 / 0.32975
KCo-C3O4O5 / 1.57069 / 1.30970 / 1.36860 / 1.56250 / 1.86212 / 0.15455
KCo-O3O4 / 1.28927 / 1.29953 / 1.45993 / 1.77733 / 1.75500 / 0.37893
isolated Cu / 1.96825 / 1.33866 / 1.98276 / 1.71048 / 1.99966 / 0.00000
KCu-C2C3C4C5C6C1 / 1.86351 / 1.91764 / 1.92562 / 1.87909 / 1.94391 / 0.14793
KCu-C7O9 / 1.84099 / 1.93925 / 1.88453 / 1.94078 / 1.95075 / 0.26354
KCu-C7C8O9 / 1.87480 / 1.92531 / 1.89053 / 1.93303 / 1.93238 / 0.26442
KCu-C1C2C3C4C5C6 / 1.89026 / 1.93612 / 1.86979 / 1.90252 / 1.93538 / 0.23486
KCu-O9O2 / 1.93157 / 1.85056 / 1.84010 / 1.93011 / 1.93034 / 0.34307
KCu-O4O5 / 1.92483 / 1.86800 / 1.96120 / 1.93184 / 1.87651 / 0.34748
KCu-O3O4 / 1.88913 / 1.96000 / 1.89447 / 1.92854 / 1.90949 / 0.33695

Food biophysics,

Tshepiso. J. Tsiepe, Mwadham. M. Kabanda*, Kemoabetswe. R. N. Serobatse

Table S3. Atomic-Atomic Spin Densities data for the LigandM2+ complexes, UG96LYP/6-31G(d) results in vacuo.

complex / Bond type / Atomic-Atomic Spin density / complex / Bond type / Atomic-Atomic Spin density
KCo-C2C3C4C5C6C1 / Co···C2 / 0.001738 / KCu-C2C3C4C5C6C1 / Cu···C2 / -0.000019
Co···C3 / 0.004135 / Cu···C3 / 0.000007
Co···C4 / 0.002082 / Cu···C4 / -0.000004
Co···C5 / 0.003591 / Cu···C5 / 0.000006
Co···C6 / 0.003695 / Cu···C6 / -0.000028
Co···C1 / 0.002058 / Cu···C1 / 0.000006
KCo-C2C7C8C9O9 / Co-C2 / 0.015598 / KCu-C7C8O9 / Cu-C7 / 0.000216
Co-C7 / 0.026994 / Cu-C8 / -0.000280
Co-O9 / -0.004271 / Cu-O9 / 0.000131
KCo-C6C7O9 / Co-C2 / -0.011698 / KCu-C7C8O9 / Co-C7 / 0.000313
Co-C7 / 0.017493 / Co-C8 / -0.000445
Co-O9 / -0.009903 / Co-O9 / 0.000143
Co-C3 / 0.022558
KCo-C1C2C3C4C5C6 / Co-C1 / 0.003572 / KCu-C1C2C3C4C5C6 / Cu-C1 / 0.001148
Co-C2 / -0.003377 / Cu-C2 / 0.009856
Co-C3 / -0.005048 / Cu-C3 / 0.015152
Co-C4 / 0.000674 / Cu-C4 / -0.006967
Co-C5 / 0.002416 / Cu-C5 / 0.008345
Co-C6 / -0.000087 / Cu-C6 / 0.003924
KCo-O9O2 / Co-O9 / 0.003532 / KCu-O9O2 / Cu-O9 / -0.002154
Co-O2 / 0.001697 / Cu-O2 / 0.001627
KCo-C3O4O5 / Co-C5 / 0.021659 / KCu-O5C6 / Cu-O5 / 0.000802
Co-O4 / 0.011528 / Cu-C6 / -0.000066
Co-O5 / -0.002304
KCo-O3O4 / Co-O3 / 0.023896
Co-O4 / 0.032547