Dear Krishna, many thanks for sharing this interesting technical question with the RG community. As a synthetic inorganic chemist I'm absolutely no expert in theoretical chemistry. However, even without any calculations I can predict that the Hg2+ ion will go for the nitrogen donor sites of the Schiff base ligand. In this context, please have a look at the following very instructive review article:
Affinity of Divalent Mercury Towards Nitrogen Donor Ligands
Article Affinity of Divalent Mercury Towards Nitrogen Donor Ligands
The paper has not yet been posted as public full text on RG, but both authors have RG profiles. Thus you can easily request the full text directly from one of them via RG. If you contact Gerd Meyer at https://www.researchgate.net/profile/Gerd-Meyer-2 please pass my best regards to him!
Please also have a look at the following potentially useful article in which a thorough investigation of Hg2+ Schiff base complexes is reported:
A Chemodosimetric Approach for Fluorimetric Detection of Hg2+ Ions by Trinuclear Zn(II)/Cd(II) Schiff Base Complex: First Case of Intermediate Trapping in a Chemodosimetric Approach
Article A Chemodosimetric Approach for Fluorimetric Detection of Hg2...
It is shown in this study that the central mercury atom is coordinated only through the nitrogen sites of the ligand, while the –OH group remains uncoordinated. Here too you can request the full text directly from one of the authors. In my personal experience most authors respond rather quickly to full text requests.
Good luck wth your work and best wishes, Frank Edelmann