Practical and computational studies on novel Schiff base complexes derived from green synthesis approach: Conductometry as well as in-vitro screening supported by in-silico study Reem Shah a , Hanadi Katouah a , Anas A. Sedayo b , Matokah Abualnaja a , Meshari M. Aljohani c , Fawaz Saad a , Rania Zaky d , Nashwa M. El-Metwaly a,d, ⁎ a Department of Chemistry, Faculty of Applied Science, Umm-Al-Qura University, Makkah, Saudi Arabia b Department of X-ray, Maternity and Children Hospital, Ministry of Health, Makkah, Saudi Arabia c Depertment of Chemistry, Faculty of Science, Tabuk University, Tabuk 71491, Saudi Arabia d Department of Chemistry, Faculty of Science, Mansoura University, El-Gomhoria Street, Egypt abstract article info Article history: Received 11 July 2020 Received in revised form 15 August 2020 Accepted 20 August 2020 Available online 24 August 2020 Keywords: Green synthesis Schiff base complexes EDX SEM Conductometry Computerized studies In-vitro In-silico A new Schiff base ligand was prepared and characterized then used to synthesize new metal ion complexes using ball milling technique. These complexes were elucidated by analytical, spectral and conformational tools, to es- tablish their formulae. Mononuclear complexes (1M:1L) were proposed through neutral or mononegative mode within bidentate or tridentate binding. Octahedral configuration was proposed for all complexes except Pd(II) complex has square-planer geometry. EDX, SEM and XRD were used to known the elemental percentage, topographic features as well as the magnitude of crystallinity. Kinetic and thermodynamic parameters were es- timated by two known methods. Conductometric titrations were carried out for Cu(II) and Ni(II) ions in presence or absence of the ligand to obtain association and formation constants. Crystal explorer software was used to build 3-D models for crystal packing systems according to Hirshfeld method. Strong molecular contact was ob- served for ligand models with high contribution for oxygen atom. Biological screening was elaborately handled towards microorganism, free radicals and colorectal carcinoma cell line (HCT-116). Excellent inhibition activity was clearly appeared with the ligand which sometimes exceeded reference drugs. Applying MOE, dynamic sim- ulation was executed for the ligand towards different pathogen-proteins at top scoring poses. The interaction af- finity towards protein-pockets as well as the electrostatic contour maps represent all interaction possibilities and confirm in-vitro results. © 2020 Elsevier B.V. All rights reserved. 1. Introduction Schiff bases and their transition metal ion complexes taken a great interest in last decades due to their so far advantages in various fields. Schiff bases are known by azomethine group that yielded after a simple condensation reaction between amine and aldehyde compounds [1,2]. Such bases are interesting compounds that successfully coordinating with variable metal ions through different mode of bonding [3–5]. These complexes played well particularly in biological, electrochemical and catalytic fields. Regarding the distinguish role in biological field, many complexes have been used have been implemented for cytotoxicity [6,7] and microbial [8] treatments. The biological efficiency of complexes are significantly changed from metal to another and also by changing Schiff base composition [9]. For instance, Ni(II) and Cu(II) complexes derived from Schiff bases that obtained from halogenated salicyladehyde, were appeared by versatile configurations and magnetic properties. Also, these complexes exhibited high biological activity [10]. Moreover, Schiff bases complexes have been used as a catalyst in many reactions as; electro-reduction of CO 2 [11a], epoxidation of olefins, asymmetric sulfo-oxidation [11b]. A series of new Co(II), Ni(II), Cd(II) and Cu(II) complexes were synthesized from Schiff base of 4- aminoantipyrine and displayed effective binding with calfthymus DNA [12a]. A series of HL Schiff base complexes were prepared for some M +3 ions and displayed effective biological features [12b]. Copper com- plexes were obtained from hydrazone Schiff base derivative, which used for oxidation of benzylic alcohols [13a]. Mixed ligand complexes were prepared from Cu(II) and Zn(II) ions from Schiff base ligands and successfully used to overcome prostate cancer [13b]. In chemical Journal of Molecular Liquids 319 (2020) 114116 ⁎ Corresponding author at: Department of Chemistry, Faculty of Applied Science, Umm- Al-Qura University, Makkah, Saudi Arabia. E-mail addresses: n_elmetwaly00@yahoo.com, nmmohamed@uqu.edu.sa (N.M. El-Metwaly). https://doi.org/10.1016/j.molliq.2020.114116 0167-7322/© 2020 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Journal of Molecular Liquids journal homepage: www.elsevier.com/locate/molliq