FULL PAPER Investigation of pharmacophore and antipharmacophore features of certain dimethyltin(IV) complexes of flexible N‐protected amino acids and fluorinated β‐diketone/β‐diketones Karuna Maheshwari | Manish Kumar Srivastava | Sanjiv Saxena | Asha Jain * Department of Chemistry, University of Rajasthan, Jaipur, Rajasthan, India Correspondence Asha Jain, Department of Chemistry, University of Rajasthan, Jaipur, Rajasthan, India. Email: aashajain27@gmail.com A set of pentacoordinated dimethyltin(IV) complexes of flexible N‐protected amino acids and fluorinated β‐diketone/β‐diketones was screened for their antibacterial activity against Pseudomonas aeruginosa, Staphylococcus aureus and Streptomyces griseus. These pentacoordinated complexes of the type Me 2 SnAB (where : R = CH(CH 3 )C 2 H 5 ,A 1 H; CH 2 CH(CH 3 ) 2 , A 2 H; CH(CH 3 ) 2 ,A 3 H; CH 2 C 6 H 5 ,A 4 H; and BH = R'C(O)CH 2 C(O)R″:R′ =C 6 H 5 , R″ = CF 3 ,B 1 H; R′ =R″ = CH 3 ,B 2 H; R′ =C 6 H 5 ,R″ = CH 3 ,B 3 H; R′ =R″ =C 6 H 5 , B 4 H) were generated by the reactions of dimethyltin(IV) dichloride with sodium salts of flexible N‐protected amino acids (ANa) and fluorinated β‐ diketone/β‐diketones (BNa) in 1:1:1 molar ratio in refluxing dry benzene solution. Plausible structures of these complexes were elucidated on the basis of physicochem- ical and spectral studies. 119 Sn NMR spectral data revealed the presence of pentacoordinated tin centres in these dimethyltin(IV) complexes. KEYWORDS antibacterial activity, dimethyltin(IV) complexes, N‐protected amino acids, pharmacophores, β‐diketones 1 | INTRODUCTION The last few decades have witnessed important developments regarding the characterization of chemical structure based on spectroscopic studies. [1–3] The chemical structure of a drug molecule may be related to its physiological action. The structure–activity relationship of organotin complexes is an important concept which correlates some structural aspects of organotin(IV) complexes with their biological and toxico- logical properties. [4–6] The chemistry of organotin(IV) com- plexes is a prolific and active area of research as these complexes find applications in agriculture, [7,8] medicine [7] and industry. [7,8] Some organotin(IV) complexes are used as antifouling agents, [9] as catalysts, [10,11] as precursors of SnO 2 [12] and as wood preservatives. [13,14] A number of organotin(IV) complexes are extensively used as anti‐inflam- matory, [15,16] cardiovascular, [15] insecticidal, [6,17] antifun- gal, [17] antibacterial [18–23] and antitumor agents. [24–27] The bioactivity of organotin(IV) complexes is affected by the nature and number of organic groups, the nature of donor atoms attached to tin and the coordination number of tin. In order to investigate the pharmacophore and antipharmacophore features of some pentacoordinated dimethyltin(IV) complexes, the reactions of dimethyltin(IV) dichloride with sodium salts of flexible N‐protected amino acids and fluorinated β‐diketone/β‐diketones were carried out which resulted in the formation of pentacoordinated dimethyltin(IV) complexes. It is interesting to correlate the structures of these pentacoordinated dimethyltin(IV) com- plexes with their pharmacophore and antipharmacophore properties (activities) which may be useful in the field of drug design. 2 | EXPERIMENTAL Stringent precautions were taken to remove atmospheric moisture while carrying out experimental work. β‐Diketones, Received: 27 February 2016 Revised: 15 June 2016 Accepted: 1 July 2016 DOI 10.1002/aoc.3570 Appl. Organometal. Chem. 2016; 1–10 Copyright © 2016 John Wiley & Sons, Ltd. wileyonlinelibrary.com/journal/aoc 1