Study based on docking of antimicrobial activity and fluorescence behavior of ammonium salt of diisopropyl dithiophosphate, O,O′- diisopropanediyl S-(N-phthalimido methyl) and zinc diisopropyl dithiophosphates

Abstract

The ammonium salt of diisopropyl dithiophosphate (A1), O,O′- diisopropanediyl S-(N-phthalimido methyl) dithiophosphate (L1) and zinc diisopropyl dithiophosphate (L2) were isolated in non-aqueous medium and well-characterized by UV–visible spectroscopy, infrared (IR) spectroscopy, NMR (¹H, ¹³C and ³¹P) spectra and single-crystal X-ray diffraction analysis. The isopropyl group attached to the metal in compound L2 functions as the inter- and intra-chelating group which deviate slightly from planarity with the metal atoms. The central eight-membered ring possesses the “cradle” configuration. The fluorescence spectra of the three compounds A1, L1 and L2 were compared and it was observed that derivatives show excitation due to electron-donor and -acceptor groups. The intramolecular charge transfer (ICT) occurs from P = S to one of the C = O groups in the phthalimide ring and thiophosphate when these molecules are excited electronically in a polar solvent and, therefore, ICT state displays a fluorescence property. The molecular docking study was also carried out for the three compounds. Based on docking studies, a zinc-based metal complex of isopropyl dithiophosphate showed good antifungal activity whereas phthalimide-based isopropyl dithiophosphate derivative showed better antibacterial activity.

Graphical Abstract

Keywords:

• Antifungal activity
• docking study
• fluorescence
• phthalimide
• thermal analysis

Supplementary material

Crystallographic data (CIF) for the structures reported in this article have been deposited with the Cambridge Crystallographic Data Center and allocated the deposition number CCDC 1864030 of L1 and 1864031 of A1. These data can be obtained, free of charge via www.ccdc.cam.ac.uk/data_request/cif, by sending an e-mail to [email protected]., from the Cambridge Crystallographic Data Center, 12, Union Road, Cambridge CB2 1EZ, UK: fax: [phone].

Acknowledgments

R.R. is grateful to MPCST Project, Bhopal (Endt No. 1045/CST/R&D/2012) for financial assistance and to my loving mother for her continuous support. The authors are thankful to SAIF Chandigarh, India, for ESI MS, ¹H, ¹³C, and³¹P NMR spectra, respectively, and STIC, Cochin, India, for elemental analysis. The authors are also thankful to the Dean Research, Department of Physics, ITM University, Gwalior, India, for IR measurements. Crystallographic studies were supported in Naval Research Laboratory, USA. R.J.B. acknowledges Dr. Jan Wikaira and the University of Canterbury for access to their diffractometer.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The study was funded by MPCST Project, Bhopal (Endt No. 1045/CST/R&D/2012).