Ab initio/DFT calculations of tert-butyl ammonium salt of O,O 0 -dibornyl dithiophosphate H.H. Kart a,⇑ , S. Özdemir Kart a , M. Karakus ß b , M. Kurt c a Department of Physics, Pamukkale University, Kinikli, 20017 Denizli, Turkey b Department of Chemistry, Pamukkale University, Kinikli, 20017 Denizli, Turkey c Department of Physics, Ahi Evran University, 40100 Kırs ßehir, Turkey highlights  O,O 0 -dibornyl dithiophosphete has been synthesized.  The compound has been characterized by IR, 1 H and 13 C NMR spectroscopy.  DFT/B3LYP results are more compatible with the measured results. graphical abstract O,O 0 -dibornyl dithiophosphate has been synthesized by the reaction of P 2 S 5 and borneol in toluene. article info Article history: Received 7 January 2014 Received in revised form 5 March 2014 Accepted 23 March 2014 Available online 2 April 2014 Keywords: FT-IR NMR DFT and HF Dithiophosphate abstract O,O 0 -dibornyl dithiophosphate has been synthesized by the reaction of P 2 S 5 and borneol in toluene. Fourier Transform Infrared spectra (FT-IR) of the title compound are measured. The molecular geometry, vibrational frequencies, infrared intensities and NMR spectrum of the title compound in the ground state have been calculated by using the density functional theory (DFT) and ab initio Hartree–Fock (HF) methods with the basis set of 6-31G(d). The computed bond lengths and bond angles show the good agreement with the experimental data. Moreover, the vibrational frequencies are calculated and the scaled values have been compared with experimental FT-IR spectra. Assignments of the vibrational modes are made on the basis of total energy distribution (TED) calculated with scaled quantum mechan- ical (SQM) method. The observed and calculated FT-IR and NMR spectra are in good agreement with each other. Ó 2014 Elsevier B.V. All rights reserved. Introduction Dithiophosphates compounds [(RO) 2 P(S)SH] and their metal complexes are an important class in organophosphorous chemistry [1–5] due to utilizing in agricultural, medicinal and technological fields [6,7]. Dithiophosphates or O,O 0 -dialkyldithiophosphoric acids can be synthesized by the reaction of P 2 S 5 , which is commer- cially available reagent, and the corresponding alcohols. Therefore, there are many dithiophosphates in the previous reports and some of their properties have been investigated. For example, zinc-dialkyl dithiophosphate complexes (ZDDP) have been known antiwear http://dx.doi.org/10.1016/j.saa.2014.03.076 1386-1425/Ó 2014 Elsevier B.V. All rights reserved. ⇑ Corresponding author. Tel.: +90 2582963588; fax: +90 2582963535. E-mail address: hkart@pau.edu.tr (H.H. Kart). Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 129 (2014) 421–428 Contents lists available at ScienceDirect Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy journal homepage: www.elsevier.com/locate/saa