Synthesis of thiadiamidocrown ethers and a thermodynamic study of their complexation with some metal ions using DFT calculations and conductometric method in acetonitrile

• Published in: Journal of sulfur chemistry 2023-09, Vol.44 (5), p.573-587
• Main Authors: Ashram, Muhammad, Mizyed, Shehadeh A., Rawashdeh, Abdel Monem, Al-Rbaihat, Mohammad R.
• Format: Article
• Language: English
• Subjects: Acetonitrile; Complex formation; Complexation; Conductivity; Crown ethers; Ions; Lead; Mass spectrometry; Mathematical analysis; metal ions; NMR; Nuclear magnetic resonance; Stability; Stability constants; thermodynamic; Thermodynamics; thiadiamidocrown ethers
• ISSN: 1741-5993; 1741-6000
• DOI: 10.1080/17415993.2023.2202797

Three new thiadiamidocrown ethers 1-3 have been synthesized and characterized by 1 H-NMR, 13 C-NMR and mass spectrometry. A thermodynamic study of the complexation of compounds 1-5 with metal cations (M n+ ); Pb 2+ with 1, 2, 4, and 5; Ag + with 1, 2, and 3 and Hg 2+ with 2 in acetonitrile, has been carried out at 288-308 K using a conductometric technique. The observed molar conductivity of the metal salts solutions, ⋀, was found to decrease upon addition of crown ethers solutions and tend to level off near the mole ratios [L] T /[M] T of unity. The ΔH° and ΔS° values for the complexation reactions were evaluated from the slopes and intercepts of the van't Hoff plots, respectively. The results show that the stability constants of Pb 2+ complexes at 25 °C vary as: 5 > 4 > 2 > 1 while the stability constants of Ag + complexes vary as: 3 > 2 > 1. ΔG° values for all complexes have negative values indicating a spontaneous complex formation process. A theoretical calculations using DFT which was conducted on the above systems gave results that supported the experimental results in most of the cases.