Abstract

Spectrophotometric and conductometric investigation of 5,5/-(2E,2/E)-2,2/-(ethane-1,2-diylidene)bis (hydrazine-1-yl-2-ylidene) bis (4-amino-4H-1,2,4-triazole-3-thiol) (HYT)macrocyclic ligand with Cu2+ cation

Author(s): Alireza Shams, Mohammad Shaker, Hassan Mallaekeh, Ehsan Bahramzadeh, Donya Arefi

The complexation reaction ofmacrocyclic ligand, 5,5/-(2E,2/E)-2,2/-(ethane- 1,2-diylidene) bis (hydrazine-1-yl-2-ylidene)bis (4-amino-4H-1,2,4-triazole- 3-thiol) (HYT)[1-8] with Cu2+ cation was studied in some binary mixtures of methanol (MeOH), propanol (PrOH) and dimethylformamide (DMF) at different temperatures using the conductometric method[9-14]. In additions the interaction of (HYT) with Cu2+ cation in non-aqueous solvent was studied by spectroscopic method. The stability constants of the complex was determined using a GENPLOT computer program[15]. The conductance data and Absorbance–mole ratio plots show that in all solvent systems, the stochiometric of the complex formed between (HYT) and Cu2+ cation is 1:1 (ML). The obtained results showthat the stability of (HYT)-Cucomplex is sensitive to the mixed solvents composition. The values of thermodynamic parameters (ÄGÚ, ÄHÚ and ÄSÚ) for formation of (HYT)-Cucomplex were obtained from temperature dependence of the stability constant using the VanÂ’t Hoff plots. The results show that in most cases the complex are enthalpy destabilized but entropy stabilized and the complex formation is affected by the pH, time, temperature and nature of solvent.