New energetic Silver(I) complexes with Nnn type Pyrazolylpyridine ligands and oxidizing anions

Abstract

The high energy complexes [Ag (pp) (NO3)] (I), [Ag (dmpp) (NO3)] (II), [Ag (pp)ClO3)] (III), [Ag (dmpp) (ClO3)] (IV), [Ag (pp) (ClO4)] (V), [Ag (dmpp) (ClO4)] (VI) were synthesized from the ligands, Bis-2,6(Pyrazol-1-yl)Pyridine (pp) and Bis-2,6 (3,5-dimethylpyrazol-1-yl)Pyridine (dmpp). They were characterized via IR spectroscopy and elemental analysis. Suitable single crystals of complexes I, IV and VI have been obtained and their molecular structures were determined by X-Ray diffraction methods. the X-Ray study revealed that these complexes were di-nuclear. All complexes have been analyzed by TG-DTA. It was determined that they decompose exothermically in explosive reactions. Elevation in the thermal decomposition temperature, enthalpy of reaction and mass loss was observed with increasing number of oxygens within the anion in the complex structure. the HOMO and LUMO energy levels of the complexes, together with the theoretical formation enthalpies, were calculated by using Gaussian 09 software package whereas the enthalpies of thermal decomposition were measured by DSC. the products of decomposition were predicted from the theoretical formation enthalpy and the measured heat of reaction values according to Hess' law. It was observed that the thermogravimetry plots of complexes I, II and VI were suitable for thermo-kinetics investigation. Thus, they were analyzed by means of isothermal (Coats-Redfern) and non-isothermal-isoconvertional (Flyn-Ozawa-Wall and Kissinger-Akahira-Sunose) methods and certain thermodynamic parameters were calculated. It was discovered that all complexes except complex II decomposed with rapid, single step reactions whereas complex II decomposed with a 2-step reaction. (C) 2020 Elsevier B.V. All rights reserved.