Abstract

Kavita S. Mundhe*, Nirmala R. Deshpande and Rajashree V. Kashalkar

ABSTRACT

X- ray crystallography is an important modern technique for determination of structure of a molecule. 5, 5- dimethylcyclohexane 1, 3-dione and its derivatives are synthesized. Single crystal of synthesized compound has been studied by X-ray crystallography. Oak Ridge Thermal Elipsoid Plot (ORTEP), Crystal data and structure refinement for compound shows that molecules are inter molecularly hydrogen bonded with hydrogen atom of NH group. A linear chain of molecules is formed via N-H…O hydrogen bonding with x y z…x 1+y z and N…O while the distance noticed is 2.865 Å. Thermogravimetric analysis (TGA) of synthesized compounds has been performed to obtain order of reaction and energy of activation which will be helpful in determining the biological potentials. Thermo gravimetric analysis of almost all synthesized compounds indicates that all molecules decompose in two steps. The first step starts around 950c to 350 0c and the second step extends from 267 0C to 657 0C. Compound 5 decomposes in three stages which correspond to 710C to 1060C, 106 0C to 2180C and 2180C to 5060C. It is very clear from the results that all molecules have order of reaction (?) of 0.8.The calculated energy of activation indicates an increase in Ea from first stage to second stage for all compounds except compound 5. The energy of activation (Ea) is very high (13.85 kJ) during first stage. It decreases to 6.59 KJ for second stage; while a significant increase (9.87 KJ) is noticed during third stage of compound 5.