Synthesis and Characterization of Nanometric Pure Phase SnO2 Obtained from Pyrolysis of Diorganotin(IV) Derivatives of Macrocycles

Thermal decomposition of diorganotin(IV) derivatives of macrocycles of general formula, R2Sn(L1) and R2Sn(L2) (where R = n-butyl (1/4), methyl (2/5), and phenyl (3/6); H2L1 = 5,12-dioxa-7,14-dimethyl-1,4,8,11-tetraazacyclotetradeca-1,8-diene and H2L2 = 6,14-dioxa-8,16-dimethyl-1,5,9,13-tetraazacyclotetradeca-1,9-diene), provides a simple route to prepare nanometric SnO2 particles. X-ray line broadening shows that the particle size varies in the range of 36–57 nm. The particle size of SnO2 obtained by pyrolysis of 3 and 5 is in the range of 5–20 nm as determined by transmission electron microscope (TEM). The surface morphology of SnO2 particles was determined by scanning electron microscopy (SEM). Mathematical analysis of thermogravimetric analysis (TGA) data shows that the first step of decomposition of compound 4 follows first-order kinetics. The energy of activation (), preexponential factor (A), entropy of activation (), free energy of activation (), and enthalpy of activation () of the first step of decomposition have also been calculated. Me2Sn(L2) and Ph2Sn(L1) are the best precursors among the studied diorganotin(IV) derivatives of macrocycles for the production of nanometric SnO2.