Thermal decomposition mechanism of Ba(DPM)2

Abstract

We have investigated the thermal decomposition behavior of Ba(DPM)2 using thermogravimetry (TG), mass spectrometry (MS), ultraviolet (UV) absorption and in-situ Fourier transform infrared (FTIR) spectroscopy. FTIR has been used particularly for direct monitoring of the bond dissociation order in the metal complex by thermal treatment in either N2 or O2. TG analysis shows that the ambient gas has a significant effect on the weight loss patterns of Ba(DPM)2. The chemical bonds of Ba(DPM)2 begin to decompose at low temperatures below 50 °C and are sequentially dissociated when the temperature is raised. The C-C(CH3)3 and the Ba-O bonds are decomposed most easily at low temperatures, followed by the C-H bond, but the stable C-C and C-O bonds do not dissociate until the total complex is gasified. The decomposition sequence of the chemical bonds in Ba(DPM)2 is similar to that of Sr(DPM)2 but differs from that of Ti(O-iPr)2(DPM)2 which is decomposed in the sequence of C(CH3)3 > C-H and C-O > Ti-O. The major difference in the decomposition sequence between Ba and Ti complexes can be seen to derive from the intrinsic character of the individual metal-oxygen bond as observed by UV spectroscopy.