“…As expected, the asymmetric and symmetric C-O-C vibrations are assigned at 1105 and 1007 cm -1 theoretically for the title compound, which is in agreement with the literature [37]. For substituted cinnamic anhydrides, the C-O-C stretching modes have been reported at 1101, 1099 cm -1 (Raman), 1102, 940, 942 cm -1 (DFT) and C=C stretching modes at 1620 cm -1 (IR), 1621, 1601 cm -1 (Raman) and 1611, 1607 cm -1 (DFT) [23,24]. For 1,2,4-benzenetricarboxylic 1,2-anhydride, Arjunan et al, [38] reported In order to investigate the performance of vibrational wave numbers of the title compound, the root mean square (RMS) value between the calculated and observed wave numbers were calculated.…”