FTIR measurements of the sample obtained in the fifth reaction step (Fig. 5) show an absorption band in 805 cm1, corresponding to the Si–C bond, as reported in the literature for this compound (Guo et al., 2001; Chung et al., 2011; Rajarao et al., 2014), and a second one in 1102 cm1, due to vibration of asymmetric stretch of the Si–O–Si bond (Ye et al., 2012).