Calorimetric investigation of the polymerization of organobi- and organotricyclosiloxanes

Synthesis and Properties of Phenylsilsesquioxanes with Ladder and Double-Decker Structures

“…At the stage of purification, we observed compounds with silanol groups; thus the generation To compare the spectral and thermal properties of 1−3, hexaphenyldisiloxane, hexaphenylcyclotrisiloxane, octaphenylcyclotetrasiloxane, and octaphenylsilsesquioxane were synthesized according to known procedures. 32−34 The values from 29 Si NMR are summarized in Table 1.…”

“…From these results, the chemical shifts in the 29 Si NMR can be estimated on the basis of ring size and the number of oxygen atoms bonded to silicon atoms. For example, the D (connected to two oxygen atoms) silicon atom in six-membered rings shows a peak between −32 and −34 ppm, regardless of the other molecule components.…”

“…Thus, silicon atoms contained in eight-membered rings show peaks in the Table 1. 29 Si NMR Data of Phenyl Siloxanes (in CDCl 3 ) compound structure 29 Si NMR/ppm The results of thermogravimetric (TG) analysis in N 2 are summarized in Table 2. The results show that a higher Td 5 (5% weight loss) temperature was observed with a higher inorganic component ratio (Si and O, % ratio).…”

“…The Fourier transform nuclear magnetic resonance (NMR) spectra were obtained using a Jeol ECS-300 ( 1 H at 300.53 MHz, 13 C at 75.57 MHz, and 29 Si at 59.71 MHz) NMR instrument. Chemical shifts are reported as δ units (ppm) relative to SiMe 4 , and the residual solvents peaks were used as standards.…”

“…Brown and co-workers first proposed the structure of ladder polysilsesquioxanes for phenyl-substituted ladder silsesquioxanes; however, only a few compounds were unequivocally determined by crystallographic analysis. Andrianov and co-workers reported the synthesis and structure determination of tricyclic ladder siloxanes. − Additionally, the structures of ladder siloxanes containing phenyl groups have been, in part, established. ,,,, …”