Poly(silsesquioxanes) derived from the hydrolytic condensation of organotrialkoxysilanes containing hydroxyl groups

Architecture of Silsesquioxanes

“…Fasce et al reported similar considerations on cage-type silsesquioxanes with 8, 9, and 10 Si atoms, obtained by the hydrolytic condensation of triethoxysilanes with bulky organic substituents (Fasce et al 1999(Fasce et al , 2001. The presence of (β-hydroxyl) tertiary amine functions in the bulky organic group of the pristine organosilane favored the formation of closed structures (Dell'Erba et al 2003;Fasce et al 2005). Steric demand of the organic group and distance between the hydroxyl and tertiary amino group were assumed to influence the internal cyclization ability, avoiding gelation and resulting in nano-objects (Mori et al 2007).…”

“…1) is largely influenced by the organic group R in the pristine organosilane, in particular the formation of cage or ladder structures depending on both steric and electronic effects promoting intramolecular condensation to a different extent (Dell'Erba et al 2003;Pescarmona and Maschmeyer 2001). Bulky R groups like methacryloxypropyl, glycidyloxypropyl, and aminopropyl promote intramolecular condensation favoring cage formation (Eisenberg et al 2000) but cyclohexyl (Feher et al 1989) and cyclopentyl (Feher et al 1991) groups favor the formation of incompletely condensed silsesquioxanes.…”

UV-Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis of synthetic polymers by using nor-harmane as matrix

“…2,3,4,7,8,10,11 Pyridoindole compounds such as commercial β-carbolines (9H-pyrido [3,4-b]indoles) have been reported as useful matrices for proteins, 12-15 sulfated carbohydrates 12,13,[15][16][17][18] and some non-commercial synthetic polymers (polyesters, polyamides and silesquioxanes). [19][20][21][22][23][24][25] Mercaptobenzothiazoles have also been reported as useful matrices for synthetic polymers. 5 It is interesting to point out that, although the dependence on wavelength of the laser source has been taken into account, [26][27][28][29] little attention has been paid to the chemical structure (functional groups or geometry) and photochemical properties of potential matrix compounds.…”

“…Low-soluble and nonsoluble polymers are generally not analyzable by UV-MALDI although the successful use of DMSO in the analysis of chiral polyhydroxy polyamides and the details for the sample preparation method has been described. 20 Nor-harmane has been shown to be a good UV-MALDI matrix for the analysis of a wide variety of non-commercial synthetic polymers [19][20][21][22][23][24][25] and bio-macromolecules, 6,9,12,13,16,17 In the present study commercially available synthetic polymers such as PEG, PMMA, PS and poly(dimethyl)siloxane (PDMS) have been selected for UV-MALDI analysis with nor-harmane. These experiments have been conducted in positive and negative ion modes and the efficiency of the desorption/ionization processes, with and without ionizing salt, have been compared.…”

“…Recently we have described the UV-MALDI analysis of four families of new polysilsesquioxanes whose oligomers structure could be assigned. [21][22][23][24][25] In these papers we only described in detail the spectra obtained in positive ion mode, and results of similar quality were obtained with various matrices i.e. GA, IAA, HABA and nor-harmane.…”