Triethoxysilyl Propyl Isocyanate Research Articles

From chemistry to materials, design and photophysics of functional terbium molecular hybrids from assembling covalent chromophore to alkoxysilanes through hydrogen transfer addition

Two silica-based organic–inorganic hybrid materials composed of phenol (PHE) and ethyl- p-hydroxybenzoate derivatives (abbreviated as EPHBA) complexes were prepared via a sol–gel process. The active hydroxyl groups of PHE/EPHBA grafted by 3-(triethoxysilyl)-propyl isocyanate (TESPIC) through hydrogen transfer reaction were used as multi-functional bridged components, which can coordinate to Tb 3+ with carbonyl groups, strongly absorb ultraviolet and effectively transfer energy to Tb 3+ through their triplet excited state, as well as undergo polymerization or crosslinking reactions with tetraethoxysilane (TEOS), for anchoring terbium ions to the silica backbone. For comparison, two doped hybrid materials in which rare-earth complexes were just encapsulated in silica-based sol–gel matrices were also prepared. NMR, FT-IR, UV/vis absorption and luminescence spectroscopy were used to investigate the obtained hybrid materials. UV excitation in the organic component resulted in strong green emission from Tb 3+ ions due to an efficient ligand-to-metal energy transfer mechanism.

Molecular assembly and photoluminescence of novel rare earth/inorganic/polymeric hybrid materials with functional covalent linkages

In the context, organic polymeric precursor, polyethylene glycol (PEG) was firstly modified by inorganic component of 3-(triethoxysilyl)-propyl isocyanate (TEPIC) to form the inorganic/organic polymeric functional bridge precursor. Subsequently, the corresponding organic/inorganic molecular-based hybrids were assembled to behave the structural polymeric ligands with the two components equipped with covalent bonds. The coupling reagent part is a functional ureasils –NHC(=O)–O–group which is applied to coordinate to RE 3+ and further formed Si–O backbones after hydrolysis and polycondensation processes. Furthermore, aromatic carboxylic acids (picolinic acid (HPIC), 2-chlorobenzoic acid (HCBA) and salicylic acid (HSAL)) were used as functional sensitized ligands to coordinate with RE 3+(Eu 3+, Tb 3+ and Dy 3+) and resulting in the quaternary rare earth/inorganic/organic polymeric hybrid materials with chemical bond (covalent bonds of –CO–NH– and Si–O, coordination bond of RE–O–C). Luminescence spectra were utilized to characterize the photophysical properties of the obtained hybrid material and the intramolecular energy transfer process took place within these molecular-based hybrids and characteristic emissions of RE 3+ have been achieved.

Optimization of UV curable acrylated polyester-polyurethane/polysiloxane ceramer coatings using a response surface methodology

Dual UV and moisture curable acrylated polyester, organic/inorganic hybrid coatings were prepared using a coupling agent and tetraethylorthosilicate (TEOS) oligomers. An acrylated polyester resin based on adipic acid, neopentyl glycol, trimethylolpropane, and acrylic acid was synthesized. TEOS oligomers were prepared through the hydrolysis and condensation of TEOS with water and 3-(triethoxysilyl)propylisocyanate (TEOSPI) was used as the coupling agent between organic and inorganic phases. Trimethylolpropane triacrylate (TMPTA) was used as a reactive diluent. The formulations were cured into films by utilizing UV, followed by moisture curing. The resultant coatings were evaluated in terms of tensile and fracture toughness properties by using ANOVA. Effects of the TEOS oligomers, TEOSPI, and TMPTA on the free radical UV polymerization kinetics were also investigated. The experiments were planned according to the three-factor, three-level Box-Behnken design. Reaction kinetics, fracture toughness, and tensile properties were evaluated in terms of the concentrations of TEOS oligomers, TEOSPI, and TMPTA concentrations.

Terbium/zinc luminescent hybrid siloxane-oxide materials bridged by novel ureasils linkages

Covalently bonded silicate/modified aromatic acid luminescent composites have been prepared from 3-(triethoxysilyl)-propyl isocyanate (TEPIC) grafted salicylic acid and central metal ions (Tb, Zn). The existence of covalent linkages between TEPIC and silica matrices were realized by after hydrolysis and polycondensation processes of ethoxysilyl groups. Luminescence spectra were utilized to characterize the photophysical properties of the obtained hybrid material and the above spectroscopic data reveal that the triplet energy of modified salicylic acid in this favorable hybrid system matches with the emissive energy level of Tb 3+. In addition, Zn containing hybrids exhibit a broad band around 420 nm which may be beneficial to fabricate blue emission materials.

Optically hybrid lanthanide ions (Eu3+, Tb3+)-centered materials with novel functional di-urea linkages

The synthesis of 3-(triethoxysilyl)-propyl isocyanate (TEPIC) modified by (3-aminopropyl)triethoxysilane (APS) and the preparation of the corresponding organic–inorganic molecular-based hybrid material with the two components equipped with covalent bonds is described. The coupling agent moiety is a convolution of TEPIC and APS through NHC(O)NH groups, which is applied to coordinate to RE3+ and further formed SiO backbones after hydrolysis and polycondensation processes. For comparison and luminescence efficiency purposes, we added 2,2-bipyridyl to the above hybrids in order to increase the conjugating effects and sensitize rare earth ions emissions. Luminescence spectra were utilized to characterize the photophysical properties of the hybrid material obtained, and the above spectroscopic data reveal that the triplet energy of 2,2-dipyridyl in this favorable hybrid system matches with the emissive energy level of RE3+. In this way, the intramolecular energy transfer process took place within these molecular-based hybrids and strong green and red emissions of RE3+ have been achieved. Copyright © 2005 John Wiley & Sons, Ltd.

Synthesis of covalently bonded cellulose derivative chiral stationary phases with a bifunctional reagent of 3-(triethoxysilyl)propyl isocyanate

A bifunctional reagent of 3-(triethoxysilyl)propyl isocyanate (TEPI) was initially adopted as a spacer reagent to prepare the bonded types of chiral stationary phases (CSPs) with cellulose derivatives. The silica-based CSPs were chemically prepared with non-regioselective and regioselective approaches and their chiral resolving capabilities were evaluated in terms of HPLC resolution of test enantiomers. It was observed that the chiral recognition capabilities of the non-regioselectively prepared CSPs were influenced by the amount of TEPI used. And also, the regioselectively prepared CSP generally showed a slightly higher resolution power than the non-regioselectively prepared CSP, while the non-regioselective procedures were highly advantageous to rapid preparation. In addition, chiral recognition of the prepared CSPs was affected by the properties of the used silica matrices.

Surface characterization of a potential photoactive LC coupling agent

Azo dye molecules were grafted onto a silicon wafer surface in order to generate a potentially orienting substrate interface for liquid–crystal (LC) layers. This coupling agent was synthesized by reaction between 4-[bis(2-hydroxyethyl)amino]-4′-nitro azobenzene (DR19) and 3-(triethoxysilyl)propyl isocyanate (TESPI). The 1H-NMR, IR spectra of the silylated compound confirmed that nucleophilic addition between the carbonyl group of TESPI and the hydroxyl functions of DR19 had occurred. In this article, the silanization conditions are described and the thin layers obtained characterized using Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and X-ray reflectivity.