Synthesis and Non-linear Optical(NLO) Properties of a Series of Alkoxysilane Derivative Chromophores

1 Introduction Nonlinear optical materials（NLO） have drawn a great intrest of some scholars and scientists in the last dacades because of their tremendous potential application in optoelectronic. The fabrication of efficient optoelectron devices is a challenging task because such systems need to meet the stringentable requirements for high optical quality and large and sustainable electro-optical（EO） response. In pursuit of NLO materials with excellent optoelectronic property,

Synthesis of Alkoxysilanes Bearing β-Diketone Group through Hydrosilylation

Alkoxysilane bearing diketone group was synthesized by hydrosilylation of 3-allyl acetylacetone. It was indicated by the 1H NMR spectrum that the C=O group does not interfere with the synthesis.

SYNTHESIS AND OPTICAL PROPERTIES OF A NOVEL ORGANIC/INORGANIC HYBRID NONLINEAR OPTICAL POLYMER VIA SOL-GEL PROCESS

A new organic/inorganic hybrid nonlinear optical (NLO) material was developed by the sol-gel process of an alkoxysilane dye with tetraethoxysilane. A NLO moiety based on 4-nitro-4 ' -hydroxy azobenzene was covalently bonded to the triethoxysilane derivative, i.e, gamma -isocyanatopropyl triethoxysilane. The preparation process and properties of the sol-gel derived NLO polymer were studied and characterized by SEM, FTIR,H-1-NMR, UV-Vis, DSC and second harmonic generation (SHG) measurement. The results indicated that the chemical bonding of the chromophores to the inorganic SiO2 networks induces low dipole alignment relaxation and preferable orientational stability. The SHG measurements also showed that the bonded polymer film containing 75 wt% of the akoxysilane dye has a high electro-optic coefficient (r(33)) of 7.1 pm/V at 1.1 mum wavelength, and exhibit good SHG stability, the r(33) values can maintain about 92.7% of its initial value at room temperature for 90 days, and can maintain about 59.3% at 100 degreesC for 300 min.

Economic route to sodium-containing silicate bioactive glass scaffold

Tetraethyl orthosilicate (TEOS) and trimethyl orthosilicate (TMOS) alkoxysilanes are expensive common precursors for silicate based solgel derived bioactive glasses. Facile approa- ches involving low cost substitutes are a necessity for bioactive glass implants in bone regeneration therapy. Quaternary SiO2–Na2O–CaO– P2O5 bioactive glass was prepared by the solgel method from locally sourced sand as precursor. The monolith glass material obtained was subjected to immersion studies in simulated body fluid (SBF) for 21 days. The surface morphology and composition of the glass before and after immersion in SBF was studied using SEM-EDX, while pH analysis was used to monitor changes on the glass surface in SBF solution. FTIR was used to confirm apatite formation on the material. Results showed that the concentration of Ca, P and C increased on the surface of the glass sample as immersion time increased, which was attributed to the formation of carbonated hydroxyapatite (HCA). The material shows ability to bond to bone making it a promising scaffold material for bone repair.

Low Density Wood Impregnation with Water-Repellent Organosilicic Compounds

Many protective treatments for low density wood are applied by impregnation to give waterrepellency and to control pathologies that usually have this substrate. The properties of Araucaria angustifolia, chemically modified by impregnation with methyltriethoxysilane, n-octyltriethoxysilane and mixtures of both in several ratios, were investigated to achieve mainly high dimensional stability, low capillary water absorption as well as satisfactory water vapor permeability. The aforementioned impregnants produce the wood chemical modification, involving the reaction of hydroxyl groups of the wood with the hydrolysis products of alcoxysilanes. It is concluded that the organosilicon polymers allow improving important characteristics of wood: 1) the non-occlusive coating keeps the water vapor permeability unaltered;2) the alkoxysilane type defines the hydrophobicity and the continuity of coating formed on the pore wall and finally;3) the polymeric structure formed after finishing solgel process incises both on the capillary water absorption and the dimensional stability. In addition, the studied treatments have the advantage of allowing that the water vapor, which permeates through the orga-nosilicon coating placed on cell wall, can exit by hydrophobic repulsion and thus, prevent faults appearance generated by the condensed water inside of wood.

Cobalt-Catalyzed Difunctionalization of Styrenes via Ligand Relay Catalysis

Here,we report a cobalt-catalyzed sequential dehydrogenative Heck silylation/hydroamination of styrenes with hydrosilane and diazo compound to access 1-amino-2-silyl compounds with excellent regioselectivity.This difunctionalization reaction could undergo smoothly using 1 mol%catalyst loading with good functional group tolerance.Not only di-and tri-substituted hydrosilanes,but also alkoxysilane is suitable,which does explore the scope of the family of 1-amino-2-silyl compounds.The ligand relay phenomenon between neutral tridentate NNN ligand and anionic NNN ligand is observed for the first time via absorption spectral analysis in this one-pot,two-step transformations.The primary mechanism has been proposed based on the control experiments.