Rodinel Ardeleanu

Si-H functional polysilanes via a homogeneous reductive coupling reaction

A polysilane copolymer with reactive Si-H side groups was obtained through a homogeeous coupling reaction of dichlorodiphenylsilane with dichloromethylsilane. The reaction was carried out in a tetrahydrofuran (THF) solution of a sodium-potasium alloy complex with 18-crown-6 with a well defined composition of alkali metal ion pairs (Mt + /crown ether, Mt ― ) at -75°C. The product was characterized using 1 H NMR, 13 C NMR, FT-IR and UV/Visible spectroscopies and gel permeation chromatography. The result were compared with those obtained by the heterogeneous coupling reaction of the same monomers.

Synthesis of polysilane–bis(salicyliden)ethylenediamine Ni(II) complex

Abstract This paper describes the synthesis of a new coordination polymer prepared through the polycondensation reaction of α,ω-bis(chloromethyl)-polymethylphenylsilane with the Ni(II) complex of bis(salicylidene)ethylenediamine (salen). For this purpose, a new preparation method of the chloromethylated polysilane was presented along with the synthesis and characterisation of the polymer–metal complex. IR, 1 H-NMR and UV–Vis spectral analyses as well as GPC and TGA were used to investigate the new chemical structures.

Detection of toluene dissolved in water by using PCS fibers excited by an inclined collimated beam

This paper reports results on the sensitivity of straight polymer-clad silica (PCS) detection fibers with short sensing parts coated with polysiloxane polymers to toluene dissolved in water. The detection was based on refractive index changes of the polymers induced by the penetration of toluene into them. These changes were detected by measuring changes of the output power from the detection fibers excited by an inclined collimated beam at 630 nm. Commercially available Cablelite 950-701 and two types of polymethylphenylsiloxane polymers developed at the Romanian Academy were tested as materials for the fabrication of the detection part in the fiber cladding. These parts were prepared by application of polymer layers onto a bare silica core by a dip-coating technique. Layers with thicknesses of about 20 mm were prepared. Examples of angular distributions of the output power determined for the detection polymers in contact with air, time response curves measured with the detection parts brought into contact with aqueous solutions of toluene under different hydrodynamic conditions, and sensitivity curves are shown in the paper. The best detection limit of about 10 mg/l of toluene, reversibility and linearity of the fiber response in a range 0‐100 mg/l could be achieved with fibers coated with Cablelite 950-701 polymer. # 2003 Elsevier Science B.V. All rights reserved.

Polyhydrosilanes I. Synthesis

Abstract Using the well known Wurtz coupling technique, polyhydrosilanes copolymers with diphenyl - and methyl(phenyl) - sequences, were synthesised. This work describes the possibility to maintain stable Si-H group and to obtain in good yields, soluble, high molecular, functional polysilanes. IR, 1-NMR, 13C, UV spectral data, quantitative elemental Si and H (from Si-H) analyses and indirect molecular weight investigation sustain the molecular structure of the copolysilanes.

Photosensitive crown ether-siloxane copolymers bearing azobenzene chromophores

This paper presents the synthesis procedure of new photosensitive siloxane–crown ether copolymers using the polycondensation reaction of an oligosiloxane with COCl end groups and bisazo derivatives of dibenzo-18-crown-6 polyether. The azodiphenol compounds were prepared via the coupling reaction of 4,4 0 -diamine-DB18C6 diazonium salt with phenol or 1-naphthol. The polymers were characterized by IR absorption and 1 H-NMR spectra as well as by thermal analysis and GPC. A study of the photoisomerization process as well as the thermal relaxation of azoaromatic chromophores in the polysiloxane–crown ether copolymer in dimethyl sulfoxide solution and of the corresponding complexes with KSCN was also presented. 2002 Elsevier Science Ltd. All rights reserved.

Polysilane—Metal Complexes for Organic Semiconductors

New polysilane-metal complexes structures were obtained by the polycondensation reaction of α,ω-bis(chloromethyl)-polymethylphenylsilane with the Ni (II) complex of bis(salicylidene)ethylenedia-mine (salen). The chloro-functionalized polysilane was obtained by a modified Wurtz coupling procedure at low temperatures. To obtain the polymer-metal complex the resulted macroligand was complexed with metal cations. This structure is characterized by a highly localized electroactivitry in the redox moiety combined with a specific σ conjugative effect in the polysilane chain. Infrared, 1H NMR and UV-vis spectral analysis as well as gel permeation chromatography and thermogravimetric analysis were used to investigate the new chemical structures.

Synthesis and Characterization of Polysilane-Organometallic Complexes

A new polysilane with pendant metal complex segments was synthesized and characterized. For this purpose a macroligand has been prepared starting from a iodopropyl-functionalized polysilane and a bis(salicylideneimine) derivative. Under mild reaction temperature this polymeric ligand was able to form crosslinked structures. The material was then doped with metal cations and was investigated to observe the system behavior near the gelation point. The UV-vis spectrum of the new material indicated that the electronic structures of the conjugate polysilane chain and metal complex remained unaffected by the condensation reaction process. Similar polymeric structures could be useful to build new organic electroconductive devices.

Polydiphenylsilanes bearing photosensitive azocrown groups

This work presents the synthesis and particularities of the reversible trans-cis UV light induced photoisomerization process of a polydiphenylsilane bearing (propyl-oxyphenylazo)dibenzo-18-crown-6 side groups.

Synthesis of Polysiloxaneimide with Piezoelectric Response

A new segmented polysiloxaneimide was synthesized by solution polycondensation of N, N bis(hydroxyethyl)benzophenontetracarboxylic diimide with siloxane diacid chloride. The copolymer was obtained with good yield and high molecular weight. The characterization by IR and 1H-NMR spectrometry and a study of the properties such as solubility and thermal behaviour of this copolymer are presented. A corona poling study was performed to obtain information about the piezoelectric behaviour of polysiloxaneimide. The remanent dielectric constants of the polarized samples were compared with those of well-known piezoelectric polymers.

Siloxane Copolymers Containing Crown Ethers

Abstract Functional siloxane copolymers containing crown ethers were synthesized through the polycondensation reaction of α,ω-hydroxypropylsiloxane oligomers with bis-(4′-chioroformyl)-dibenzo-18-crown-6, in solution. The compounds were characterized using IR, 1H-NMR spectrophotometry and by elemental C, H, and Si analysis. All data agree with the proposed structures.