Binulcear polyunsaturated organosilicon dendrimers

Binuclear polyunsaturated organosilicon dendrimers of the zero and first generations, whose central silicon atoms are linked by-CH₂-Ch₂-,-CH=CH-, or-C≡C-bridges, and also containing internal (C≡C) and (CH=CH) groups are prepared. NMR spectra of all the compounds obtained are studied. Their molecular weights were calculated and evaluated experimentally. Key parameters of new dendrimers are presented.     

Three branch polyunsaturated organosilicon and organogermanium dendrimers

3-Branch dendrimers of the first generation possessing at the focal point, the silicon atom, a trimethylsilylvinyl or trimethylsilylethynyl group, and at the central germanium atom an isopropyl group have been synthesized using a combined approach or a convergent reaction scheme. NMR spectra of all synthesized compounds are studied, and their molecular masses are calculated and experimentally determined. The key parameters of new dendrimers are given.     

New polyunsaturated organosilicon dendrimers based on 1,1-diethynyl-and 1-vinyl-1-ethynylsilacycloalkanes

1,1-Dichloro-and 1-vinyl-1-chlorosilacyclanes were prepared by reactions of tetrachlorosilane or vinyltrichlorosilane with magnesium and 1,4-dibromobutane or 1,5-dibromopentane. The reactions of the products obtained with ethynylmagnesium bromide or bis(bromomagnesio)acetylene yield the corresponding ethynylsilacyclanes. Condensation of 1,1-diethynylsilacyclanes or bis(ethynylsilacyclopentyl)ethyne with an equimolar amount of ethylmagnesium bromide and methylbis(trimethylsilylethynyl)fluorosilane gave the corresponding highly unsaturated mono-and binuclear first-generation dendrimers with the cores formed by the silicon atoms incorporated in silacycloalkane fragments. The ¹H, ¹³C, and ²⁹Si NMR spectra of all the compounds obtained were studied. The key parameters and the chemical graph of the new dendrimers are presented.     

Spherical polyunsaturated organosilicon and organogermanium first generation dendrimers of regular structure

Synthesis of the mononuclear organosilicon tri-and tetradendrones of the first generation with the repeating CΞC groups as well as the synthones for their construction is carried out. The tetrabranched polyunsaturated dendrimers G1 having regular structure of containing silicon and germanium atoms simultameously are synthesized. The IR and NMR spectra of all the compounds obtained are studied, and molecular masses of the compounds are calculated and evaluated experimentally. Key parameters and chemical graphs of new dendrimers are presented.     

Mononuclear polyunsaturated organosilicon dendrimers simultaneously containing (CH=CH) and (C≡C) fragments

Mononuclear organosilicon tri- and tetradendrons of the zero, first, and second generations, containing double bonds in the internal near-core molecular sphere, internal C≡C groups, and terminal Me, CH=CHSiMe₃, and C≡CH substituents at the central silicon atom were synthesized. Their IR and ¹H, ¹³C, ²⁹Si NMR spectra were studied. The molecular weights of the dendrimers obtained were evaluated, and key parameters of these compounds are presented.     

From the discovery of sodiumoxyorganoalkoxysilanes to the organosilicon dendrimers and back

Upon being discovered 20 years ago, sodiumoxyorganoalkoxysilanes became the key to the world of organoelement dendrimers. Even considering the great variety of objects that had appeared in this area during the last 20 years, the organosilicon dendrimers are still one of the most actual objects in this class. Above all, this is fair concerning the carbosilane systems. The high reactivity of the functional groups, the well controlled chemistry of their transformations, and the inertness of the molecular skeleton are the reason for making these systems highly actual in two main regards: as model objects for the deep research of the dendrimers' properties and as polyfunctional matrixes for numerous derivatives. In this review, we were mainly focusing on the importance of the former part. In the conclusion, we showed the motivation for further development of this area both in regard of synthesis of new carbosilane systems and further development of siloxane dendrimers. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4935–4948, 2008     

New sparse polymethylsiloxane dendrimers

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New polyunsaturated silahydrocarbons

12-Membered highly unsaturated macrocyclic silahydrocarbon containing exocyclic methyl and benzyl groups is synthesized by the reaction of benzylmethyldi(bromomagnesiumethynyl)silane with dimethyldichlorosilane. Hydrosilylation of benzyl(triethynyl)silane with trichlorosilane with subsequent reaction of the formed adduct with trimethylsilylmagnesium bromide leads to the spherical dendrimer (N_C = 3) containing the benzyl group at the central Si atom, -CH=CH- groups in the inner sphere and numerous triple bonds on periphery. NMR spectra of the obtained compounds were studied.     

Synthesis and investigation of organosilicon dendrimers based on octavinylsilsesquioxane and sulfenyl chlorides of metal acetylacetonates

The addition of sulfenyl chlorides of metal acetylacetonates to octavinylsilsesquioxane was studied. The addition was shown to proceed at four of the eight vinyl groups of the octavinylsilsesquioxane, without the formation of cross-linked polymers. This allowed us to synthesize with high yields new non-functianalized and functianalized dendrimers based on octavinylsilsesquioxane and the sulfenyl chlorides of metal acetylacetonates.     

New sorbents based on organosilicon guanidine derivatives

Monomeric and polymeric organosilicon derivatives of 1-acetylguanidine, which exhibits sorption properties, were synthesized. The organosilicon polymers prepared were studied as sorbents for heavy [Hg(II)] and noble [Ag(I), Au(III), Rh(III), Pd(II), Pt(IV)] metals. They actively take up platinum group metals and exhibit metallochromic properties by analogy with the starting compound, 1-acetylguanidine. Their interaction with all the elements studied is accompanied by coloration. The initial monomers exhibit similar metallochromic properties.     

New complex macromolecular architectures based on organosilicon chemistry

Polycarbosilane networks were prepared from well-defined α, ω-difunctional oligomers: X-[Si(CH₃)₂-CH₂-CH₂]_n-X with X = H ( 1 ) and X = CH=CH₂ ( 2 ). Crosslinking reactions were performed by hydrosilylation of tetramethyltetravinylcyclotetrasiloxane (V₄) or of tetravinylsilane with SiH end groups of 1 . Hydrosilylation of Si-CH=CH₂ end groups of 2 with tetramethyltetrahydrocyclotetrasiloxane (D₄H) was also successfully tried. Some physicochemical properties of these new networks will be presented.¹⁾ Interpenetrating networks based on polysiloxanes and polycarbonates were synthesized by the in situ method: a polysiloxane bearing various proportions of room temperature crosslinkable -Si(OEt)₃ side groups was mixed with bis(allyl ethylene glycol) biscarbonate and a free-radical initiator. After the formation of the first network at room temperature, the cross-linking of the polycarbonate network was performed by raising the temperature up to 80°C. Various chemical modifications of the polysiloxane component in the IPN were performed in order to improve the degree of interpenetration as estimated from turbidity, density, refractive index and DSC measurements.²⁾     

New phosphorus-containing dendrimers with ferrocenyl units in each layer

New phosphorus-containing dendrimers bearing ferrocenyl units within the branches were synthesised using a new 1,1’-disubstituted ferrocenyl building block. The structure of one of the synthetic intermediates was determined by X-ray analysis. In every case, one single oxidation was observed for each ferrocenic layer, corresponding to the independent oxidation of all ferrocenes within one layer to ferroceniums. The oxidation potential for a particular layer depends on substituents on ferrocenes, but not on their localisation within the dendrimers.     

Phenylene-containing organosilicon compounds

Summary By condensation of sodium triphenylsilanolate with 1,4-bis(dimethylchlorosilyl)benzene, we synthesized for the first time 1,4-bis[dimethyl(triphenylsiloxy)silyl]benzene, which is a crystalline substance with m.p, 237–238°, distilling at 465–475° without decomposition.     

Nitrogen-containing organosilicon compounds

By the reaction of trialkylsilanes and dialkoxy- or di(chloroalkyl)alkylsilanes with morpholine, thiamorpholine, N-methylpiperazine, and hexamethyleneimine, 14 new organosilicon derivatives of these heterocycles have been synthesized. The addition of perhydroazepine to diethylmethylvinylsilane has been performed.For part XIII, see [1].     

Planar organosilicon polymers

Work on two sheet organosilicon polymers, one derived from the mineral chrysotile and the other from the mineral apophyllite, is described. This work provides direct evidence that both these polymers are composed of sheets. In addition, it shows that in the chrysotile-derived polymer the sheets curl into scrolls, and that in the apophyllite-derived polymer the sheets are essentially flat.     

Furan organosilicon compounds

A series of 2-furyl- and 5-methyl-2-furylorganylhydrosilanes are synthesized by reacting 2-furyllithium and 5-methyl-2-furyllithium with organylchlorohydrosilanes. Furylorganylhydrosilanes reduce HgCl₂ in pyridine to free mercury; while in the presence of H₂PtCl₆ water converts them to the corresponding silanols, with alcohols they undergo dehydrocondensation, and with unsaturated compounds there is hydrosilanation.For Part XI see [1].     

Novel organosilicon betaines

The structure of organosilicon betaines R₃P⁺CMe₂SiMe₂S^– (R = Ph and Me₂N) was determined by X-ray diffraction analysis.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 339–340, February, 1994.     

Nitrogen-containing organosilicon compounds

Fifteen previously unknown piperidinosilanes of the type R_4–m Si[(CH₂) _n NC₅H₁₀] _m (m=1–3; n=0–3). have been synthesized by the reaction of piperidine with diethylaminotrimethylsilane, bis(diethylamino)dimethylsilane, chlorobis(dimethylamino)methylsilane, trichloro(methyl)silane, trialkyl(chloromethyl)silanes, dialkoxy(alkyl)(chloromethyl)silanes, trialkylvinylsilanes, trialkyl(3-chloropropyl)silanes, and 3-chloropropyl(diethoxy)methylsilane. The piperidinosilanes (n>0) have been converted into the corresponding hydrochlorides and methiodides.For part VIII, see [1].