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.     

New polyunsaturated organosilicon dendrimers

Spherical dendrimer of regular structure with the spatial characteristic S = 5, tetrakis[tris-(trimethylsilylethynyl)silyl-2-vinyldimethylsilylethynyl]silane, and the unsymmetrical binuclear dendrimer containing simultaneously groups (−CH₂CH₂−), (−CH=CH−), (−C≡C−) and combining the branches of the zero order (G0) and of the second generation (G2), 2-tris(trimethyl-silylethynyl)silyl-1-tris[tris(trimethylsilylethynyl)silylvinyldimethylsilylethynyl]silylethane were isolated from the reaction of hydrosilylation of tetrakis (dimethylethynylsilylethynyl)silane and vinyltris(dimethylethynylsilylethynyl)silane with trichlorosilane and a subsequent treatment of the reaction products with trimethylsilylethynylmagnesium bromide. NMR spectra of the synthesized compounds were studied.     

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.     

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.     

Comparative study of the biological activity of organosilicon and organogermanium compounds

The literature data and the results of our own investigations on the comparative study of the biological activity of isostructural organogermanium and organosilicon compounds have been summarized. It has been shown that the series of organogermanium and organosilicon compounds is more active than the carbon analogues, the majority of organogermanium compounds are less toxic than the sila analogues, the biological activity of the compounds under study appears to be similar but can dramatically differ in the degree of activity, and, moreover, in some particular cases sila and germa analogues exhibit the opposite biological effects.     

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.     

Synthesis of new organosilicon and organogermanium derivatives of diallylisocyanurate and cyanuric acid

Conclusion The reactions of the silver, cesium or rubidium salts of diallylisocyanurate and of trimethylsilyldiallylisocyanurate with pentamethylchlorodisilane, 1,2-dichlorotetramethyldisilane, 1,3-dichlorotetramethyldisiloxane and -(trialkylgermyl)propionyl chlorides leads to the corresponding organosilicon and organogermanium triazine derivatives. The reaction of pentamethylchlorodisilane with the trisilver salt of cyanuric acid or tris(trimethyl-silyl) cyanurate leads to the formation of tris(pentamethyldisilanyl)cyanurate.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 941–943, April, 1987.     

Synthesis of organosilicon and organogermanium polymers containing tetraacetylenic groupings in the chain

Conclusions The thermal dehydropolycondensation of bis(diacetylenyl)diphenylsilane and bis(diacetylenyl)diphenylgermane gave polymers containing tetraaeetylene groupings in the chain between the Si and Ge atoms, whose electrophysical and catalytic properties were studied.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2121–2122, September, 1972.     

Medium-sized organometallic derivatives : IX. transannular nucleophilic substitution in organosilicon and organogermanium eleven-membered rings

Olah's reagent (HF-pyridine) reacts easily at room temperature with 6,6-dimethyl-6-sila-(and 6,6-dimethyl-6-germa-)-cycloundecanols. In each case, the principal product formed is not the expected cyclic organosilicon (or organogermanium) fluoride but the compound resulting from a transannular substitution reaction at the heteroatom with cleavage of one intracyclic heteroatom-carbon bond. The structures of the derivatives obtained were determined by ¹⁹F NMR and, after methylation, by mass spectrometry, ¹H and ¹³C NMR, and chemically.     

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     

The first ionization potentials and conjugation in benzene derivatives containing organosilicon, organogermanium, organotin, and organolead substituents

The inductive and resonance effects of silicon-, germanium-, tin-, and lead-containing and some organic substituents on the HOMO energies (E _HOMO) for 43 monosubstituted andp-disubstituted benzene derivatives were analyzed in the Koopmans approximation. A linear dependence between the perturbation energy δE and the resonanceσ _R ⁺ parameters of the substituents was established. The Koopmans approximation is a rough approximation for the compounds studied, since to provide for its rigorous fulfilment, the δE values must depend on the σ _R ⁰ parameters of the substituents. The principal regularities of increasing the σ,π-conjugation between the organoelement substituents and the π-system caused by a positive charge on the benzene ring were established. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 70–75, January 1997.     

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.     

有机锗倍半硫化物的合成及性质研究

为了系统地研究有机锗倍半硫化物的抗癌活性, 寻找更有效的抗癌药物, 合成了15个有机锗倍半硫化物(GeCH2CHRCONHAr)2S3, 并以此类化合物为模型化合物研究了有机锗倍半硫化物的化学性质. 用IR, HNMR证实了它们的组成和结构, 还研究了它们的水解反应以及与盐酸, 氢溴酸的反应.     

Application of electronic and ir spectroscopy to the determination of σp-, σ+p- and σoR-constants of some organosilicon and organogermanium substituents

The σ_p- and σ⁺_p- constants of some silicon- and germanium-containing substituents have been determined from electronic absorption spectroscopy data of charge-transfer (CT) complexes of phenylgermanes, benzylsilanes and benzylgermanes with tetracyanoethylene (TCNE). Resonance constants of corresponding substituents have been determined from the integrated intensity values of aromatic ring stretching modes (IR spectroscope data) of benzylsilanes and benzylgermanes. It is shown that the effect of dπpπ interaction in phenylgermanes remains practically unchanged in the course of the transition from the ground state to the CT state. The high negative values of σ⁺_p-constants for benzylorganosilicon and benzylorganogermanium substituents indicate the presence of considerable σ, π-conjugation in the CT state of benzylsilanes and benzylgermanes. This effect is also established for the ground state of the above mentioned compounds from their σ^o_R-values. The effect of σ,π-conjugation is displayed in greater degree in the ground state as well as in the CT state in benzylgermanes as compared with benzylsilanes.