UV,IR, and PMR spectra and structure of 2-thiaindan and 2,3-dithia-1,2,3,4-tetrahydronaphthalene

The UV, IR, and PMR spectra of 2-thiaindan (I) and 2,3-dithia-1,2,3,4-tetrahydronaphthalene (II) have been studied. In contrast to the spectra of dibenzyl sulfide (III) and dibenzyl disulfide (IV), the UV spectra of I and II show no gem conjugation between the unshared electrons of the sulfur atom and the aromatic ring. Also in favor of this are the PMR spectra of I and II, in which the values of CH₂ are lower than in III and IV. The low activation energy of the transformation of one conformation of the heterocycle into the other, particularly in the molecule of I, shows its almost planar structure, which is an obstacle to gem conjugation.Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 6, No. 7, pp. 885–890, July, 1970.     

Atranes. V. Proton magnetic resonance spectra of organyl and organoxysilatranes

The proton magnetic resonance spectra of eight organyl- and organoxysilatranes, (R = CH₃, C₂H₅, i-C₃H₇, CH₂=CH, C₆H₅, CH₃O, C₂H₅O, n-C₃H₇O) are investigated. The PMR resonance signals are interpreted, taking into account magnetic anisotropy of substituents and d-p interaction effects. The present communication gives results of proton magnetic resonance (PMR) studies of organyl- and organoxysilatranes (I). The table shows the compounds studied and the chemical shifts of the magneto-equivalent groups of protons in their spectra (see figure).For part IV see [1].     

Crystal and molecular structure of the (N-Si) chelate of 2-(chlorodimethylsilylmethylthio)-1-pyrroline

The X-ray diffraction structural study of the (N-Si)-chelate of 2-(chlorodimethyl-silylmethylthio)-1-pyrroline was carried out (R = 0.033 for 1894 reflections). The Si atom has a somewhat distorted trigonal bipyramidal coordination with the Cl and N atoms in axial positions. The Si-Cl and Si-N distances (2.423(1) and 1.945(1) Å) belong, respectively, to the longest and shortest known Si-Cl and Si-N distances in pentacoordinated silicon derivatives with an axial N-Si-Cl moiety.Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 189–192, January, 1993.     

Si-Containing Amides of Phosphoric Acid

The first representative of the N-silylmethylamides of phosphoric acid O=P[NMe(CH₂SiMe _n (OEt)_3-n ]₃ have been synthesized by interaction of MeNHCH₂SiMe _n (OEt)_3-n (n = 2, 3) with POCl₃. The interaction of the N,N′,N″-trimethyl-N,N′,N″-tris[(ethoxydimethyl- silyl)methyl]triamide phosphoric acid with BF₃·Et₂O or BCl₃ results in the formation of the N,N′,N″-trimethyl-N,N′,N″-tris[(fluorodimethyl-silyl)methyl]triamide phosphoric acid or N,N′,N″-trimethyl-N,N′,N″-tris[(chlorodimethylsilyl)methyl]triamide phosphoric acid. NMR data show on the tetracoordinate state of silicon in these products.     

α-Ketothioketene dimers

Conclusions When,-dichlorovinyl ketones are reacted with Na₂S, NaSC(S)N(C₂H₅)₂, KSC(S)OC₂H₅, and NaSCOCH₃, two types of sulfur-containing heterocyclic compounds are formed: 1,3-dithietanes and 1,3-dithiols , at which time the ratio of the products depends on the nature of the sulfur-containing nucleophilic reagent.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2940–2048, September, 1976.     

1-Fluoro-2-hydrostibatrane

1-Fluoro-2-hydrostibatrane was synthesized by the reaction of antimony trifluoride with triethanolamine. The molecular structure of the compound was studied by X-ray diffraction and multinuclear magnetic resonance. The coordination polyhedron of the Sb atom is intermediate between a distorted tetrahedron (AX₄E type of molecule) and a tetrahedral pyramid (AX₄DE type of molecule). Diastereotopism of the geminal protons of each methylene group in the half-rings of the heterocycle, observed in the NMR spectra, vanishes at 65°C because of reversible cleavage of the N → Sb coordination bond and inversion of the nitrogen atom. The chemical environment of the OCH₂ and NCH₂ protons of the heterocycle and 2-hydroxyethyl protons is averaged due to the fast prototropic tautomerism at 75–120°C (in DMSO-d ₆).     

Reaction of diphenyl[2-(triethoxysilyl)ethyl]phosphine oxide with boron trifluoride etherate

Diphenyl[2-(trifluorosilyl)ethyl]phosphine oxide was synthesized by the reaction of diphenyl[2-(triethoxysilyl)ethyl]phosphine oxide with boron trifluoride etherate. As shown by the ¹H, ¹³C, ¹⁹F, ³¹P, ²⁹Si multinuclear NMR spectroscopy data, the silicon atom in the molecule is tetracoordinate. The absence of P=O→Si interaction in diphenyl[2-(trifluorosilyl)ethyl]phosphine oxide, as follows from the comparison of the calculated [GIAO B3LYP/6-311++G(2d,p)] and experimental δ(²⁹Si) and δ(³¹P) values, is due to the formation of complex with BF₃ by the phosphoryl oxygen.     

Reaction of trialkyl-(3-aminopropyl)silanes with formaldehyde and elemental sulfur

Conclusions N-(3-Trialkylsilylpropyl)formamides (II) and N,N-bis(3-trialkylsilylpropyl)thioureas (III), together with a small amount of the trialkyl-(3-isothiocyanatopropyl)silane, are formed when trialkyl-(3-aminopropyl)silanes are reacted with formaldehyde and sulfur in aqueous-ethanol medium. 1,3,5-Tris(trialkylsilylpropyl)hexahydrotriazines are the intermediate products in these reactions.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 666–668, March, 1977.     

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].