Nucleophilic Degradation Research Articles

ChemInform Abstract: Formation of the (7‐SeB10H11)‐ Anion from 1‐SeB11H11 and the Structure of the Anion Studied by 11B COSY NMR and X‐Ray Crystallography.

AbstractThe title ion has been prepared by nucleophilic degradation of 1‐SeB11H11 (I) using NaOEt in refluxing EtOH solution followed by precipitation of the anion with aqueous (Et4N)I solution.

The formation of the [7-SeB10H11]− anion from 1-SeB11H11 and the structure of the anion studied by boron-11 cOSY NMR and x-ray crystallography

Abstract The [7-SeB10H11]− anion has been prepared by the degradation of 1-SeB11H11 with NaOEt in ethanol. Data from 1H, 11B and 11B−11B COSY NMR spectra have enabled the structure of the anion in solution to be assigned. An X-ray diffraction study of [Et4N][7-SeB10H11] showed the crystals to be monoclinic, space group P21/c with two formula units in each unit cell of dimensions a = 8.485(2), b = 10,654(2), c = 10.078(2) A,β = 91.10(2)°. 1985 unique reflections were measured, but only the 547 with I ⪢ 3σ(I) were labelled “observed” and used in the structure solution and refinement. Both cation and anion lie on independent inversion centres and are disordered. In the anion, the Se atom was scrambled unequally over 12 sites. The final R value is 0.12. An analysis of the MNDO calculated composition of the five lowest energy unoccupied m.o's. of the sulphur analogue of SeB11H11 was carried out. The results suggest that the B-atom lost in the nucleophilic degradation reaction will be from a position adjacent to S(Se). This is supported by experimental data.

Transformations of the m‐carborane cage in m‐carborane‐containing polyamides having different structural units in the chain

Abstractm‐Carborane‐containing polyamides having different structural units in the chain are formed by nucleophilic degradation of the carborane cage of m‐carborane‐containing polyamides. The structure of dicarbaundecaborate‐containing polymers was investigated by IR and NMR spectroscopy. Some chemical and physico‐chemical properties of these polymers were studied. It was shown that dicarbaundecaborate‐containing polyamides when kept in air decompose with complete degradation of the polyhedral structure of carborane.

Salts of sulfane-α,ω-bis(fluorodithiophosphoric acids)

In aqueous medium P 4S 10 reacts with sodium fluoride yielding sodium difluoropentathiodiphosphate, Na 2[P 2S 5F 2][1]. It was found that in acetonitrile sulfur-rich phosphorus sulfides (the S:P ratio varying from 11:4 to 16:4) react with fluoride under formation of alkali sulfane-α,ω-bis(fluorodithiophosphates) of the general formula 1 ▪ The higher the sulfur content of the sulfur-rich phosphorus sulfides the higher are the yields of sulfane derivatives. These sulfane-α,ω-bis(fluorodithiophosphates) are identified by 19 F and 31 P NMR spectroscopy. For the trisulfane derivative 2 ▪ long range couplings over six bonds are observed. These results may be explained by the assumption of a substitution of S-atoms in the P-S-P bridges of the adamantane-like P 4S 10 molecule by S n-units in the sulfur-rich phosphorus sulfides. On the other side solutions of alkali pentathiodifluorodiphosphates in CH 3CN react with sulfur also to a mixture of compounds of type 2 . Therefore the nucleophilic degradation of P 4S 10+m(m=1−5) with fluorides do not allow definite conclusions about the molecular structure of the starting compounds.

Synthesis and investigation of the properties of polymers containing dicarbaundecaborate

AbstractPolymides containing dicarbundecaborate moieties (1) are formed by nucleophilic degradation of polyamides containing 1,7‐dicarba‐closo‐dodecaborane(12) (m‐carborane) moieties in the polymeric chain. The formation of polyamides 1 is accompained by decomposition of the polymeric chain. Potassium cations in the dicarbundecaborate moieties were shown to be easily replaced by protons. The structure of polymers containing exclusively dicarbaundecaborate units (2) was investigated by IR and 1H NMR spectroscopy. Some chemical and physico‐chemical properties of these polyamides were studied.

Central role of the trisulfur trinitride(1-) and tetrasulfur pentanitride(1-) ions in the deprotonation of tetrasulfur tetraimide and in the reductive or nucleophilic degradation of tetrasulfur tetranitride

Central role of the trisulfur trinitride(1-) and tetrasulfur pentanitride(1-) ions in the deprotonation of tetrasulfur tetraimide and in the reductive or nucleophilic degradation of tetrasulfur tetranitride

Synthese und einige reaktionen von lithium-triphenylzinn-sulfid

Triphenylstannyllithium is synthesized by the reaction of lithium with triphenyltin chloride in tetrahydrofuran. It reacts with elemental sulphur in a stepwise nucleophilic degradation reaction, forming lithium triphenyltin sulphide. This compound undergoes metathetic reactions with benzoyl chloride, triphenyltin chloride, triphenylgermanium bromide and triphenyllead chloride, whereby triphenyltin thiobenzoate, bis(triphenyltin)sulphide, triphenyltin triphenylgermanium sulphide and triphenyltin triphenyllead sulphide are formed.

192. Conformational and electronic factors influencing the nucleophilic degradation of diethylsulphonylglycopyranosylmethane derivatives

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191. The nucleophilic degradation of diethylsulphonylglycopyranosylmethane derivatives

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