Yu. P. Kudryavtsev

An interaction of amorphous carbyne with sodium: the formation of carbyne intercalation compounds

Abstract The carbyne intercalation compound with sodium (CICue5f8Na) has been synthesized for the first time using the chemical-transport reaction of amorphous carbyne with sodium metal in vacuum. A structural model of the intercalation compound has been proposed on the basis of experimental electron diffraction data. The molecular structure of carbyne chains in the intercalation compound has been confirmed by chemical properties. The interaction of CICue5f8Na with nitric acid does not result in the complete removal of alkali metal, residual sodium atoms orient carbyne chains during the crosslinking process. The carbyne single crystals thus formed can be considered as residue intercalation compound.

Synthesis and properties of valuable polymers of carbon

1. n nA new polymer of carbon was produced by the reaction of oxidative polydehydrocondensation of acetylene. n n n n n2. n nOur investigations of the structure of the polymer (formation of oxalic acid and carbon dioxide after treatment with ozone, data of IR spectroscopy and x-ray diffraction study, as well as the data of highvoltage electronic microscopy and microdiffraction, countersynthesis of fragments of the polymer from polyvinylidine chloride, and determination of the low-temperature heat capacity and heat of combustion) permit us to conclude that together with the known allotropic modifications of carbon — diamond and graphite, there is a third allotropie modifcation — carbyne, which is realized in the form of two new crystalline forms of carbon — the polyyne and cumulene forms.

The Discovery of Carbyne

The history of the discovery of carbyne is briefly recalled. The existence of carbyne was first disclosed by Russian researchers in 1960. It was obtained for the first time via oxidative dehydropolycondensation of acetylene based on the Glaser coupling of ethynyl compounds.

Structural transformations of the cumulene form of amorphous carbyne at high pressure

Structural transformations of the cumulene form of amorphous carbyne which are induced by heating at high pressure (7.7 GPa) are investigated. These can be described by the sequence amorphous phase — crystal — amorphous phase — disordered graphite. Raman scattering shows that predominately the chain structure of carbyne remains at the first three stages. It was found that the intermediate crystalline phase is an unknown modification of carbon whose structure is identified as cubic (a=3.145 Å). A mechanism of structural transformations in carbyne that involves the formation of new covalent bonds between chains is discussed.

AN EFFICIENT DEHYDROFLUORINATING SYSTEM FOR POLYVINYLIDENE FLUORIDE

Chemical dehydrohalogenation of halogen-containing polymers is an accessible and convenient method for preparation of carbon-chain polymers with a system of conjugated multiple bonds in the main chain, including carbyne [1]. The development of an efficient method of preparation of carbyne and articles made of it is still an urgent problem. It was previously shown that chemical dehydrohalogenation of polyvinylidene halides (PVDH) with an alcohol solution of a base causes the formation of a cumulene modification of carbyne [2]:

Dehydroplycondensation of acetylene

Syntheses of carbyne via oxidative dehydropolycondensation of acetylene and butadiyne will be described and the role of terminal copper atoms in the stabilization of lower polyynes will be discussed.

Chemical reactions of dialkoxytitanium oxides

1. n nThe first members of a previously unknown class of titanium-containing organic compounds were prepared; chloroethoxy-, chloropropoxy-, and butoxychloro-titanium oxides. n n n n n2. n nBy the action of chlorine on diproproxy- and diisobutoxy-titanium oxides, compounds of the following compositions were obtained: Cl2TiO · 2n-C3H7OH and Cl2TiO · 2i-C4H9OH. n n n n n3. n nBy the reaction of dialkyldichlorosilanes with dialkoxytitanium oxides, doubly bound oxygen is replaced by two chlorine atoms: n n

Plasmochemical synthesis of carbene

left( {n - C_3 H_7 O} right)_2 TIO + Cl_2 SiR_2 to left( {n - C_3 H_7 O} right)_2 TiCl + left[ {OSiR_2 } right]_x