Vinylidene solid state structure

The number of known, isolated and characterized complexes depends strongly on the length of the chain and drastically decreases with the number of carbon atoms in the chain. A great number of vinylidene complexes of many metals, with different terminal substituents R and various co-ligands have been synthesized and the reactivity has been studied extensively. At present, the solid-state structure of more than 230 vinylidene complexes has been determined by X-ray structure analyses. The number of isolated allenylidene complexes is somewhat smaller. 

Evsyukov, S.E. Paasch, S. Thomas, B. Heimann, R.B. Fonnation of carbynoid structures by chemical dehydrochlorination of poly(vinylidene chloride). A C solid-state NMR study. Ber. Bunsen-Ges. Phys. Chem. 1997, 101(5), 837-841. 

Based on the experimental data on vinylidene chloride pofynerization in the presence of linear dextrin, a chemical interaction between poly(vinylidene chloride) and p-cyclodextrin was ruled out The results of the experiments demonstrated an absence of a chain transfer to linear dextrin, i.e. an absence of chemical bonds. In addition, comparing the data of investigation of the structure of obtained compounds indicated a nonchemical bonding of p-cyclodextrin and poly(vinylidene chloride). Due to the identity of the crystalline structure of monomeric adducts of P-cyclodextrin with both MMA and vinylidene chloride, on the one hand, and to the formation of an unstable product by a solid-state polyn rization of p-cyclodextrin with MMA (dissociates into P-cyclodextrin and PMMA on being treated with hot water), on the other hand, these researchers also assumed an absence of chemical bonds in the stable product, obtained in the same way and consisting of poly(vinylidene chloride) and p-cyclodextrin. 

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