Organic crystals, crystal structure irradiated

Tetraethylammoniumhis(tetracarbonyliron)bis(/i-tetracarbonyliron)dithal-late(2 — ), [Et4N]2[Tl2Fe4(CO)16], decomposes rapidly upon exposure to air and is soluble in MeOH, CH2C12, and most polar organic solvents. Its crystal structure shows it to be a weak dimer of [Tl Fe(CO)4 2] and it probably exists as the monomer in solution.15 IR (CH2C12, cm-1) 1985(m), and 1908(s). It may be oxidized or irradiated to yield higher nuclearity thallium-iron carbonyl compounds.14,15... 

This article describes the solid state polymerization of 1,i-disubstituted butadiene derivatives in perovskite-type layer structures, in layered structures of organic ammonium halide salts, and in lipid layer structures. Recent investigations by spectroscopic methods and x-ray structure analyses are described. The studies clearly indicate that the photolysis in the crystalline state leads to the formation of 1,i-trans-polymers exclusively. Crystal structure analyses of monomeric and polymeric layer perovskites demonstrate that upon y-irradiation a stereoregular polymer is obtained in a lattice controlled polymerization. 

Some Effects of Crystal Structure on Production of Radicals in Irradiated Organic Crystals... 

Molecular Crystals Fullerites. Organic crystals are usually prone to ionization damage and decompose very rapidly under electron irradiation they can thus be studied for only a short time (a few. seconds) and only with a very low electron beam intensity. Transmission electron microscopy has, therefore, seldom been applied to organic crystals. However, the all-carbon molecules Qo, C70. etc., (fullerenes) discovered at the end of the 1980s resist electron radiation fairly well. Early structural studies on the crystalline phases of ftil-lerenes (fullerites) were performed mainly by electron microscopy because only small quantities of sufficiently pure material were available. At room... 

The polymerization proceeds under photo- [49,50],X-ray [51], and y-ray [52] irradiation in the dark in vacuo, in air, or even in water or organic solvent as the dispersant (nonsolvent) for the crystals, similar to the solid-state polymerization of diacetylene compounds [ 12]. The process of topochemical polymerization of 1,3-diene monomers is also independent of the environment surrounding the crystals. Recently, the thermally induced topochemical polymerization of several monomers with a high decomposition and melting point was confirmed [53]. The polymer yield increases as the reaction temperature increases during the thermal polymerization. IR and NMR spectroscopies certified that the polymers obtained from the thermally induced polymerization in the dark have a stereoregular repeating structure identical to those of the photopolymers produced by UV or y-ray irradiation. 

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