Matrix isolation parent structure

Thiazol-2-ylidenes are less well studied than their imidazole and triazol analogues. Only one isolated and structurally characterised example is known in the literature, the 3-(2,6-diis opropylphenyl)thiazol-2-ylidene synthesised by Arduengo et al. in 1997 [2] (see Figure 6.8). The parent compound, 2,3-dihydrothiazol-2-ylidene, was generated in an argon matrix at 10 K from thiazol-2-carboxylic acid as the starting material [33] (see Figure 6.9). 

A derivative of cyclopentyne has been trapped in a matrix. Although cycloheptyne and cyclohexyne have not been isolated at room temperatures, Pt(0) complexes of these compounds have been prepared and are stable." The smallest cyclic allene" so far isolated is l-/err-butyl-l,2-cyclooctadiene 107." The parent 1,2-cyclooctadiene has not been isolated. It has been shown to exist transiently, but rapidly dimerizes." " The presence of the rert-butyl group apparently prevents this. The transient existence of 1,2-cycloheptadiene has also been shown," and both 1,2-cyclooctadiene and 1,2-cycloheptadiene have been isolated in platinum complexes." 1,2-Cyclohexadiene has been trapped at low temperatures, and its structure has been proved by spectral smdies." Cyclic allenes in general are less strained than their acetylenic isomers." The cyclic cumulene 1,2,3-cyclononatriene has also been synthesized and is reasonably stable in solution at room temperature in the absence of air." ... 

The present studies are mainly devoted to silicon carbide (SiC)-based materials in the form of isolated clusters, nanopartides, or several architectures, which exhibit various original features. The interests in SiC is motivated by the large offered possibihties from structural aspects as well as physical responses such as electronic, optics, photovoltaic or dielectric properties. Additionally, beyond good thermal stability and mechanical hardness, the SiC is versatile from structural aspect (more than 170 polytypes), electronic behavior (a variable energy gap from 2.4 to 3.3 eV) as well as photorefractive properties (Vonsovici et al. 2000). As matter of fact, the nanocrystalline size modulates all the intrinsic parameters involved in the parent bulk materials. When nanopartides are associated with suitable matrixes, promising new potentialities... 

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