|
Xylylene comprises two isomeric organic compounds with the formula C6H4(CH2)2. These compounds are related to the corresponding quinones by replacement of the oxygen atoms by CH2 groups. ''ortho''- and ''para''-xylylene are best known, although neither is stable in solid or liquid form. Certain substituted derivatives of xylylenes are however highly stable, an example being tetracyanoquinodimethane. ==Synthesis and reactivity== ''p''-Xylylene forms upon pyrolysis of ''p''-xylene or, more readily, the α-substituted derivatives (see equation). Upon condensation, ''p''-xylylene dimerizes with moderate efficiency to give ''p''-cyclophane:〔H. E. Winberg, F. S. Fawcett "()Paracyclophane" Organic Syntheses, Coll. Vol. 5, p.883 (1973); Vol. 42, p.83 (1962) (Link ).〕 Further heating of the ''p''-cyclophane gives poly(''para''-xylylene). The reaction of α,α'-dibromo-''o''-xylene with iron carbonyls affords low yields of the xylylene complex Fe(CO)3(). This complex is similar to Fe(CO)3().〔R. C. Kerber, E. C. Ribakove "Formation of iron carbonyl complexes of reactive polyenes from dihalides involving the free polyene" Organometallics, 1991, volume 10, pp 2848–2853.〕 At high temperatures, benzocyclobutenes can undergo electrocyclic ring-opening to form ''o''-xylylenes. This and other syntheses of ''o''-xylylenes, and their subsequent dimerization by () cycloaddition to form cycloctyl structures, were used repeatedly in the synthesis of superphane. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「xylylene」の詳細全文を読む スポンサード リンク
|