Formation and Reactivity of 2-Styryl-1,4-benzoquinones
摘要:
The 2-styryl-1,4-benzoquinones 7a,b, generated by the oxidation of the corresponding hydroquinones 6a,b, dimerize at room temperature in a Diels-Alder reaction. The strictly chemo, regio- and stereoselective process can be rationalized by means of frontier orbital interactions, The polycyclic adducts 8a,b undergo a further intramolecular cycloaddition (8a,b --> 10a,b) after oxidation on silica gel.
Synthesis and photo-physical properties of methoxy-substituted π-conjugated-2,2′-bipyridines
摘要:
4,4'-Bis-vinly-2,2' bipyridines have been known in the area of materials chemistry since last few decades. Bipyridine molecules bearing donor substituents in their pi backbone are examples of 'push-pull' molecules. Emissive properties of such ligands depend on the position of the donor unit in their pi backbone. The Horner-Wordsworth-Emmons reaction has been used extensively to synthesize such types of conjugated systems. Three newly synthesized highly conjugated 2,2' bipyridines (3a-c) have been described. The molecules 3a-c are highly emissive in the visible region at room temperature. (C) 2010 Elsevier Ltd. All rights reserved.