دانلود کتاب ترکیب، خواص و کاربردهای هلیسنس

Helicenes are the archetypal helical molecules simply composed of ortho-condensed aromatic rings whose helical shape derives from the steric repulsion of terminal cycles or substituents. It leads to configurationally stable helices with minus (M) or plus (P) handedness. These chiral polycyclic hydrocarbons have attracted the attention of chemists for decades, not only because of their beautiful 3D helical topology artificially mimicking natural helical structures such as double-stranded DNA or snail shells but also because of their many appealing physicochemical properties and consequent applications in various fields of research. Over time, the structural diversity of helicenes has grown considerably and many synthetic approaches have been developed to access a variety of helical scaffolds decorated with a decent range of heteroatoms, functional groups, ormetal ions. With advances in chiral high-performance liquid chromatography (HPLC) methodologies, nonracemic helicenes have become accessible via racemate resolution. Alternatively, new stereoselective synthetic procedures have been developed to receive helicenes in a nonracemic form.