Abstract
Chapter I： We reported regiocontrolled syntheses of ethene-bridged para-phenylene oligomers in three distinct classes using Pt(II)- and Ru(II)-catalyzed aromatization. This synthetic approach is developed based on two-fold aromatization of 1-aryl-2-alkynylbenzene functionality, which proceeds via distinct regioselectivity for platinum and ruthenium catalysts. Variable-temperature NMR spectra provide evidence that large arrays of these oligomers are prone to twist from planarity. The ultra violet (UV), photoluminescence (PL) and band gaps of these regularly growing arrays show a pattern of extensive π-conjugation with increasing array sizes except for one instance. Chapter II： Part 1：A facile synthesis of three series cata-condensed polyaromatic hydrocarbons, initial ICl-promoted cyclization of bis(biaryl)acetylenes, followed by the Mizoroki-Heck coupling reaction has been reported. This approach works well for various bis(biaryl)acetylenes to afford dibenzo[g,p]chrysenes as core structure and extended the conjugated benzene ring from different direction. The photophysical and electronic properties of these highly twist cata-ondensed polyaromatic hydrocarbons has affected by aromaticity and the position of new extended conjugated benzene ring. Part 2：We also demonstrated Pt(II)- and Ru(II)-catalyzed cyclization of 1,3,5-(tri-4-tert-butylbenzene)-2,4,6-triethynylbenzene to synthesis new cata-ondensed polyaromatic hydrocarbons. Chapter III： Part 1：A new synthesis of large PAHs with low Clar sextets was developed. Dibenzochrysene derivatives can be transformed into planar polyaromatic hydrocarbons by using DDQ-oxidation reaction. The photophysical and electronic properties of these compound including UV/Vis, photoluminscence and cyclic voltammetry indicate that these properties are greatly affected by the increasing array size. Part 2：We have developed a new synthesis of large-sized PAHs with low Clar sextets. This two-step synthesis involves starting bis(biaryl)diynes, which undergo initial PtCl2-catalyzed aromatizations, and subsequent DDQ-oxidation. The resulting PAH products have aromatic characters on the outer benzenes and polyene properties on indicates an efficient electron-delocalization within the frameworks of these PAHs. This convenient approach is applicable to a large PAH that has small energy gap (2.07 eV). Chapter IV： The last chapter study for interior aromatic addition chemistry on planar dibenzo[de, op]bisanthracene (DBBA), unfortunately we didn’t find any evidence for addition chemistry on interior carbon, but still find some interesting reaction bear high regioselectivity on DBBA compound, such as Friedal-craft reaction, nucleophilic addition, epoxidation and new type intermolecular Scholl reaction.