Synthesis And Properties Of Boron-nitrogen Doped Acenaphthylenes And BN-cyclopenta[?]phenalenes

Acenaphthylene is a representative member of Cyclopenta-Fused Polyaromatic Hydrocarbons(CP-PAHs),and it is also the smallest subunit of Fullerene.Modification aceanphthylene or aceanphthylene-like PAHs is a fundamental problem to be solved.On the other hand,replacement of CC units with an isoelectronic BN units is an effective strategy to regulate the properties of PAHs.In this thesis,we took BN-aceanphthylene and BN-aceanphthylene-like PAHs as the target molecules,exploring their synthetic methods,reactivity,optoelectronic properties and potential application in the field of optoelectronic materials.In the first part,we developed a simple synthetic route to synthesize BNacenaphthylenes and its derivatives,and obtained compounds 4a-4g successfully,and one of them was unambiguously confirmed by X-ray single crystals.We have also carried out photophysical studies,electrochemical studies and DFT theoretical calculation on the synthesized BN-acenaphthylenes.The experimental results and theoretical calculation results indicated that BN-doping can adjust the electronic structure of the molecule effectively,resulting unique optoelectronic properties of the BN-acenaphthylenes.The calculated NICS(1)value,combined with the nuclear magnetic resonance and single crystal structure analysis,showed that the weak aromaticity character of the boronnitrogen sub-rings within the BN-acenaphthylenes.In addition,we systematically studied the reactivities of BN-acenaphthylenes,including oxidation,reduction,electrophilic substitution reaction and so on,and a series of functionalized BN-acenaphthylenes 5a-5c and 6a-6f were obtained.In the second part,a series of BN-cyclopenta[?]phenalene compounds 7a-7f were synthesized by Suzuki coupling,oxidative coupling and electrophilic borylation reaction.The calculated NICS(1)value,combined with the nuclear magnetic resonance and single crystal structure analysis,showed that the weak antiaromaticity character of the boronnitrogen sub-rings within the BN--cyclopenta[?]phenalenes 7a-7f.7a-7f exhibited high fluorescence quantum yield and long fluorescence lifetime,and the absolute fluorescence quantum yield is up to 0.93.In addition,we also investigated the response of 7a-7f towards fluoride ions.The absorption and emission peaks of these compounds showed blue shift upon adding fluoride ions.This results demonstrated that 7a-7f might be used as fluoride ion sensors in the future.Overall,the thesis is focusing on the design and synthesis of novel BN—acenaphthylenes and BN-cyclopenta[?]phenalenes.We investigated the photophysical properties of the synthesized BN-PAHs.Hopefully,the results can pave a way for the further design and application of these BN-PAHs.