Heteroatom containing polycyclic aromatic hydrocarbons with positive charge - synthesis and characterization

The synthesis and characterization of various heteroatom containing PAHs with positive charge were investigated in this work: 1. A series of 2-phenyl-benzo[8,9]quinolizino[4,5,6,7-fed]phenanthridinylium (PQP) salts with different alkyl chains and anions were synthesized. The synthesis of the extended derivates of PQP salts with two fused benzene rings, 2-phenyl-naphthacene[1,2]quinolizino[3,4,5,6-def]benzo[i]phenanthridinium (DBPQP) tetrafluoroborate was also developed. The self-assembly behavior of these amphiphilic PAHs was investigated in methanolic solution as well as in the bulk. Various aggregates with different morphologies such as fibers, tubes and vesicals were obtained from their solution. All of these morphology changes could be ascribed to the changes in intermolecular interactions which resulting from the difference in the molecular structures such as aromatic cores, alkyl chains and counterions. 2. The synthetic strategy of oxygen containing positively charged PAHs, benzo[5,6]naphthaceno[1,12,11,10-jklmna]xanthylium (BNAX) salts and its dibenzo derivates, DBNAX salts were developed. With a similar method, sulfur containing benzo[5,6]naphthaceno[1,12,11,10-jklmna]thioxanthylium (BNATX) salts were also synthesized. Various BNAX salts with different alkyl chains could be obtained and their supramolecular behavior were investigated. A discotic liquid crystalline behavior was observed for di- (3-25) and tridodecyl (3-27) substituted BNAX salts and both compounds exhibited large unit cell in their 2D-WAXS patterns which could be attributed to the formation of dimer structures. By drop casting their methanolic solution on silicon wafers, similar nanoscaled fibers from monododecyl substituted BNAX bromide 3-24 and DBNAX bromide 3-35 could be observed. 3. A novel synthetic method toward nitrogen containing 14-phenyl-dibenzo[jk,mn]naphtho[2,1,8-fgh]thebenidinium (DBNT) salts was also developed. In this method, the undehydrogenated precursor of DBNT, dibenzoacridinium salt could be produced directly from the reaction between dibenzoxanthenylium derivates and amine/aniline in reasonable yields. Various DBNT salts with different alkyl and alkylphenyl chains on their nitrogen atom were synthesized in this two-step method. The self-assembly behavior of two alkylated DBNT salts, 4-15a and 4-18b was also studied in this work. Compound 4-15a formed nanoscaled fibers and helical aggregates were obtained from 4-18b in their methanolic solutions. 4. Various ionic complexes were derived by complexing PQP and DBPQP cations with different sulfate/sulfonate group containing anionic surfactants. The ionic complexes resulting from the ionic self-assembly (ISA) method exhibited self-assembly behavior which was controllable by the species and shape of cations and anions. Various aggregates such as nanofibers and spherical aggregates could be produced from their methanolic solution in a defined manner conveniently.