Selective Cleaving C-C Bond Reaction Of Polyaryl Cyclopentadienes And Luminescent Properties Of The Products

Selective cleaving C-C bond is one of the most important reactions in organic synthesis, and thus becomes hot topics both in the fields of target-oriented organic synthesis and methodology development. In current research, organic photo-electric functional compounds were designed based on selective C-C bond cleavage of cyclopentadiene compounds, and various influence factors including oxidants, catalysts and substituents were considered. Three synthetic routes originated from cyclopentadiene compounds were developed in term with three different luminescent compounds:polyketenes, pyrylium tetraferrichlorate and naphthalene derivates. The products with conjugated structure perform good luminescence property, such as aggregation induced emission (AIE) and electroluminescence emission (EL). The study centered the selective C-C bonds cleavage of cyclopentadiene rings consists of four parts as below:1Synthesis and aggregation induced emission enhancement (AIEE) property of poly-aryl substituted cyclopentadienes. A series of poly-aryl substituted cyclopentadienes were synthesized and carefully characterized. The AIEE property of these materials were investigated and discussed in term with molecular configuration. It is proposed that the C-H-…π intereaction fixed nonplanar molecular structure account for their AIEE performance.2Synthesis of polyketene derivates via Csp2-Csp3bonds cleavage of cyclopentadiene derivates and metal reduction of pyrylium. Metal reduction of a-free pyrylium which were prepared by perchlorates catalyzed Csp2-Csp3bonds cleavage reaction of cyclopentadiene derivates, a series of polyketene compounds were obtained via Claisen rearrangement of dimerization intermediates6,6’-bipyran. However, metal reduction of unfree pyrylium lead to different dimmers determined by substituents. The X-ray single crystal analysis indicates intramolecular interactions (C-H…π, π-π) play the key role on crystallization induced emission (CIE) property of the products. This result was demonstrated by their variational UV absorption spectra.3Addition of H+on Csp2-Csp2bonds of p-methoxyphenyl substituted cyclopentadiene compounds led to cyclopentaenyl carbeniums togethering with their solvent-induced-degeneration reactions. A series of room-temperature stable cyclopentaenyl carbenium were produced by H+addition Csp2-Csp2bonds of cyclopentadiene rings. The p-methoxyphenyl substituent was supposed to guide the reaction and stabilized the carbocations. The planar five-member ring determined by X-ray single crystal analysis defined them as the carbeniums. These carbeniums degenerated in diverse approaches while dissolving in different polarity solvents. It is notable that in acetonitrile they converted to naphthalene derivates. which have delivered superb blue EL emission.4Hexahydrated ferric chloride catalyzed Csp2-Csp2bonds cleavage of poly-aryl substituted cyclopentadienes to synthesize pyrylium tetrachloroferrates. By oxygen insertion of Csp2-Csp2bonds, the cyclopentadiene rings expanded to pyrylium salts. Hexahydrated ferric chloride plays multiple roles in reaction, including catalyst, oxidant and reactant. Owing to the counter anion of tetrachloroferrate, the fluorescent pyrylium salts are water-soluble and stability-enhanced, which can endure alkali erosion. The cell-staining experiments of the pyrylium salts were successfully preceded on Hela cell.