Effect Of Alkyl Chain Length And Linking Position On Optical Properties Of9,10-divinylanthracene

In this paper, we have synthesized two series of9,10-divinylanthracenederivatives by adjusting the length of the alkyl chains and changing the linkingposition of alkoxystyryl:9,10-bis(p-alkoxystyryl)anthracenes(DSA-OCn) and the9,10-bis(alkoxystyryl)anthracenes (OCn) with different linking position ofalkoxystyryl. We have systematically studied the properties of two series of9,10-divinylanthracene derivatives by fluorospectro photometer, ultravioletspectrophotometer, XRD, DSC, infrared spectroscopy and single crystal X-raydiffractometer.1We have systematically demonstrated the chain length-dependent PFCbehaviour of9,10-bis(p-alkoxystyryl)anthracenes (DSA-OCn) through the pressing,annealing, repressing and solvent-fuming cycle. It is shown that long alkyl-containingDSA-OCn (n≥10) display more remarkable spectral shifts (46–53nm) than thosewith shorter alkyl chains (n≤9,14–20nm), suggesting that, to obtain remarkablePFC behaviour from9,10-bis(p-alkoxystyryl)anthracene homologues, long peripheralaliphatic tails are needed to balance intermolecular π–π and aliphatic interactions. Thediffuse reflectance absorption and IR spectra evidence that the more twistedconjugated backbones of DSA-OCn with long alkyl chains in unground state becomeless twisted by grinding, which, not the existence of liquid crystal phase and thegrinding-induced peak change should be responsible for the chain length-dependentPFC behaviour and the different grinding-induced spectral shift. The crystalline longalkyl-containing DSA-OCn exhibiting remarkable PFC behaviour may be promisingmaterials applicable in optical recording and sensing.2We have investigated the solution and aggregation fluorescence properties andPFC behavior of9,10-bis(alkoxystyryl)anthracene (OCn) derivatives with differentlength of alkoxy chains (propoxy, heptyloxy, and hexadecyl-oxy) linked at para-, ortho-and meta-positions of phenyl rings. These OCn derivatives show linkingposition-dependent solution and aqueous dispersion fluorescence properties, and theirPFC behaviors are both chain length-dependent and position-dependent. UnlikepOCn reported previously, we find that short alkyl-containing oOC3and mOC3exhibit more remarkable PFC activity, which is related to their strongly conjugatedbackbone conformations and weak inter-molecular interactions. These findingssuggest that changing the nature and linking position of substituents at peripheral arylrings of9,10-bis(arylvinyl)anthracenes can alter the molecular backboneconformation and solid-state packing structure to afford unique optical properties.