Synthesis And Property Study Of O-Doped Pentacenes And Nonacenes

As one of the most widely studied organic?-functional materials,acenes are widely used in organic dyes,organic field effect transistors?OFETs?,organic photovoltaic devices?OPVs?,organic light emitting diodes?OLEDs?,organic memory devices and other fields.In order to explore these functional molecules and corresponding properties,scientists usually design them by either varying the functional groups,or extending the?-conjugated structure via increase of the number of linearly fused benzene rings.As we all known,acene compounds have unique optoelectronic properties with the expansion of?-conjugation structures.However,longer acenes make them unstable,and generally sensitive to light and oxygen.Thus,it is difficult to characterize high-order series well due to the high HOMO energy level.Besides,the issues,including the bandgap and transport properties should be taken into account.Alternatively,heteroatom is incorporated into acene framework,which avoids the rapid change of the stability with the length increase.The type/location/number of heteroatoms will provide us with more means to adjust the HOMO-LUMO gap,as well as the HOMO electron distribution.Therefore,accuratly-doped compounds with heteroatom,like O,S,B,N,etc.have attracted great attentions,especially for oxgen atoms due to their lone pair electron and electronegativity.In this work,we first take use of a phenolic condensation reaction between a simple organic molecule 1,4-dihydroxybenzene and a 2,6-dichlorobenzaldehyde,and a seriesofO-dopedaceneswereprovided.Thesemoleculesprocess p-quinodimethane-type of oxgen-doped skeleton.The results show that linear compounds with both symmetrical and asymmetrical terminal ends,namely,AOP-OH,SOP-OH,AON-OH,and SON-OH.Longer compounds may produce,however,they can not separated by common methord due to poor solubility.In addition,all conpounds bearing hydroxyl group can be easily modified by nucleophilic substitution reaction such as CH₃I,and afford the interesting acece derivatives,such as AOP-OMe,SOP-OMe,AON-OMe and SON-OMe.It seems that the introduction of methyl groups makes them solubility better.Consequently,we characterized the molecular structure by means of by ¹H NMR,¹³C NMR spectroscopy,MALDI-TOF mass spectrometry and X-ray single crystal analysis.Their properties were also studied by various experimental methods including the UV-vis-NIR,Fluorescence Spectrometer,Cyclic Voltammetry?CV?and X-ray single crystal diffractometer.