Benzoyl chloride and spiro-9，9′-xanthene were used as starting materials， and anhydrous AlCl₃ was employed as a catalyst. Then， the compound 2′-（benzoyl）-spiro-9，9′-xanthene （SFXBz） was synthesized facilely by Friedel-Crafts reaction. The crystal structure of SFXBz revealed that the three-dimensional spatial structure of spirocyclic carbonyl compound could suppress the intermolecular interactions effectively. It exhibited a high thermal decomposition temperature （T_d） of 314 ℃， which was significantly higher than that of spiro［fluorene-9，9'-xanthene （SFX， T_d， 258 ℃） and phenyl sulfone-functionalized SFX （PSSFX， 2'-（phenylsulfonyl）spiro［fluorene-9，9'-xanthene］， T_d： 222 ℃）， indicating that the introduction of a rigid benzoyl moiety could improve the thermal stability of SFX effectively. The differential scanning calorimetry （DSC） curve of SFXBz showed that there was no phase transition when the temperature increased from 40 ℃ to 220 ℃ with a high melting point of 202 ℃. Both of the thermogravimetric analysis （TGA） and DSC results of SFXBz indicated that the compound had high thermal stability and stable morphology. The density functional theory （DFT） calculations showed that the highest molecular orbital （HOMO） and the lowest unoccupied molecular orbital （LUMO） of SFXBz were separated completely， with energy levels of -5.82 eV and -1.58 eV， respectively. The spatially separated HOMO and LUMO orbitals of SFXBz indicated the compound owned bipolar characteristics. The HOMO and LUMO energy levels of SFXBz were further measured by cyclic voltammetry， the values of which were -6.22 eV and -1.97 eV， respectively. The deep HOMO energy level of SFXBz was favorable for blocking hole injection and transportion. The UV-absorption and photoluminescence spectrum of the compound showed that the main absorption peaks were at 229 nm， 273 nm， 299 nm， 309 nm， and 348 nm， respectively， and its maximum fluorescence emission peak was around 374 nm. The triplet energy level （2.55 eV） of the compound was obtained from the low-temperature phosphorescence spectroscopy， which was higher than those of the classic red and green guest materials （2，4-pentanedionato）bis［2-（2-quinolinyl）phenyl］iridium（Ⅲ） （Ir（pq）₂acac， T₁， 2.10） and fac-Tris［2-phenylpyridinato-C2，N］iridium（Ⅲ） （Ir（PPy）₃， T₁， 2.40 eV）， respectively. This indicated that the compound could be used as a host material for red and green phosphorescent devices.

Spiro［fluorene-9;9'-xanthene］;facile synthesis