Triphenylamine (TPA) – acetophenone donor-π-acceptor fluorophore with halogen (F, Cl and Br) substitution was synthesized and explored the influence of halogen atom on the solution as well as solid-state fluorescence properties. The unsubstituted 1 ((E)-3-(4-(diphenylamino) phenyl)-1-phenylprop-2-en-1-one) exhibited strong fluorescence in non-polar solvents but weak fluorescence in polar solvents. The halogen substitution (4F ((E)-3-(4-(diphenyl amino)phenyl)-1-(4-fluorophenyl)prop-2-en-1-one), 4Cl ((E)-3-(4-(diphenylamino)phenyl)-1-(4-chlorophenyl)prop-2-en-1-one) and 4Br ((E)-3-(4-(diphenylamino)phenyl)-1-(4-bromo phenyl)prop-2-en-1-one)) significantly influenced on the fluorescence both in solution as well as solid-state. 1 showed white light emission in polar methanol but 4F and 4Cl exhibited white light emission in polar as well as non-polar solvents. 4Br showed white light emission in CH₃CN. Solid-state structural studies of 1 revealed the formation of interconnected dimers via intermolecular H-bonding between carbonyl oxygen and TPA phenyl hydrogens. Though 4F also exhibited dimer via H-bonding of carbonyl oxygen, the dimers are interconnected by π … π interaction of TPA phenyls. The Br … π interaction produced 1D structure in the crystal lattice of 4Br that was further interconnected by multiple intermolecular interactions. The molecular conformational and packing modification of 1 and halogen isomers produced tunable fluorescence between 522 and 593 nm. Interestingly, only 4Br showed clear external stimuli-induced reversible/self-reversible fluorescence switching between two fluorescence states. The fluorescence was red shifted with slight reduction of intensity while crushing and heating/solvent exposure caused recovering of fluorescence. Powder X-ray diffraction of 4Br indicated the reversible phase transition was responsible for stimuli-induced reversible fluorescence switching. Thus, the present studies utilized the halogen atom to tune the fluorescence and studied its role on the fluorescence switching and white light emission.

合成了具有卤素（F、Cl 和 Br）取代的三苯胺 (TPA) - 苯乙酮供体-π-受体荧光团，并探索了卤素原子对溶液的影响以及固态荧光特性。未取代的1 ((E)-3-(4-(diphenylamino) phenyl)-1-phenylprop-2-en-1-one) 在非极性溶剂中表现出强荧光，但在极性溶剂中表现出弱荧光。卤素取代( 4F ((E)-3-(4-(二苯基氨基)苯基)-1-(4-氟苯基)prop-2-en-1-one), 4Cl ((E)-3-(4 -(二苯基氨基)苯基)-1-(4-氯苯基)prop-2-en-1-one)和4Br ((E)-3-(4-(二苯基氨基)苯基)-1-(4-溴苯基) prop-2-en-1-one)) 显着影响溶液和固态的荧光。1在极性甲醇中显示白光发射，但4F和4Cl在极性和非极性溶剂中显示白光发射。4Br在CH ₃ CN中显示出白光发射。1的固态结构研究揭示了通过羰基氧和 TPA 苯基氢之间的分子间氢键形成相互连接的二聚体。虽然4F也通过羰基氧的氢键表现出二聚体，但二聚体通过 TPA 苯基的 π … π 相互作用相互连接。Br … π 相互作用在4Br的晶格中产生一维结构通过多种分子间相互作用进一步相互联系。1和卤素异构体的分子构象和堆积修饰产生了 522 和 593 nm 之间的可调谐荧光。有趣的是，只有4Br显示出明显的外部刺激诱导的可逆/自可逆荧光在两种荧光状态之间切换。荧光发生红移，强度略有降低，而粉碎和加热/溶剂暴露导致荧光恢复。4Br的粉末X射线衍射表明可逆相变是刺激诱导的可逆荧光切换的原因。因此，本研究利用卤素原子调谐荧光，研究其在荧光切换和白光发射中的作用。