The design of efficient aggregation-induced emission materials requires an improved understanding of photophysical processes in aggregated materials.Herein,the photophysical behavior of an Au(I)complex(R6)that exhibit...The design of efficient aggregation-induced emission materials requires an improved understanding of photophysical processes in aggregated materials.Herein,the photophysical behavior of an Au(I)complex(R6)that exhibits intense roomtemperature phosphorescence(RTP)in crystals is described.In addition,the photophysical processes related to RTP are discussed based on the structure of the molecular aggregates and the primary structure of the molecule.An extremely efficient S_(0)-T_(n) direct transition is found to occur in the R6 crystal.Furthermore,intermolecular Au-Au interactions and the internal/external heavy-atom effects of Au atoms are demonstrated to enhance the electronic transitions involving intersystem crossing,namely,direct S_(0)-T_(n) excitation,radiative T_(1)-S_(0) transition(phosphorescence),and S_(1)-T_(n) intersystem crossing.Because of the dense molecular packing,both Au-Au interactions and heavy-atom effects play important roles in the crystals.As a result,R6 shows more efficient RTP in crystals than in solution.These insights into the mechanism of highly efficient RTP in Au(I)-complex crystals are expected to advance the development of new luminogens for a variety of sensing and imaging applications.展开更多
Since the discovery of the triphenylmethyl(trityl)cation 120 years ago,a variety of aromatic cations having various colors and luminescence properties have been rigorously studied.Many,differently substituted trityl c...Since the discovery of the triphenylmethyl(trityl)cation 120 years ago,a variety of aromatic cations having various colors and luminescence properties have been rigorously studied.Many,differently substituted trityl cations have been synthesized,and their optical properties have been elucidated.However,the optical properties of the parent,non-substituted and highly reactive trityl cation,which was observed to be very weakly luminescent,have not been subjected to detailed investigation.In the effort described herein,we explored the optical nature of non-substituted trityl hexafluorophosphate(PF_(6))in the crystalline state.Trityl PF_(6) was found to exist as two crystal polymorphs including a yellow(Y)and an orange(O)form.Moreover,we observed that these crystalline forms display crystalline-state emission with different colors.The results of X-ray crystallographic analysis showed that the two polymorphs have totally different molecular packing arrangements.Furthermore,an investigation of their optical properties revealed that the O-crystal undergoes a distinct color change to yellow upon cooling as a consequence of a change in the nature of the charge transfer interaction between the cation and PF6 anion,and that both the Y-and O-crystal exhibit phosphorescence.展开更多
文摘The design of efficient aggregation-induced emission materials requires an improved understanding of photophysical processes in aggregated materials.Herein,the photophysical behavior of an Au(I)complex(R6)that exhibits intense roomtemperature phosphorescence(RTP)in crystals is described.In addition,the photophysical processes related to RTP are discussed based on the structure of the molecular aggregates and the primary structure of the molecule.An extremely efficient S_(0)-T_(n) direct transition is found to occur in the R6 crystal.Furthermore,intermolecular Au-Au interactions and the internal/external heavy-atom effects of Au atoms are demonstrated to enhance the electronic transitions involving intersystem crossing,namely,direct S_(0)-T_(n) excitation,radiative T_(1)-S_(0) transition(phosphorescence),and S_(1)-T_(n) intersystem crossing.Because of the dense molecular packing,both Au-Au interactions and heavy-atom effects play important roles in the crystals.As a result,R6 shows more efficient RTP in crystals than in solution.These insights into the mechanism of highly efficient RTP in Au(I)-complex crystals are expected to advance the development of new luminogens for a variety of sensing and imaging applications.
基金JSPSKAKENHI Grant-in-Aid for Scientific Research(C),Grant/Award Number:JP20K05475(Tomohiko Nishiuchi)Scientific Research(B),Grant/Award Number:JP21H01887(Kenji Kamada)。
文摘Since the discovery of the triphenylmethyl(trityl)cation 120 years ago,a variety of aromatic cations having various colors and luminescence properties have been rigorously studied.Many,differently substituted trityl cations have been synthesized,and their optical properties have been elucidated.However,the optical properties of the parent,non-substituted and highly reactive trityl cation,which was observed to be very weakly luminescent,have not been subjected to detailed investigation.In the effort described herein,we explored the optical nature of non-substituted trityl hexafluorophosphate(PF_(6))in the crystalline state.Trityl PF_(6) was found to exist as two crystal polymorphs including a yellow(Y)and an orange(O)form.Moreover,we observed that these crystalline forms display crystalline-state emission with different colors.The results of X-ray crystallographic analysis showed that the two polymorphs have totally different molecular packing arrangements.Furthermore,an investigation of their optical properties revealed that the O-crystal undergoes a distinct color change to yellow upon cooling as a consequence of a change in the nature of the charge transfer interaction between the cation and PF6 anion,and that both the Y-and O-crystal exhibit phosphorescence.
