Partial genetically encoded 4-hy-droxybenzylidene-imidazolinone(HBI)-type chromophores are new promising fluorescent probes,which are suitable for imaging and detection of living cells.How-ever,the lack of infrared ch...Partial genetically encoded 4-hy-droxybenzylidene-imidazolinone(HBI)-type chromophores are new promising fluorescent probes,which are suitable for imaging and detection of living cells.How-ever,the lack of infrared chro-mophores hinders the develop-ment seriously.Here more than 30 HBI-type chromophores with reg-ular structure modifications were employed and typical spectral redshift change laws and mechanisms were investigated by quantum methods.Results show that both one-photon spectrum(OPS,absorption/emission)and two-photon absorption(TPA)can achieve large redshift via either extending conjugated lengths of frag-3 or enlarging conjugated areas of frag-1 of HBI skeleton.Spectral redshifts of all chromophores are highly related to intramolecular charge transfer(ICT),but neutral ones are closely related to the total ICT or electron-accept-ing-numbers of frag-3,and the high correlative factor of anions is the aromaticity of frag-2 bridge.The frag-2 bridge with high aromaticity can open a reverse charge transfer channel in anion relative to neutral,obtaining significant redshift.Based on analysis,a new 6-hydroxyl-naphthalene-imidazolinone(HNI)series,which have larger conjugated area in frag-1,are pre-dicted.The OPS and TPA of anionic HNI ones acquire about 76−96 nm and 119−146 nm red-shift relative to traditional HBI series respectively as a whole.The longest emission of anionic HNI-4 realizes more 244 nm redshift relative to HBI-1.Our work clarifies worthy spectral reg-ularities and redshift mechanisms of HBI-type chromophores and provides valuable design strategy for infrared chromophores synthesis in experiment.展开更多
Revealing structural isomerization in metal clusters would bridge a huge structural gap between small molecular isomerization and solid–solid phase transformation.However,genuine structural isomerism in metal cluster...Revealing structural isomerization in metal clusters would bridge a huge structural gap between small molecular isomerization and solid–solid phase transformation.However,genuine structural isomerism in metal clusters is still rare.In this work,we report the first example of structural isomerismin Cu clusters.By utilizing the coordination flexibility of alkyne to enable the migration of partial Cu atoms in Cu metal cores,two Cu_(15)cluster complexes(Cu_(15)-a and Cu_(15)-c)possessing identical composition but different metal core structures have been successfully isolated.Interestingly,although the structure of Cu_(15)-a can be retained in CH_(2)C_(l2)solution below 27°C,it will gradually change to give an intermediate state,Cu_(15)-b,as the temperature rises(at about 31°C)before it eventually transforms into Cu_(15)-c(at 40∼65°C).Significantly,atomically precise Cu_(15)-b clearly provides footprints for tracing the thermal migration process of Cu atoms during the thermal transformation from Cu_(15)-a to Cu_(15)-c.In addition,Cu_(15)-a and Cu_(15)-c exhibit diverse crystallization-induced emission enhancement phenomena.Crystalline Cu_(15)-c displays redshifted photoluminescence(820 nm)compared with Cu_(15)-a(726 nm)due to the shorter mean Cu···Cu distance in Cu_(15)-c.Notwithstanding,crystalline Cu_(15)-a exhibits much more intense photoluminescence at room temperature than that in Cu_(15)-c,which might be attributed to the stronger intermolecular C–H⋯πinteractions in Cu_(15)-a.These results indicate that cluster isomerism provides valuable opportunities for insight into the structure–property relationships and understanding the complex evolution of phase transformation in nanometallic solids.展开更多
基金supported by the National Natural Sci-ence Foundation of China(No.U1904196,No.82073699)the Natural Science Foundation of Henan(No.222300420055).
文摘Partial genetically encoded 4-hy-droxybenzylidene-imidazolinone(HBI)-type chromophores are new promising fluorescent probes,which are suitable for imaging and detection of living cells.How-ever,the lack of infrared chro-mophores hinders the develop-ment seriously.Here more than 30 HBI-type chromophores with reg-ular structure modifications were employed and typical spectral redshift change laws and mechanisms were investigated by quantum methods.Results show that both one-photon spectrum(OPS,absorption/emission)and two-photon absorption(TPA)can achieve large redshift via either extending conjugated lengths of frag-3 or enlarging conjugated areas of frag-1 of HBI skeleton.Spectral redshifts of all chromophores are highly related to intramolecular charge transfer(ICT),but neutral ones are closely related to the total ICT or electron-accept-ing-numbers of frag-3,and the high correlative factor of anions is the aromaticity of frag-2 bridge.The frag-2 bridge with high aromaticity can open a reverse charge transfer channel in anion relative to neutral,obtaining significant redshift.Based on analysis,a new 6-hydroxyl-naphthalene-imidazolinone(HNI)series,which have larger conjugated area in frag-1,are pre-dicted.The OPS and TPA of anionic HNI ones acquire about 76−96 nm and 119−146 nm red-shift relative to traditional HBI series respectively as a whole.The longest emission of anionic HNI-4 realizes more 244 nm redshift relative to HBI-1.Our work clarifies worthy spectral reg-ularities and redshift mechanisms of HBI-type chromophores and provides valuable design strategy for infrared chromophores synthesis in experiment.
基金supported by the National Natural Science Foundation of China(grant nos.22101048,22005054,and 21975044)the Natural Science Foundation of Fujian Province(grant no.2021J01150).
文摘Revealing structural isomerization in metal clusters would bridge a huge structural gap between small molecular isomerization and solid–solid phase transformation.However,genuine structural isomerism in metal clusters is still rare.In this work,we report the first example of structural isomerismin Cu clusters.By utilizing the coordination flexibility of alkyne to enable the migration of partial Cu atoms in Cu metal cores,two Cu_(15)cluster complexes(Cu_(15)-a and Cu_(15)-c)possessing identical composition but different metal core structures have been successfully isolated.Interestingly,although the structure of Cu_(15)-a can be retained in CH_(2)C_(l2)solution below 27°C,it will gradually change to give an intermediate state,Cu_(15)-b,as the temperature rises(at about 31°C)before it eventually transforms into Cu_(15)-c(at 40∼65°C).Significantly,atomically precise Cu_(15)-b clearly provides footprints for tracing the thermal migration process of Cu atoms during the thermal transformation from Cu_(15)-a to Cu_(15)-c.In addition,Cu_(15)-a and Cu_(15)-c exhibit diverse crystallization-induced emission enhancement phenomena.Crystalline Cu_(15)-c displays redshifted photoluminescence(820 nm)compared with Cu_(15)-a(726 nm)due to the shorter mean Cu···Cu distance in Cu_(15)-c.Notwithstanding,crystalline Cu_(15)-a exhibits much more intense photoluminescence at room temperature than that in Cu_(15)-c,which might be attributed to the stronger intermolecular C–H⋯πinteractions in Cu_(15)-a.These results indicate that cluster isomerism provides valuable opportunities for insight into the structure–property relationships and understanding the complex evolution of phase transformation in nanometallic solids.
