In the present work, the molecular structures of two new synthesized dyes：（4,6-dimethylpyrimidin-2-ylamino）（5-p-tolylisoxazol-3-yl）methanol（PS-1） and N-（4,6-dimethylpyrimidin-2-yl）-5-phenylisoxazole-3-carboxa...In the present work, the molecular structures of two new synthesized dyes：（4,6-dimethylpyrimidin-2-ylamino）（5-p-tolylisoxazol-3-yl）methanol（PS-1） and N-（4,6-dimethylpyrimidin-2-yl）-5-phenylisoxazole-3-carboxamide（PS-2）, have been investigated using density functional theory（DFT） in dimethylformamide（DMF） for the first time. The electronic spectra of new dyes in a DMF solvent were carried out by time dependent density functional theory（TD-DFT） method. After quantum-chemical calculations two new dyes for the optoelectronic applications were synthesized. FT-IR spectra of the title compounds are recorded and discussed. NucleusIndependent Chemical Shifts（NICS） calculations have also been carried out for the title compounds. The computed absorption spectral data of the title compounds are in good agreement with the experimental data, thus allowing an assignment of the UV spectra. The HOMO and LUMO molecular orbitals, excitation energies and oscillator strengths for the dyes have also been calculated and presented.展开更多
Rocky desertification has become a major environmental issue in the karst region of southwestern China.Karst rocky desertification was more severe in regions of limestone soil than in adjacent regions of other soils,d...Rocky desertification has become a major environmental issue in the karst region of southwestern China.Karst rocky desertification was more severe in regions of limestone soil than in adjacent regions of other soils,despite the relatively higher soil organic matter(SOM)content in limestone soil.The underlying mechanism remains ambiguous.We speculated that the geochemical characteristics of limestone soils in the karst region plays an essential role,especially the high calcium content of limestone soil.To test this hypothesis,we collected limestone soil samples from a limestone soil profile in the southwestern China karst region and extracted humic acid(HA)from these limestone soil samples.We investigated the interaction of Ca^(2+)and three HA samples on a joint experimental platform,which consists of an automatic potentiometric titrator,a UV–visible spectrometer,and a Fluorescence spectrometer.HA solutions were titrated by Ca^(2+)and optical spectra of the HA solutions were monitored during the titration experiments.The results indicated that:(1)the interaction of Ca^(2+)and HA is a combined process of adsorption and complexation.Adsorption dominated the overall distribution behavior of Ca^(2+),which could be fit by Langmuir and Freundlich isotherm models.Complexation was distinguished only when the concentration of Ca2+is low;(2)the changes of UV–visible spectroscopy and excitation–emission matrix fluorescencespectroscopy spectra of HA samples when they were binding with Ca^(2+)implied the apparent molecular size and structure of HA became larger and more complex;(3)the combination of Ca^(2+)and HA plays an important role in the SOM preservation of limestone soils but the stability of the Ca–HA association was relatively weak.The present study draws attention to maintaining the relatively higher Ca^(2+)concentration in limestone soils in ecologic restoration attempts in karst regions.展开更多
A new coordination polymer [Cu2(OH)(nbta)(tib)(H2 O)2]n(1, H3 nbta = 5-nitro-1,2,3-benzenetricarboxylic acid, tib = 1-(4 H-1,2,4-triazol-4-yl)-4-(imidazol-1-yl)benzene) constructed from dimeric Cu(Ⅱ) units has been s...A new coordination polymer [Cu2(OH)(nbta)(tib)(H2 O)2]n(1, H3 nbta = 5-nitro-1,2,3-benzenetricarboxylic acid, tib = 1-(4 H-1,2,4-triazol-4-yl)-4-(imidazol-1-yl)benzene) constructed from dimeric Cu(Ⅱ) units has been synthesized under hydrothermal conditions and structurally characterized by single-crystal X-ray diffraction analysis. The compound crystallizes in monoclinic system, space group I2/c, with a = 17.8474(9), b = 11.7588(6), c = 21.9221(11) ?, β = 104.419(5)°, V = 4455.7(4) ?3 and Z = 8. Compound 1 is a three-dimensional structure constructed from dimeric Cu(Ⅱ) units and presents a 2-nodal(3,5)-connected net. Moreover, the thermal stability and solid UV-Vis absorption spectra have been investigated.展开更多
In the given research,the molecular structures of two new compounds,4-((E)-3-(dimethylamino)styryl)-6-((E)-4-(dimethylamino)styryl)pyrimidine-2-amine(PM-1)and N-(4-((E)-3-(dimethylamino)styryl)-6-((E)-4-(dimethylamino...In the given research,the molecular structures of two new compounds,4-((E)-3-(dimethylamino)styryl)-6-((E)-4-(dimethylamino)styryl)pyrimidine-2-amine(PM-1)and N-(4-((E)-3-(dimethylamino)styryl)-6-((E)-4-(dimethylamino)styryl)pyrimidine-2-yl)-4,6-dichloro 1,3,5-1,3,5-triazin-2-amine(PM-2),have been studied with the use of density functional theory(DFT/B3LYP/MidiX)in dimethylformamide(DMF)for the first time.The electronic spectra of the new compounds in a DMF solvent were carried out by temporally dependent density functional theory(TD-DFT)method.The computed absorption spectral data of the title compounds are in good agreement with the experimental data,thus allowing an assignment of the UV/Vis spectra.The equilibrium geometry,the HOMO and LUMO molecular orbitals,excitation energies,oscillator strengths and Natural Bond Orbital(NBO)analysis for the molecules have also been calculated and presented.FT-IR spectra of the title molecules are recorded and discussed.The electron location function(ELF),localized orbital locator(LOL)and quantum theory of atoms in molecules(QTAIM)analyses were also carried out.On the basis of polyvinyl alcohol(PVA)and synthesized molecules,polarizer for UV/Vis region of the spectrum has been developed.展开更多
Aqueous lead monosulfide(PbS)quantum dots(QDs)fabricated by conventional approaches display poor photodetection performance and unsatisfactory chemical stability,so various strategies for well-defined PbS QD-based het...Aqueous lead monosulfide(PbS)quantum dots(QDs)fabricated by conventional approaches display poor photodetection performance and unsatisfactory chemical stability,so various strategies for well-defined PbS QD-based heterostructures have been developed,which are usually complicated and unsuitable for largescale production.In this work,homogeneous ultrasmall,uniform ternary Pb_(1−x)Cd_(x)S QDs are rationally designed and successfully fabricated by an in situ aqueous coprecipitation method.展开更多
Upconversion(UC)materials are recognized as promising candidates to harvest solar energy for photocatalysis.In this work,a simple strategy for simultaneously enhancing the UC luminescence and photocatalytic efficiency...Upconversion(UC)materials are recognized as promising candidates to harvest solar energy for photocatalysis.In this work,a simple strategy for simultaneously enhancing the UC luminescence and photocatalytic efficiency of BiOBr:Yb^(3+)/Er^(3+)nanoplates through Fe^(3+)ion doping is reported.Compared to the Fe^(3+)-free sample,the UC emission intensity was significantly enhanced through tailoring of the crystal symmetry by Fe^(3+)ions.Experiment and DFT calculations reveal that the introduction of Fe^(3+)ions resulted in the formation of an impurity energy level,extending to the light absorption region.As expected,the Fe^(3+)-doped BiOBr:Yb^(3+)/Er^(3+)nanoplates exhibit a wide photoresponse from the UV to NIR regions,good stability,and obviously enhanced photocatalytic activities compared with the BiOBr:Yb^(3+)/Er^(3+)nanoplates in the degradation of RhB.The boosted photocatalytic activity can be attributed to the synergic effect of the efficient utilization of UC luminescence and Fe^(3+)doping,where Fe^(3+)doping could improve the light harvesting capacity,enhance the separation efficiency of electron and hole(e−/h+)pairs,and promote the production of highly oxidative species.This work not only provides a promising system for the efficient utilization of solar light,but also offers a feasible guideline for the further design of broad-spectrum active photocatalysts.展开更多
Spin crossover(SCO)compounds are versatile platforms for incorporating functional ligands,enabling profuse magnetic regulating strategies and providing new likelihood for diversified practical applications of magneto-...Spin crossover(SCO)compounds are versatile platforms for incorporating functional ligands,enabling profuse magnetic regulating strategies and providing new likelihood for diversified practical applications of magneto-switches and information storage devices.Among the copious choices for stimuli-responsive ligands,diarylethene stands out as a photochromic unit that can be integrated into magnetic materials.Here,we report a triple interpenetrating SCO framework[Fe^(II)(Lo)_(2){Ag(CN)_(2)}_(2){Ag(CN)}_(2)](1,Lo=1,2-bis(2-methyl-5-(pyridin-4-yl)thiophen-3-yl)cyclopent-1-ene)with heterometallic nodes.Distinct from the conventional SCO frameworks in which Fe^(II) centers are directly bridged by organic ligands,the coordination fashion in 1 is manifested as Fe^(II)-Lo-Ag^(I)-Lo-Fe^(II).Photochromism is partially realized by the alternation of 365 nm and 520 nm light irradiation due to the tightly packed lattice.Subtle magnetic switching is observed from 1 to 1^(UV).Moreover,1^(UV) displays a photothermal response up to 162℃ under 808 nm light irradiation,with an enhancement in the photothermal conversion efficiency compared with that of 1.This thermally stable three-dimensional framework provides new structural possibilities for SCO polymers and takes a step forward in the assembly of UV-Vis-NIR responsive magnetic materials.展开更多
The authors regret that there were some errors in the original article.In the first paragraph of the Synthesis section in the Experimental section,in the sentence beginning“A 5 mL vial containing…”,the quantity of ...The authors regret that there were some errors in the original article.In the first paragraph of the Synthesis section in the Experimental section,in the sentence beginning“A 5 mL vial containing…”,the quantity of L_(o) was incorrectly given as“0.05 mmol,10.3 mg”.This should be“0.05 mmol,20.7 mg”.展开更多
In this work,the octaethyl-porphyrins with different central metals(M-OEP,M=Ni,VO,Cu,Co)were used to investigate the ground-state molecular structure,electron distribution and UV-spectra properties on molecular level ...In this work,the octaethyl-porphyrins with different central metals(M-OEP,M=Ni,VO,Cu,Co)were used to investigate the ground-state molecular structure,electron distribution and UV-spectra properties on molecular level by density functional theory(DFT).The results showed that the calculation structure parameters of metalloporphyrins agreed well with the experimental value.According to the Natural Bond Orbital(NBO)analysis,the charge distribution of different metalloporphyrins was found that the charge values of the central metal M decreased with the order of VO<Ni<Co<Cu,while the bonding strength between M and the coordinating atom N was VO>Ni>Co>Cu.At the same time,the frontier molecular orbital calculations showed that the SOMO energy of VO(OEP)molecules in the open-shell system was higher than that of Co(OEP)and Cu(OEP),which means that its UV absorption characteristic peak would be red-shifted.In addition,the IEFPCM model of Time-dependent Density functional theory(TD-DFT)was further utilized to simulate the four substance in toluene solution:Co(OEP),Ni(OEP),Cu(OEP)and VO(OEP),and the Soret band peaks were calculated respectively as:382 nm,383 nm,391 nm and 401 nm.Furthermore,the quantitative simulation analysis of metalloporphyrins was combined with experimental data.It could be found that the location rules of the four kinds of metalloporphyrins calculated absorption characteristic peaks were consistent with the experimental ones,and the relative errors of each peak were within 3%.These methods used above provide a theoretical path for analyzing and identifying unknown porphyrin compounds in petroleum.展开更多
Persistent luminescence is a unique optical phenomenon that continues to emit light for minutes or even hours after the excitation stops,which can significantly enhance the sensitivity and signal-to-noise ratio of ima...Persistent luminescence is a unique optical phenomenon that continues to emit light for minutes or even hours after the excitation stops,which can significantly enhance the sensitivity and signal-to-noise ratio of imaging[1].Among numerous persistent luminescence materials,lanthanide-doped fluoride nanoparticles have shown tunable persistent luminescence across the UV-vis-NIR spectrum(200-1700 nm)under X-ray excitation and adjustable size,promising significant applications in deep-tissue imaging[2,3],security encryption,and data storage[4].In particular,those exhibiting NIR-II luminescence(1000-1700 nm)provide key advantages such as deeper tissue penetration,higher contrast,and minimal interference from biological autofluorescence.However,challenges such as low brightness and rapid signal decay,especially in the NIR-II region,limit their effectiveness in long-term monitoring,including tumor theranostics[5].Traditional approaches like size control and surface passivation yield only marginal improvements,underscoring the need for next-generation nanoparticles with superior NIR-II brightness.展开更多
基金supported by the National Academy of Sciences of Belarus
文摘In the present work, the molecular structures of two new synthesized dyes：（4,6-dimethylpyrimidin-2-ylamino）（5-p-tolylisoxazol-3-yl）methanol（PS-1） and N-（4,6-dimethylpyrimidin-2-yl）-5-phenylisoxazole-3-carboxamide（PS-2）, have been investigated using density functional theory（DFT） in dimethylformamide（DMF） for the first time. The electronic spectra of new dyes in a DMF solvent were carried out by time dependent density functional theory（TD-DFT） method. After quantum-chemical calculations two new dyes for the optoelectronic applications were synthesized. FT-IR spectra of the title compounds are recorded and discussed. NucleusIndependent Chemical Shifts（NICS） calculations have also been carried out for the title compounds. The computed absorption spectral data of the title compounds are in good agreement with the experimental data, thus allowing an assignment of the UV spectra. The HOMO and LUMO molecular orbitals, excitation energies and oscillator strengths for the dyes have also been calculated and presented.
基金supported by the National Natural Science Foundation of China (U1701241, U1612441,41773147, and 41273149)the Science Foundation of Guizhou(20113109) 。
文摘Rocky desertification has become a major environmental issue in the karst region of southwestern China.Karst rocky desertification was more severe in regions of limestone soil than in adjacent regions of other soils,despite the relatively higher soil organic matter(SOM)content in limestone soil.The underlying mechanism remains ambiguous.We speculated that the geochemical characteristics of limestone soils in the karst region plays an essential role,especially the high calcium content of limestone soil.To test this hypothesis,we collected limestone soil samples from a limestone soil profile in the southwestern China karst region and extracted humic acid(HA)from these limestone soil samples.We investigated the interaction of Ca^(2+)and three HA samples on a joint experimental platform,which consists of an automatic potentiometric titrator,a UV–visible spectrometer,and a Fluorescence spectrometer.HA solutions were titrated by Ca^(2+)and optical spectra of the HA solutions were monitored during the titration experiments.The results indicated that:(1)the interaction of Ca^(2+)and HA is a combined process of adsorption and complexation.Adsorption dominated the overall distribution behavior of Ca^(2+),which could be fit by Langmuir and Freundlich isotherm models.Complexation was distinguished only when the concentration of Ca2+is low;(2)the changes of UV–visible spectroscopy and excitation–emission matrix fluorescencespectroscopy spectra of HA samples when they were binding with Ca^(2+)implied the apparent molecular size and structure of HA became larger and more complex;(3)the combination of Ca^(2+)and HA plays an important role in the SOM preservation of limestone soils but the stability of the Ca–HA association was relatively weak.The present study draws attention to maintaining the relatively higher Ca^(2+)concentration in limestone soils in ecologic restoration attempts in karst regions.
基金supported by the National Natural Science Foundation of China(21401097)
文摘A new coordination polymer [Cu2(OH)(nbta)(tib)(H2 O)2]n(1, H3 nbta = 5-nitro-1,2,3-benzenetricarboxylic acid, tib = 1-(4 H-1,2,4-triazol-4-yl)-4-(imidazol-1-yl)benzene) constructed from dimeric Cu(Ⅱ) units has been synthesized under hydrothermal conditions and structurally characterized by single-crystal X-ray diffraction analysis. The compound crystallizes in monoclinic system, space group I2/c, with a = 17.8474(9), b = 11.7588(6), c = 21.9221(11) ?, β = 104.419(5)°, V = 4455.7(4) ?3 and Z = 8. Compound 1 is a three-dimensional structure constructed from dimeric Cu(Ⅱ) units and presents a 2-nodal(3,5)-connected net. Moreover, the thermal stability and solid UV-Vis absorption spectra have been investigated.
基金supported by the National Academy of Sciences of Belarus
文摘In the given research,the molecular structures of two new compounds,4-((E)-3-(dimethylamino)styryl)-6-((E)-4-(dimethylamino)styryl)pyrimidine-2-amine(PM-1)and N-(4-((E)-3-(dimethylamino)styryl)-6-((E)-4-(dimethylamino)styryl)pyrimidine-2-yl)-4,6-dichloro 1,3,5-1,3,5-triazin-2-amine(PM-2),have been studied with the use of density functional theory(DFT/B3LYP/MidiX)in dimethylformamide(DMF)for the first time.The electronic spectra of the new compounds in a DMF solvent were carried out by temporally dependent density functional theory(TD-DFT)method.The computed absorption spectral data of the title compounds are in good agreement with the experimental data,thus allowing an assignment of the UV/Vis spectra.The equilibrium geometry,the HOMO and LUMO molecular orbitals,excitation energies,oscillator strengths and Natural Bond Orbital(NBO)analysis for the molecules have also been calculated and presented.FT-IR spectra of the title molecules are recorded and discussed.The electron location function(ELF),localized orbital locator(LOL)and quantum theory of atoms in molecules(QTAIM)analyses were also carried out.On the basis of polyvinyl alcohol(PVA)and synthesized molecules,polarizer for UV/Vis region of the spectrum has been developed.
基金supported by the National Natural Science Foundation of China(grant no.61805147 and 52103316).
文摘Aqueous lead monosulfide(PbS)quantum dots(QDs)fabricated by conventional approaches display poor photodetection performance and unsatisfactory chemical stability,so various strategies for well-defined PbS QD-based heterostructures have been developed,which are usually complicated and unsuitable for largescale production.In this work,homogeneous ultrasmall,uniform ternary Pb_(1−x)Cd_(x)S QDs are rationally designed and successfully fabricated by an in situ aqueous coprecipitation method.
基金supported by the National Natural Science Foundation of China(No.61172027)the Guangdong Natural Science Foundation(No.2014A030311049)the Science and Technology Planning Project of Guangdong Province(No.2017A010103035).
文摘Upconversion(UC)materials are recognized as promising candidates to harvest solar energy for photocatalysis.In this work,a simple strategy for simultaneously enhancing the UC luminescence and photocatalytic efficiency of BiOBr:Yb^(3+)/Er^(3+)nanoplates through Fe^(3+)ion doping is reported.Compared to the Fe^(3+)-free sample,the UC emission intensity was significantly enhanced through tailoring of the crystal symmetry by Fe^(3+)ions.Experiment and DFT calculations reveal that the introduction of Fe^(3+)ions resulted in the formation of an impurity energy level,extending to the light absorption region.As expected,the Fe^(3+)-doped BiOBr:Yb^(3+)/Er^(3+)nanoplates exhibit a wide photoresponse from the UV to NIR regions,good stability,and obviously enhanced photocatalytic activities compared with the BiOBr:Yb^(3+)/Er^(3+)nanoplates in the degradation of RhB.The boosted photocatalytic activity can be attributed to the synergic effect of the efficient utilization of UC luminescence and Fe^(3+)doping,where Fe^(3+)doping could improve the light harvesting capacity,enhance the separation efficiency of electron and hole(e−/h+)pairs,and promote the production of highly oxidative species.This work not only provides a promising system for the efficient utilization of solar light,but also offers a feasible guideline for the further design of broad-spectrum active photocatalysts.
基金supported by the NSFC(Grant No.22488101)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(23ptpy73)Science and Technology Program of Guangzhou,China(2024A04J4433).
文摘Spin crossover(SCO)compounds are versatile platforms for incorporating functional ligands,enabling profuse magnetic regulating strategies and providing new likelihood for diversified practical applications of magneto-switches and information storage devices.Among the copious choices for stimuli-responsive ligands,diarylethene stands out as a photochromic unit that can be integrated into magnetic materials.Here,we report a triple interpenetrating SCO framework[Fe^(II)(Lo)_(2){Ag(CN)_(2)}_(2){Ag(CN)}_(2)](1,Lo=1,2-bis(2-methyl-5-(pyridin-4-yl)thiophen-3-yl)cyclopent-1-ene)with heterometallic nodes.Distinct from the conventional SCO frameworks in which Fe^(II) centers are directly bridged by organic ligands,the coordination fashion in 1 is manifested as Fe^(II)-Lo-Ag^(I)-Lo-Fe^(II).Photochromism is partially realized by the alternation of 365 nm and 520 nm light irradiation due to the tightly packed lattice.Subtle magnetic switching is observed from 1 to 1^(UV).Moreover,1^(UV) displays a photothermal response up to 162℃ under 808 nm light irradiation,with an enhancement in the photothermal conversion efficiency compared with that of 1.This thermally stable three-dimensional framework provides new structural possibilities for SCO polymers and takes a step forward in the assembly of UV-Vis-NIR responsive magnetic materials.
文摘The authors regret that there were some errors in the original article.In the first paragraph of the Synthesis section in the Experimental section,in the sentence beginning“A 5 mL vial containing…”,the quantity of L_(o) was incorrectly given as“0.05 mmol,10.3 mg”.This should be“0.05 mmol,20.7 mg”.
基金the supports from the National Natural Science Foundation of China(21822810,21476260,and 21838011).
文摘In this work,the octaethyl-porphyrins with different central metals(M-OEP,M=Ni,VO,Cu,Co)were used to investigate the ground-state molecular structure,electron distribution and UV-spectra properties on molecular level by density functional theory(DFT).The results showed that the calculation structure parameters of metalloporphyrins agreed well with the experimental value.According to the Natural Bond Orbital(NBO)analysis,the charge distribution of different metalloporphyrins was found that the charge values of the central metal M decreased with the order of VO<Ni<Co<Cu,while the bonding strength between M and the coordinating atom N was VO>Ni>Co>Cu.At the same time,the frontier molecular orbital calculations showed that the SOMO energy of VO(OEP)molecules in the open-shell system was higher than that of Co(OEP)and Cu(OEP),which means that its UV absorption characteristic peak would be red-shifted.In addition,the IEFPCM model of Time-dependent Density functional theory(TD-DFT)was further utilized to simulate the four substance in toluene solution:Co(OEP),Ni(OEP),Cu(OEP)and VO(OEP),and the Soret band peaks were calculated respectively as:382 nm,383 nm,391 nm and 401 nm.Furthermore,the quantitative simulation analysis of metalloporphyrins was combined with experimental data.It could be found that the location rules of the four kinds of metalloporphyrins calculated absorption characteristic peaks were consistent with the experimental ones,and the relative errors of each peak were within 3%.These methods used above provide a theoretical path for analyzing and identifying unknown porphyrin compounds in petroleum.
基金supported by the Major Research Plan of the National Natural Science Foundation of China(No.92361202)National Natural Science Foundation of China(No.12204481).
文摘Persistent luminescence is a unique optical phenomenon that continues to emit light for minutes or even hours after the excitation stops,which can significantly enhance the sensitivity and signal-to-noise ratio of imaging[1].Among numerous persistent luminescence materials,lanthanide-doped fluoride nanoparticles have shown tunable persistent luminescence across the UV-vis-NIR spectrum(200-1700 nm)under X-ray excitation and adjustable size,promising significant applications in deep-tissue imaging[2,3],security encryption,and data storage[4].In particular,those exhibiting NIR-II luminescence(1000-1700 nm)provide key advantages such as deeper tissue penetration,higher contrast,and minimal interference from biological autofluorescence.However,challenges such as low brightness and rapid signal decay,especially in the NIR-II region,limit their effectiveness in long-term monitoring,including tumor theranostics[5].Traditional approaches like size control and surface passivation yield only marginal improvements,underscoring the need for next-generation nanoparticles with superior NIR-II brightness.
