查看更多>>摘要：The in situ preparation and the full spectroscopic characterization of corrole-gold nanoparticles(AuTPFCS)are reported.The synthetic approach to these nanoconjugates involved the reaction of a mercaptocorrole(TPFCSH)with chloroauric acid under reductive conditions.Fluorescence quantum yields and time resolved lifetimes showed a significant quenching of the mercaptocorrole after its covalent coupling to the gold nanoparticles in acetonitrile and in toluene.Irradiated samples of AuTPFCS with a Nd:YAG laser in toluene solution revealed the distribution of larger nanoparticles from 3.1 to 11 nm viewed by TEM images.
查看更多>>摘要：The synthesis and photochemical properties of six new lipophilic chalcogen tetrasubstituted zinc(II)phthalo-cyanines and their corresponding water-soluble cationic derivatives were investigated for CT26 colon carcinoma cells photodynamic therapy.Sulfur and selenium phthalocyanines Q-bands are red shifted around 10 nm with respect to the Q-band of oxygen phthalocyanines.The introduction of Se atoms in peripheral position generates non-significant shifts in the absorption spectrum compared to S-bearing phthalocyanine.In addition,Q-band absorption coefficient of selenium phthalocyanines showed to be higher than their respective sulfur and oxygen analogs,which is relevant for dosing in PDT studies.The fluorescence emission maximum wavelength showed the same trend regards to the presence of chalcogen atoms,O < Se < S.All phthalocyanines are efficient singlet oxygen generators with values in the range 0.42-0.75.In most cases,increasing the atomic number of chalcogen atoms produces a rise of singlet oxygen production efficiency.The replacement of O for S or Se atoms cause a red shifting around 20 nm of triplet-triplet maximum absorption wavelength and the introduction of Se atoms causes a significant shortening of τT.The photodynamic effect was evaluated on CT26 colon carcinoma cells.Oxygen phthalocyanines triggered cell death both in the absence or presence of light,whereas sulfur and selenium phthalocyanines diminished cell viability in a concentration dependent manner only after light exposure.S-bearing phthalocyanines showed the best photodynamic efficiency among all novel phthalocyanines.
查看更多>>摘要：We prepared a series of D-A-D'type random copolymers,which are based on PBDB-S-3Cl and PBDB-S-4Cl,PBDB-S-CO-3Cl-4Cl(1:9),PBDB-S-CO-3Cl-4Cl(3:7),PBDB-S-CO-3Cl-4C1(7:3)and PBDB-S-CO-3Cl-4Cl(9:1)with 3-chloro or 4-chloro and 2-s-alkylated thiophene on benzodithiophene(BDT),to examine the position effects of chlorine substitution of PBDB-S on its photovoltaic performance in organic photovoltaics(OPVs).The modulation of composition of random copolymer with the position effects of chlorine substitution affect the performance of organic photovoltaic(OPV)devices.The PBDB-S-CO-3Cl-4Cl(9:1)random copolymer-based OPV devices exhibit the highest power conversion efficiency(PCE)of 13.31%,and fill factor(FF)of 0.63,which was higher performance than those of homopolymer PBDB-S-3C1 and PBDB-S-4Cl.
查看更多>>摘要：Smith et al.recently reported dye analysis of a carpet fragment thought by some to be from a 15th century silk-knotted Persian carpet [Smith et al,Forensic Science International:Synergy 2021;3:100130].Sample threads were found to contain several synthetic dyes from the late 19th century,including Congo red,which was first synthesized in 1883,indicating that the carpet is a modern object.Two mysterious compounds designated as A and B of unknown identity were also detected with Congo red in similar amounts on the object.This paper reports the structural elucidation of A and B using high resolution mass spectrometry and multidimensional NMR spectroscopy.To our knowledge,these compounds have never been reported before.Additionally,experiments are described demonstrating that A and B were products from the reaction of Congo red with formaldehyde.Previously unknown homologs of A and B were also formed when Congo red was reacted with acetaldehyde,pentanal,and hexanal,indicating a common reaction mechanism.Uv-Vis spectra of the homologs suggest that aldehyde exposure can cause an overall color change in objects dyed with Congo red.A historic dye swatch book containing cotton skeins dyed with the colorants benzopurpurine 4B and deltapurpurine 5B,which are of the same chemical class as Congo red,and exhibiting a faded appearance,were found to contain dye derivatives analogous to A and B.Chemical mechanisms proposed for the formation of compounds A and B are discussed,along with the possible origins of the formaldehyde exposure.The concept of'chemical fading,'is adduced to heighten the awareness of the exposure of historic dyed textiles to the harmful effects of formaldehyde,a common museum and household pollutant.
查看更多>>摘要：Herein we have synthesized and characterized the novel π-σ* conjugated l,4-bis(l-methyl-2,3,4,5-tetraphenyl-l-silacyclopentadienyl)benzene nanoaggregates based on aggregation-induced emission enhancement(AIEE)property for the detection of nitroaromatic compounds by fluorescence quenching.The new photoluminescent silole nanoaggregates exhibited unique AIEE property by increasing the emission intensity 180 times in THF/water mixtures.We investigated that the π-σ* hyper conjugation of Si-C phenyl ring is more effective on AIEE due to the less non-radiative decay than the σ-σ* hyper conjugation of Si-Si bond of l,4-bis(l-methyl-2,3,4,5-tet-raphenyl-1-silacyclopentadienyl).The π-σ* conjugated nanoaggregates showed excellent sensitivity for sensing explosives.High Stern-Volmer constant was observed during quenching of photoluminescence(PL)intensity upon adding explosives.The absolute quantum yield and average particle size were measured for the nanoaggregates and tuned by controlling at different fraction of water.These results demonstrate that AIEE property of π-σ* conjugated silole nanoaggregates will provide guidance to develop fluorescent materials for detecting explosives.
查看更多>>摘要：A series of new luminescent lanthanide benzoates [Ln2(phen)2(bza)4(Ac)2] {Ln = Eu(1),Gd~(3+)(2),Tb~(3+)(3),Dy~(3+)(4),Tm~~(3+)(5);phen = 1,10-phenanthroline,Hbza = benzoic acid,Ac"= acetate)} and [Ln2(phen)2(b-za)4(NO3)2] [Ln = Sm~~(3+)(6),Eu~(~(3+))(7),Tb~(3+)(8),Dy~(3+)(9),Tm~~(3+)(10)] have been hydrothermaUy prepared by the usage of the n-conjugated phen ligands as chromophores.1-5 exhibit binuclear [Ln2(phen)2(bza)4(Ac)2] moieties built up from two [Ln(phen)]~(3+)groups joined together by the bridging bza~ and Ac~ ligands,while 6-10 show another binuclear [Ln2(phen)2(bza)4(NO3)2] moieties constructed by two [Ln(phen)(NO3)]~(2+)groups linked together by the bridging bza~ ligands.These compounds offer the rare examples of binuclear lanthanide benzoates decorated by phen chromophores.Luminescent and sensing properties of 1-10 were studied,revealing that europium(1 and 7)and terbium(3 and 8)benzoates can be used as a bifunctional luminescent probe for acetone and Fe~(3+)with high efficiency and selectivity.
查看更多>>摘要：Vanadyl phthalocyanine {V~(IV)O(Pc~(2-))}~0 was reduced by decamethylchromocene or decamethylcobaltocene(Cp*2M~(II)),and the crystals of the complexes were precipitated by n-hexane.Reduction of this phthalocyanine is centered on the macrocycle providing the formation of the {V~(IV)O(Pc~(·3-))}-anions containing two paramagnetic V~(IV)and Pc~(·3-)centers with an S = 1/2 spin state.These paramagnetic anions coexist in(Cp*2Cr+){VIvO(Pc~(·3-))}~-3C6H4Cl2(1)with the high-spin(S = 3/2)Cp*2Cr~+ counter cations.Nearly isolated assemblies in which two Cp*2Cr~+ cations are sandwiched between two {V~(IV)O(Pc~(·3-))}~-anions are formed in 1.Effective magnetic moment of 1 of 4.57 μB at 300 K corresponds to the contribution of noninteracting V~(IV),Pc~(·3-)and Gr~(III)spins.Weiss temperature of +4 K indicates weak ferromagnetic coupling of spins.Effective magnetic moment of 1 increases upon cooling up to 4.78 μB at 8 K and then drastically falls down.Such magnetic behavior is described well by ferromagnetic coupling between the V~(IV)and Pc~(·3-)spins with J1 = + 4.75 cm~(-1)and weaker ferro-magnetic interactions between Pc~(·3-)and Cr~(III)spins through the Cp* ligand with J2 = +1.08 cm~(-1).Weak anti-ferromagnetic coupling with J3 =-0.76 cm~(-1)is also present between the Cr~(III)spins.Complexes(Cp*2Co~+){V~(IV)O(Pc~(·3-))}~-·1.5C6H4C12(2)and(Cp*2Co~+){V~(IV)O(Pc~(·3-))}~-·C6H4Cl2(3)with the diamagnetic Cp*2Co~+ counter cations(S = 0)were also obtained allowing to study their crystal structures and optical properties.
查看更多>>摘要：The sensing of carboxylesterases(CESs)activity in living systems is of great importance for drug design and biomedical research.Herein,water-soluble AIE-active fluorescent organic nanoparticles(2B30Ts)containing hydrophilic lactose and hydrophobic BODIPY-conjugated tetraphenylethene moieties were rationally designed for ratiometrically fluorescent sensing of CESs with the meso-ester BODIPY as the recognition unit.2B30Ts were cell membrane permeable and successfully applied to detect the real activities of endogenous CESs in living cells.More importantly,2B3OTs could preferentially recognize hepatoma cells rather than normal liver cells,since the lactose is an efficient ligand for asialoglycoprotein receptors which are over expressed in tumor liver cells.It is first time that water-soluble AIE-active fluorescence organic nanoparticle were designed and utilized for realtime sensing of CESs activities in living cells.
查看更多>>摘要：A ratiometric fluorescence sensor based on Cu-CDs-COOH-Eu was proposed and used to highly sensitive detection of Tetracycline(TC)residues in complex samples.Combination with surface functionalization of carboxyl group and heteroatom doping of Cu~(2+),the bi-functional carbon dots(Cu-CDs-COOH)were prepared,which exhibited an outstanding fluorescence properties and optical stability.Thanks to the Cu-CDs-COOH rich in carboxyl groups,Eu~(3+)can effectively chelate with Cu-CDs-COOH which still maintained excellent optical properties(denoted as Cu-CDs-COOH-Eu).When TC was presented in the sensing system of Cu-CDs-COOH-Eu,the strong blue emission of Cu-COOH was quenched at 467 nm based on inner filter effect while the characteristic peak of Eu~(3+)at 625 nm was enhanced via antenna effect.Herein,a ratiometric fluorescence sensor was built,which was able to detect TC in the range of 0.4-60 μM with a low limit detection of 36.1 nM.The proposed method also showed a satisfactory result of determination TC reliably and accurately in complex samples.
查看更多>>摘要：Recently,Chen et al.reported an experimental result of photo-stability of a series of bis-tridentate Ir(III)phosphors(m~2h-2 and m6h)that the photo-stability of the Ir(III)phosphors strongly depends of bond strength between carbon in pyrimidine and pyrazole or phenyl fragment.In this report,the photo-,and electro-chemical stability at excited states of bis-tridentate Ir(III)phosphors were theoretically investigated by employing density functional theory(DFT)simulation.It was revealed that the most favorable geometry of triplet metal-centered(~3MC)state in bis-tridentate Ir(III)phosphors were originated from a ligand rupture of Ir-N bond at pyrimidine unit,where the calculated AE(~3MC-T1)values of m~2h-2 and m6h-2 phosphors were 0.06 eV and 0.23 eV,respectively and surprisingly,the rate constant of photo degradation of m~2h-2,m6h-2,and Ir(ppy)3 is linearly proportional to the AE(~3MC-T1)values.This result suggests that large ΔE(~3MC-T1)is the detrimental factor for chemical stability of high-energy Ir(III)phosphors.
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