Separation of Aromatic Carboxylic Acids in IC and the Study on the Relationship Between Retention Behavior and Electrostatic Potential

A method has been developed for separation of 20 kinds of aromatic carboxylic acid using anion-exchange chromatography. A Dionex IonPac AS9-HC guard column （250mm×2mm） was used with a 9mmol/L sodium carbonate solution containing 50% （v/v） acetonitrile as eluent. A set of retention time data has been obtained using a conductivity detector DS6. Furthermore, geometrical optimization and electrostatic potential calculation of 20 kinds of aromatic carboxylic acid have been performed at the HF/6-31G＊ level of theory. A number of statistically-based parameters derived from molecular surface electrostatic potential have been obtained. Linear relationship between retention time and structural parameters has been established by multiple regression method. The result shows that parameters derived from electrostatic potential Vs ＋, Vs -, П together with the dipole moment μ can be well used to express the quantitative structure-retention time of this kind of aromatic carboxylic acid. Good predictive capability has also been demonstrated. The result has provided a framework which further proves the general applicability of this electrostatic potential parameter set to a great extent,and with which the ion chromatographic adsorption mechanism can be investigated.

A novel strategy for high-specificity, high-sensitivity, and high-throughput study for gut microbiome metabolism of aromatic carboxylic acids

Aromatic carboxylic acids(ACAs) may be as transformed key metabolites via gut microbiome for playing better pharmacological effects. However, it's rare to achieve high-specificity, high-sensitivity, and highthroughput detection simultaneously, especially, for tracing trace ACAs in gut microbiome. In this work,firstly, a novel dual-template and double-shelled molecularly imprinted 96-well microplates(DDMIPs)was designed and amplified signal for p-hydroxybenzoic acid(PBA) and 3,4,5-trimethoxycinnamic acid(TMA). Additionally, the DDMIPs and a stable isotope labeling derivatization(SILD) method combined with the ultra-high performance liquid chromatography triple quadrupole tandem mass spectrometry(UHPLC-TQ MS) was firstly stepwise integrated, achieving high-effective, high-sensitive, and highthroughput study of gut microbiome metabolism. The whole strategy showed lower limits of detections(LODs) up to 1000 folds than the traditional method, and revealed a more real metabolism-time profile of PBA and TMA by 3-step signal amplification. The platform also laid the foundation for fast, simple,high-selective, high-effective, and high-throughput metabolism and pharmacological research.

Synthesis and Properties of Ternary Europium Complexes with Aromatic Carboxylic Acid and Nitrogen-Containing Heterocyclic Ligand

Seven ternary Eu （m） complexes were synthesized with aromatic carboxylic acid （benzoic acid, phenylacetic acid, phenylpropionic acid and cinnamic acid） as the first ligand and 1,10-phenanthro- line or 2,2＇-dipyridyl as the second ligand. The ternary Eu（ Ⅲ ） complexes were characterized by elemental analysis, IR and TG-DTG methods. In these complexes, the Eu （Ⅲ） ions are bonded to the oxygen atoms of carboxylate and the nitrogen atoms of neutral ligands. Four complexes whose second ligand is 1,10- phenanthrolin have fine thermal stability. Excitation and luminescence spectra of the tide complexes reveal that the fluorescence of the complexes in which 1,10- phenanthrolin as the second ligand are more intensive than those complexes in which 2, 2＇-dipyridyl as the second ligand. The order of the strongest emission peak of seven ternary complexes is： Eu（β-PPA）3phen 〉 Eu（BA）3phen 〉 Eu（PLA）3phen 〉 Eu（BA）3bipy 〉 Eu （ PEA）3bipy 〉 Eu （ CA ）3phen · H2O 〉 Eu （ CA ）3bipy （BA ： benzoic ; PEA ： phenylacetic ; β-PPA ：

Synthesis and photoluminescent performance of novel europium(Ⅲ) carboxylates with heterocyclic ancillary ligands

Five novel europium(Ⅲ)complexes with 2-[4-(dibutylamino)-2-hydroxybenzoyl]benzoic acid(DAHB)as primary ligand and bathophenanthroline(batho),2,2’-bipyridyl(bipy),5,6-dimethyl-1,10-phenanthroline(dmph),1,10-phenanthroline(phen)as ancillary ligands were syn-thesized via solution precipitation method.The structural formulae of synthesized complexes were speculated to be Eu(DABH)_(3)·2H_(2)O(C1),Eu(DABH)_(3)·batho(C2),Eu(DABH)_(3)·bipy(C3),Eu(DABH)_(3)·dmph(C4)and Eu(DABH)_(3)·phen(C5)by elemental analysis,infrared spectroscopy and proton nuclear magnetic resonance spec-troscopy(^(1)H-NMR).The photoluminescent properties and thermal stability of the complexes were investigated by photoluminescent spectroscopy and thermogravimetric analysis(TG-DTG),respectively.The Commission Inter-nationale de I’Eclairage(CIE)color coordinates,Judd–Ofelt intensity parameter(Ω_(2)),total quantum yield,intrinsic quantum efficiency and energy transfer dynamics of com-plexes were also explored.The excitation spectra of com-plexes are extended up to visible region.These complexes exhibit characteristic photoemission of Eu^(3+)metal ion with high color purity in red region attributed to efficient energy transfer from ligand to metal ion.The replacement of water molecules from coordination sphere of europium ion by ancillary ligands results in enhancement of luminescent properties of the C2–C5 complexes,indicating that ancillary ligands act as additional light harvesting centers in sensiti-zation phenomenon.The thermal studies show that these complexes are suitable for meeting the requirement of temperature for fabrication of OLEDs devices.

Selective adsorption behaviors of guest molecules COR in the hexamer host networks at liquid/solid interface

Here,the selective adsorption behaviors of guest molecule COR in two hexamer host grids were investigated by means of scanning tunnelling microscope(STM).The assembled structures of small functional organic molecules TTBTA and TATBA were thermodynamically stable.Interestingly,the introduction of the guest molecule COR destroyed the original hexamer structure of TTBTA and combined with it to form a new triangular host-guest system.Different from TTBTA,the introduction of the guest molecule COR did not affect the six-membered ring structure of TATBA.Furthermore,the co-assembly structure of TTBTA/TATBA/COR was established and the guest molecule COR showed preferential adsorption to the TATBA host grid.Density functional theory(DFT)calculations had been performed to disclose the mechanism of the involved assemblies.

Functionalized Metal-organic Frameworks for White Light Emission and Highly Sensitive Sensing of PA and Fe^(3+)/Al^(3+)

Three isomorphic Ln-MOFs[Ln(bcbob)(H_(2)O)(DMF)](Ln=Tb for 1,Eu for 2,Gd for 3;DMF=N,N-dimethylformamide)have been constructed from a semi-rigid V-shaped organic linker 3,5-bis((4'-carboxyl-benzyl)oxy)benzoilate acid(H3bcbob)under solvothermal conditions.X-ray single-crystal diffraction analysis re-veals that they exhibit a two-dimensional(2D)layered structure.Compounds 1~3 show the characteristic green and red emissions of Ln^(3+)and blue emission arising from the organic ligand,respectively.Based on their photo-luminescence properties,the white-light emitting materials 4 and 5 with longer fluorescence lifetime(ms grade)and higher quantum yield(e.g.40.61%for 4)are fabricated.Remarkably,1 exhibits good sensing ability on ni-troaromatic compounds,especially for picric acid(PA).In addition,1 is still a highly selective sensing material for Fe^(3+)and Al^(3+).