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102. Competitive Adsorption of NH3and H2O in Metal–Organic Framework Materials: MOF-74

Author

Tan, Kui, Ullah, Saif, Pandey, Haardik, Cedeño-Morales, Eder M., Wang, Hao, Wang, Kunyu, Zhou, Hong-Cai, Li, Jing, and Thonhauser, Timo

Abstract

Elucidating the interaction between coadsorbed H2O and NH3in metal–organic frameworks (MOFs) is of paramount importance to uncover mechanistic details of their competitive coadsorption behavior as well as to guide the design of new materials for enhanced NH3adsorption in humid environments. Nevertheless, molecular competition between NH3and H2O within the confined nanopores of MOFs was rarely explored and is poorly understood due to challenges in characterization. Here, we combine in situ infrared spectroscopy with ab initio calculations to unveil the competition of NH3and H2O for occupying active adsorption sites in the representative MOF-74 material by analyzing the kinetics and energetics of the molecular exchange process. We find that at a high NH3/H2O ratio, the incoming NH3is capable of displacing metal-bound H2O and moving it to secondary adsorption sites due to the stronger binding of NH3compared with H2O. Interestingly, the reverse process of H2O displacing metal-bound NH3is also possible upon increasing water concentration. Our calculations show that H2O exchanging the preabsorbed NH3at the metal site is driven not only by a reduced kinetic barrier but also by a favorable energetical state resulting from the formation of water clusters at metal sites and intermolecular H-bonding between the metal-coordinated H2O and displaced NH3. Our finding emphasizes that the description of molecular occupation in MOFs at equilibrium cannot simply be established by comparing molecules’ binding energies at their strongest binding sites derived by single-component measurements; rather, intermolecular interactions can greatly affect molecular distribution at equilibrium. Furthermore, we show that vibrational modes of adsorbed NH3are markedly perturbed upon contact with water molecules, accompanied by a large frequency shift (>30 cm–1) and considerable intensity decrease, which arises from the freezing of NH3vibrations by coadsorbed H2O. The mechanistic insight obtained through our study sheds light on molecular coadsorption processes in MOFs and helps to assess NH3removal efficiency of MOFs containing open-metal sites under realistic conditions, particularly in the presence of humidity.

Published
2022
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112. Progesterone receptor membrane component 1 is involved in oral cancer cell metastasis

Author

Huang, Hsun‐Yu, primary, Chou, Hsiu‐Chuan, additional, Law, Ching‐Hsuan, additional, Chang, Wan‐Ting, additional, Wen, Tzu‐Ning, additional, Liao, En‐Chi, additional, Lin, Meng‐Wei, additional, Lin, Li‐Hsun, additional, Wei, Yu‐Shan, additional, Tsai, Yi‐Ting, additional, Chen, Hsin‐Yi, additional, Tan, Kui‐Thong, additional, Kuo, Wen‐Hung, additional, Ko, Mei‐Lan, additional, Chang, Shing‐Jyh, additional, Lee, Ying‐Ray, additional, and Chan, Hong‐Lin, additional

Published
2020
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116. A Beehive Inspired Hydrogen Photocatalytic Device Integrating a Carbo‐Benzene Triptych Material for Efficient Solar Photo‐Reduction of Seawater

Author

Cure, Jérémy, primary, Cocq, Kévin, additional, Nicollet, Andréa, additional, Tan, Kui, additional, Hungria, Teresa, additional, Assie‐Souleille, Sandrine, additional, Vivies, Séverine, additional, Salvagnac, Ludovic, additional, Quevedo‐Lopez, Manuel, additional, Maraval, Valérie, additional, Chauvin, Remi, additional, Estève, Alain, additional, and Rossi, Carole, additional

Published
2020
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122. Fluorescence “Turn-on” Lectin Sensors Fabricated by Ligand-Assisted Labeling Probes for Detecting Protein–Glycoprotein Interactions

Author

Li, Pei-Jhen, primary, Anwar, Mohammad Tarigue, additional, Fan, Chen-Yo, additional, Juang, Duane S., additional, Lin, Hsin-Yi, additional, Chang, Tsung-Che, additional, Kawade, Sachin Kisan, additional, Chen, Hsiang-Jung, additional, Chen, Yu-Ju, additional, Tan, Kui-Thong, additional, and Lin, Chun-Cheng, additional

Published
2019
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123. Publisher Correction: Rapid desolvation-triggered domino lattice rearrangement in a metal–organic framework

Author

Lo, Sheng-Han, primary, Feng, Liang, additional, Tan, Kui, additional, Huang, Zhehao, additional, Yuan, Shuai, additional, Wang, Kun-Yu, additional, Li, Bing-Han, additional, Liu, Wan-Ling, additional, Day, Gregory S., additional, Tao, Songsheng, additional, Yang, Chun-Chuen, additional, Luo, Tzuoo-Tsair, additional, Lin, Chia-Her, additional, Wang, Sue-Lein, additional, Billinge, Simon J. L., additional, Lu, Kuang-Lieh, additional, Chabal, Yves J., additional, Zou, Xiaodong, additional, and Zhou, Hong-Cai, additional

Published
2019
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124. Rapid desolvation-triggered domino lattice rearrangement in a metal–organic framework

Author

Lo, Sheng-Han, primary, Feng, Liang, additional, Tan, Kui, additional, Huang, Zhehao, additional, Yuan, Shuai, additional, Wang, Kun-Yu, additional, Li, Bing-Han, additional, Liu, Wan-Ling, additional, Day, Gregory S., additional, Tao, Songsheng, additional, Yang, Chun-Chuen, additional, Luo, Tzuoo-Tsair, additional, Lin, Chia-Her, additional, Wang, Sue-Lein, additional, Billinge, Simon J. L., additional, Lu, Kuang-Lieh, additional, Chabal, Yves J., additional, Zou, Xiaodong, additional, and Zhou, Hong-Cai, additional

Published
2019
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125. Target-activated streptavidin–biotin controlled binding probe† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c7sc04014h

Author

Wu, Yung-Peng, Chew, Chee Ying, Li, Tian-Neng, Chung, Tzu-Hsuan, Chang, En-Hao, Lam, Chak Hin, and Tan, Kui-Thong

Subjects
Chemistry
Abstract

The streptavidin–biotin controlled binding probe has several advantages for the detection of enzymes and reactive small molecules, such as minimal background, multiple signal amplification steps, and wide selection of the optimal dyes for detection., Target-activated chemical probes are important tools in basic biological research and medical diagnosis for monitoring enzyme activities and reactive small molecules. Based on the fluorescence turn-on mechanism, they can be divided into two classes: dye-based fluorescent probes and caged-luciferin. In this paper, we introduce a new type of chemical probe in which the fluorescence turn-on is based on controlled streptavidin–biotin binding. Compared to conventional probes, the streptavidin–biotin controlled binding probe has several advantages, such as minimal background at its “OFF” state, multiple signal amplification steps, and unlimited selection of the optimal dyes for detection. To expand the scope, a new synthetic method was developed, through which a wider range of analyte recognition groups can be easily introduced to construct the binding probe. This probe design was successfully applied to image and study secreted peroxynitrite (ONOO–) at the cell surface of macrophages where information on ONOO– is difficult to obtain. As the signals are generated upon the binding of streptavidin to the biotin probe, this highly versatile design can not only be used in fluorescence detection but can also be applied in various other detection modes, such as electrochemical and enzyme-amplified luminescence detection.

Published
2017

126. Regioselective or Asymmetric 1,2-Addition to Aldehydes

Author

Tan, Kui-Thong, primary, Chng, Shu-Sin, additional, Cheng, Hin-Soon, additional, Loh, Teck-Peng, additional, Rudolph, Jens, additional, Bolm, Carsten, additional, Lombardo, Marco, additional, Licciulli, Sebastiano, additional, Morganti, Stefano, additional, and Trombini, Claudio, additional

Published
2005
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129. Modulation of water vapor sorption by a 4th generation metal-organic material with a rigid framework and self-switching pores

Author

Zhang, Shi-Yuan, Jensen, Stephanie, Tan, Kui, Wojtas, Lukasz, Roveto, Matthew, Cure, Jeremy, Thonhauser, Timo, Chabal, Yves J., Zaworotko, Michael J., SFI, and Department of Energy, Basic Energy Sciences, Division of Materials Sciences and Engineering

Subjects
water vapor, stable adsorbents
Abstract

peer-reviewed Hydrolytically stable adsorbents are needed for water vapor sorption related applications; however, design principles for porous materials with tunable water sorption behavior are not yet established. Here, we report that a platform of fourth-generation metal–organic materials (MOMs) with rigid frameworks and self-switching pores can adapt their pores to modulate water sorption. This platform is based upon the hydrolytically stable material CMOM-3S, which exhibits bnn topology and is composed of rod building blocks based upon S-mandelate ligands, 4,4-bipyridine ligands, and extraframework triflate anions. Isostructural variants of CMOM-3S were prepared using substituted R-mandelate ligands and exhibit diverse water vapor uptakes (20–67 cm3/g) and pore filling pressures (P/P0, 0.55–0.75). [Co2(R-4-Cl-man)2(bpy)3](OTf) (33R) is of particular interest because of its unusual isotherm. Insight into the different water sorption properties of the materials studied was gained from analysis of in situ vibrational spectra, which indicate self-switching pores via perturbation of extraframework triflate anions and mandelate linker ligands to generate distinctive water binding sites. Water vapor adsorption was studied using in situ differential spectra that reveal gradual singlet water occupancy followed by aggregation of water clusters in the channels upon increasing pressure. First-principles calculations identified the water binding sites and provide structural insight on how adsorbed water molecules affect the structures and the binding sites. Stronger triflate hydrogen bonding to the framework along with significant charge redistribution were determined for water binding in 33R. This study provides insight into a new class of fourth-generation (self-switching pores) MOM and the resulting effect upon water vapor sorption properties

Published
2018

130. Engineering Structural Dynamics of Zirconium Metal–Organic Frameworks Based on Natural C4 Linkers

Author

Wang, Sujing, primary, Xhaferaj, Nertil, additional, Wahiduzzaman, Mohammad, additional, Oyekan, Kolade, additional, Li, Xiao, additional, Wei, Kevin, additional, Zheng, Bin, additional, Tissot, Antoine, additional, Marrot, Jérôme, additional, Shepard, William, additional, Martineau-Corcos, Charlotte, additional, Filinchuk, Yaroslav, additional, Tan, Kui, additional, Maurin, Guillaume, additional, and Serre, Christian, additional

Published
2019
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135. Stable and Active Oxidation Catalysis by Cooperative Lattice Oxygen Redox on SmMn2O5 Mullite Surface

Author

Zheng, Yongping, primary, Thampy, Sampreetha, additional, Ashburn, Nickolas, additional, Dillon, Sean, additional, Wang, Luhua, additional, Jangjou, Yasser, additional, Tan, Kui, additional, Kong, Fantai, additional, Nie, Yifan, additional, Kim, Moon J., additional, Epling, William S., additional, Chabal, Yves J., additional, Hsu, Julia W. P., additional, and Cho, Kyeongjae, additional

Published
2019
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136. Reactivity of Atomic Layer Deposition Precursors with OH/H2O-Containing Metal Organic Framework Materials

Author

Tan, Kui, primary, Jensen, Stephanie, additional, Feng, Liang, additional, Wang, Hao, additional, Yuan, Shuai, additional, Ferreri, Melanie, additional, Klesko, Joseph P., additional, Rahman, Rezwanur, additional, Cure, Jeremy, additional, Li, Jing, additional, Zhou, Hong-Cai, additional, Thonhauser, Timo, additional, and Chabal, Yves J., additional

Published
2019
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138. High stability of ultra-small and isolated gold nanoparticles in metal–organic framework materials

Author

Cure, Jérémy, primary, Mattson, Eric, additional, Cocq, Kévin, additional, Assi, Hala, additional, Jensen, Stephanie, additional, Tan, Kui, additional, Catalano, Massimo, additional, Yuan, Shuai, additional, Wang, Hao, additional, Feng, Liang, additional, Zhang, Peng, additional, Kwon, Sunah, additional, Veyan, Jean-François, additional, Cabrera, Yasiel, additional, Zhang, Guoyu, additional, Li, Jing, additional, Kim, Moon, additional, Zhou, Hong-Cai, additional, Chabal, Yves J., additional, and Thonhauser, Timo, additional

Published
2019
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139. Metal–Organic Framework Based Hydrogen-Bonding Nanotrap for Efficient Acetylene Storage and Separation

Author

Ye, Yingxiang, Xian, Shikai, Cui, Hui, Tan, Kui, Gong, Lingshan, Liang, Bin, Pham, Tony, Pandey, Haardik, Krishna, Rajamani, Lan, Pui Ching, Forrest, Katherine A., Space, Brian, Thonhauser, Timo, Li, Jing, and Ma, Shengqian

Abstract

The removal of carbon dioxide (CO2) from acetylene (C2H2) is a critical industrial process for manufacturing high-purity C2H2. However, it remains challenging to address the tradeoff between adsorption capacity and selectivity, on account of their similar physical properties and molecular sizes. To overcome this difficulty, here we report a novel strategy involving the regulation of a hydrogen-bonding nanotrap on the pore surface to promote the separation of C2H2/CO2mixtures in three isostructural metal–organic frameworks (MOFs, named MIL-160, CAU-10H, and CAU-23, respectively). Among them, MIL-160, which has abundant hydrogen-bonding acceptors as nanotraps, can selectively capture acetylene molecules and demonstrates an ultrahigh C2H2storage capacity (191 cm3g–1, or 213 cm3cm–3) but much less CO2uptake (90 cm3g–1) under ambient conditions. The C2H2adsorption amount of MIL-160 is remarkably higher than those for the other two isostructural MOFs (86 and 119 cm3g–1for CAU-10H and CAU-23, respectively) under the same conditions. More importantly, both simulation and experimental breakthrough results show that MIL-160 sets a new benchmark for equimolar C2H2/CO2separation in terms of the separation potential (Δqbreak= 5.02 mol/kg) and C2H2productivity (6.8 mol/kg). In addition, in situFT-IR experiments and computational modeling further reveal that the unique host–guest multiple hydrogen-bonding interaction between the nanotrap and C2H2is the key factor for achieving the extraordinary acetylene storage capacity and superior C2H2/CO2selectivity. This work provides a novel and powerful approach to address the tradeoff of this extremely challenging gas separation.

Published
2022
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140. Simultaneous Trapping of C 2 H 2 and C 2 H 6 from a Ternary Mixture of C 2 H 2 /C 2 H 4 /C 2 H 6 in a Robust Metal–Organic Framework for the Purification of C 2 H 4

Author

Hao, Hong‐Guo, primary, Zhao, Yun‐Feng, additional, Chen, Di‐Ming, additional, Yu, Jia‐Mei, additional, Tan, Kui, additional, Ma, Shengqian, additional, Chabal, Yves, additional, Zhang, Zhi‐Ming, additional, Dou, Jian‐Min, additional, Xiao, Zi‐Hui, additional, Day, Gregory, additional, Zhou, Hong‐Cai, additional, and Lu, Tong‐Bu, additional

Published
2018
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141. Protein sensing in living cells by molecular rotor-based fluorescence-switchable chemical probes† †Electronic supplementary information (ESI) available: See DOI: 10.1039/c5sc02808f Click here for additional data file

Author

Yu, Wan-Ting, Wu, Ting-Wei, Huang, Chi-Ling, Chen, I-Chia, and Tan, Kui-Thong

Subjects
Chemistry
Abstract

We introduce a general design to construct fluorescence-switching probes. Upon the interaction of the ligand with the protein, the crowded surroundings restrict the bond rotation of the fluorescent molecular rotor to trigger a strong fluorescence signal, which is reduced upon the addition of a competitive ligand or after protein degradation., In this paper, we introduce a general design to construct fluorescence-switching probes by using conjugates of a fluorescent molecular rotor and protein specific ligands for the selective protein detection and real-time tracking of protein degradation in living cells. Upon the interaction of the ligand with the protein ligand-binding domain, the crowded surroundings restrict the bond rotation of the fluorescent molecular rotor to trigger the emission of a strong fluorescence signal, which is reduced upon the addition of a competitive ligand or after protein degradation. With this probe design, two fluorescent probes for MGMT and hCAII proteins were constructed and applied for detecting the endogenous proteins in living cells. In addition, real-time degradation kinetics of the alkylated-MGMT at the single living cell level were revealed for the first time. We believe that this fluorescence-switching probe design can possibly be extended for the analysis of other proteins, for which there are still no effective tools to visualize them in living cells.

Published
2015

142. Near-infrared fluorescence activation probes based on disassembly-induced emission cyanine dye† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c5sc01330e Click here for additional data file

Author

Hou, Tai-Cheng, Wu, Ying-Yi, Chiang, Po-Yi, and Tan, Kui-Thong

Subjects
Chemistry, genetic structures
Abstract

In the presence of target analyte, bright fluorescence in the near-IR region is emitted through the recognition-induced disassembly of the probe aggregate., Currently most of the fluorogenic probes are designed for the detection of enzymes which work by converting the non-fluorescence substrate into the fluorescence product via an enzymatic reaction. On the other hand, the design of fluorogenic probes for non-enzymatic proteins remains a great challenge. Herein, we report a general strategy to create near-IR fluorogenic probes, where a small molecule ligand is conjugated to a novel γ-phenyl-substituted Cy5 fluorophore, for the selective detection of proteins through a non-enzymatic process. Detail mechanistic studies reveal that the probes self-assemble to form fluorescence-quenched J-type aggregate. In the presence of target analyte, bright fluorescence in the near-IR region is emitted through the recognition-induced disassembly of the probe aggregate. This Cy5 fluorophore is a unique self-assembly/disassembly dye as it gives remarkable fluorescence enhancement. Based on the same design, three different fluorogenic probes were constructed and one of them was applied for the no-wash imaging of tumor cells for the detection of hypoxia-induced cancer-specific biomarker, transmembrane-type carbonic anhydrase IX.

Published
2015

143. Improved Stabilities of Labeling Probes for the Selective Modification of Endogenous Proteins in Living Cells and In Vivo.

Author

Lin, Kuan‐Yu, Hin Lam, Chak, Lin, Xin‐Hui, Hsu, Jung‐I, Fan, Syuan‐Yun, Gupta, Nitesh K., Lin, Yu‐Chun, Khoon Tee, Boon, Li, Jui‐Ping, Chen, Jen‐Kun, and Tan, Kui‐Thong

Subjects
PROTEINS, MEMBRANE proteins
Abstract

To date, various affinity‐based protein labeling probes have been developed and applied in biological research to modify endogenous proteins in cell lysates and on the cell surface. However, the reactive groups on the labeling probes are also the cause of probe instability and nonselective labeling in a more complex environment, e. g. intracellular and in vivo. Here, we show that labeling probes composed of a sterically stabilized difluorophenyl pivalate can achieve efficient and selective labeling of endogenous proteins on the cell surface, inside living cells and in vivo. As compared with the existing protein labeling probes, probes with the difluorophenyl pivalate exhibit several advantages, including long‐term stability in stock solutions, resistance to enzymatic hydrolysis and can be customized easily with diverse fluorophores and protein ligands. With this probe design, endogenous hypoxia biomarker in living cells and nude mice were successfully labeled and validated by in vivo, ex vivo, and immunohistochemistry imaging. [ABSTRACT FROM AUTHOR]

Published
2021
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144. Flexible Zn-MOF with Rare Underlying scuTopology for Effective Separation of C6 Alkane Isomers

Author

Velasco, Ever, Xian, Shikai, Wang, Hao, Teat, Simon J., Olson, David H., Tan, Kui, Ullah, Saif, Osborn Popp, Thomas M., Bernstein, Ashley D., Oyekan, Kolade A, Nieuwkoop, Andrew J., Thonhauser, Timo, and Li, Jing

Abstract

Adsorptive separation by porous solids provides an energy-efficient alternative for the purification of important chemical species compared to energy-intensive distillations. Particularly, the separation of linear hexane isomers from its branched counterparts is crucial to produce premium grade gasoline with high research octane number (RON). Herein, we report the synthesis of a new, flexible zinc-based metal–organic framework, [Zn5(μ3-OH)2(adtb)2(H2O)5·5 DMA] (Zn-adtb), constructed from a butterfly shaped carboxylate linker with underlying (4,8)-connected scutopology capable of separating the C6 isomers nHEX, 3MP, and 23DMB. The sorbate–sorbent interactions and separation mechanisms were investigated and analyzed through in situ FTIR, solid state NMR measurements and computational modeling. These studies reveal that Zn-adtb discriminates the nHEX/3MP isomer pair through a kinetic separation mechanism and the nHEX/23DMB isomer pair through a molecular sieving mechanism. Column breakthrough measurements further demonstrate the efficient separation of linear nHEX from the mono- and dibranched isomers.

Published
2021
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145. Affinity‐switchable biotin probes for the analysis of enzymes and small reactive molecules on microarray platform.

Author

Wu, Chia‐Lin, Fan, Chen‐Yo, Lin, Chun‐Cheng, and Tan, Kui‐Thong

Subjects
SMALL molecules, BIOTIN, ENZYMES, THERAPEUTIC immobilization, ALKALINE phosphatase, PSEUDOPOTENTIAL method
Abstract

Array‐based analytical platforms have a distinct advantage of being able to detect analytes rapidly and simultaneously with the use of very small quantities of reagents and samples. However, the analyses of enzyme activities using this technique remain challenging, as the heterogeneous interface between the enzyme in the solution and the probe on the array surface impede the efficient binding and the subsequent enzymatic reaction. In this paper, we showed that the combination of affinity‐switchable biotin (ASB) probes and a novel click‐chemistry based immobilization method can overcome this heterogeneity problem. Three ASB probes were synthesized for the detection of alkaline phosphatase, nitroreductase, and the fluoride ion. This approach can be applied to determine the relative levels of phosphatase in different cell lines. We believe that the new strategy holds great potential for the effective sensing of a wide range of biomolecules in the future. [ABSTRACT FROM AUTHOR]

Published
2021
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146. Breakpoint mapping of a t(9;22;12) chronic myeloid leukaemia patient with e14a3 BCR‐ABL1 transcript using Nanopore sequencing.

Author

Zhao, Hu, Chen, Yuan, Shen, Chanjuan, Li, Lingshu, Li, Qingzhao, Tan, Kui, Huang, Huang, and Hu, Guoyu

Abstract

Background: The genetic changes in chronic myeloid leukaemia (CML) have been well established, although challenges persist in cases with rare fusion transcripts or complex variant translocations. Here, we present a CML patient with e14a3 BCR‐ABL1 transcript and t(9;22;12) variant Philadelphia (Ph) chromosome. Methods: Cytogenetic analysis and fluorescence in situ hybridization (FISH) was performed to identify the chromosomal aberrations and gene fusions. Rare fusion transcript was verified by a reverse transcription‐polymerase chain reaction (RT‐PCR). Breakpoints were characterized and validated using Oxford Nanopore Technologies (ONT) (Oxford, UK) and Sanger sequencing, respectively. Results: The karyotype showed the translocation t(9;22;12)(q34;q11.2;q24) [20] and FISH indicated 40% positive BCR‐ABL1 fusion signals. The RT‐PCR suggested e14a3 type fusion transcript. The ONT sequencing analysis identified specific positions of translocation breakpoints: chr22:23633040–chr9:133729579, chr12:121567595–chr22:24701405, which were confirmed using Sanger sequencing. The patient achieved molecular remission 3 months after imatinib therapy. Conclusions: The present study indicates Nanopore sequencing as a valid strategy, which can characterize breakpoints precisely in special clinical cases with atypical structural variations. CML patients with e14a3 transcripts may have good clinical course in the tyrosine kinase inhibitor era, as reviewed here. [ABSTRACT FROM AUTHOR]

Published
2021
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147. Rapid and Selective Labeling of Endogenous Transmembrane Proteins in Living Cells with a Difluorophenyl Ester Affinity‐Based Probe.

Author

Chan, Hsin‐Ju, Lin, Xin‐Hui, Fan, Syuan‐Yun, Ru Hwu, Jih, and Tan, Kui‐Thong

Subjects
MEMBRANE proteins, CELL imaging, FLUORIMETRY, ESTERS, DISTRIBUTION (Probability theory), DRUG labeling, ELECTROPHILES, LABELS
Abstract

The long‐term stability of affinity‐based protein labeling probes is crucial to obtain reproducible protein labeling results. However, highly stable probes generally suffer from low protein labeling efficiency and pose significant challenges when labeling low abundance native proteins in living cells. In this paper, we report that protein labeling probes based on an ortho‐difluorophenyl ester reactive module exhibit long‐term stability in DMSO stock solution and aqueous buffer, yet they can undergo rapid and selective labeling of native proteins. This novel electrophile can be customized with a wide range of different protein ligands and is particularly well‐suited for the labeling and imaging of transmembrane proteins. With this probe design, the identity and relative levels of basal and hypoxia‐induced transmembrane carbonic anhydrases were revealed by live cell imaging and in‐gel fluorescence analysis. We believe that the extension of this difluorophenyl ester reactive module would allow for the specific labeling of various endogenous membrane proteins, facilitating in‐depth studies of their distribution and functions in biological processes. [ABSTRACT FROM AUTHOR]

Published
2020
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148. Robust fluorescent calcium coordination polymers as Cu2+ sensors with high sensitivity and fast response.

Author

Wu, Zhao-Feng, Velasco, Ever, Shan, Chuan, Tan, Kui, Zhang, Zhi-Zhuan, Hu, Qian-Qian, Xing, Kai, Huang, Xiao-Ying, and Li, Jing

Abstract

A three-dimensional (3D) and highly fluorescent calcium-based coordination polymer (Ca-CP) has been synthesized and structurally characterized. Built on a strongly fluorescent (FL) chromophore ligand, [Ca(H2tcbpe)(H2O)2] (1) (H4tcbpe = 4′,4′′′,4′′′′′,4′′′′′′′-(ethene-1,1,2,2-tetrayl)tetrakis(([1,1′-biphenyl]-4-carboxylic acid))) is highly luminescent. Photoluminescence (PL) studies indicate that 1 undergoes a bathochromic shift in emission energy from blue to green color upon outgassing or under mechanic force. Notably, 1 exhibits selective FL sensing for Cu2+ ions with a detection limit (LOD) of 0.064 ppm, far below the U.S. WHO and EPA standard for drinking water. Detailed investigation of the sensing mechanism reveals that uncoordinated COO− groups in 1 play a major role in recognizing Cu2+ ions. This is supported through analysis by multiple characterization methods including IR, EDS and XPS. Based on the proposed mechanism, an isostructural [Ca(H2tcbpe-F)(H2O)2] Ca-CP (2) (H4tcbpe-F = 4′,4′′′,4′′′′′,4′′′′′′′-(ethene-1,1,2,2-tetrayl)tetrakis(3-fluoro-[1,1′-biphenyl]-4-carboxylic acid)) is synthesized and tested. Compound 2 demonstrates a ten-fold enhancement in Cu2+ detection sensitivity with a ppb level detection limit. The strong enhancement in the detection sensitivity results from optimized electron density around free COO− groups by introducing electron withdrawing F groups onto the backbone of the organic linker. Excellent chemical stability under a wide range of pH conditions (1–14), high sensitivity and rapid fluorescence quenching response time (seconds) make these compounds ideal candidates for use as Cu2+ sensors. [ABSTRACT FROM AUTHOR]

Published
2020
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