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Fabrication Of Photoresponsive Crystalline Artificial Muscles Based On Pegylated Covalent Organic Framework Membranes, Xiuxiu Guo, Tianhui Mao, Zhifang Wang, Peng Cheng, Yao Chen, Shengqian Ma, Zhenjie Zhang

Chemistry Faculty Publications

Seeking new photoresponsive materials with high energy conversion efficiency, good mechanical properties, as well as well-defined photoactuation mechanisms is of paramount significance. To address these challenges, we first introduced crystalline covalent organic frameworks (COFs) into the photoactuator field and created a facile fabrication strategy to directly install photoresponsive functional groups (i.e., acylhydrazone) on the skeletons of COFs. Herein, an approach to use polyethylene glycol (PEG) cross-linked dimers as the building blocks of the COF-42 platform was developed and afforded a series of uniform and freestanding membranes (PEG-COF-42) with outstanding mechanical properties (e.g., high flexibility and mechanical strength). Notably, these membranes …

The Activity Of Sulfono-Γ-Aapeptide Helical Foldamers That Mimic Glp-1, Peng Sang, Zhihong Zhou, Yan Shi, Candy Lee, Zaid Amso, David Huang, Timothy Odom, Vân T.B. Nguyen-Tran, Weijun Shen, Jianfeng Cai

Chemistry Faculty Publications

Existing long α-helix mimicking necessitates the retention of most natural amino acid residues to maintain their biological activity. Here, we report the exploration of helical sulfono-γ-AApeptides with entire unnatural backbones for their ability to structurally and functionally mimic glucagon-like peptide 1 (GLP-1). Our findings suggest that efficient construction of novel GLP-1 receptor (GLP-1R) agonists could be achieved with nanomolar potencies. In addition, the resulting sulfono-γ-AApeptides were also proved to display remarkable stability against enzymatic degradation compared to GLP-1, augmenting their biological potential. This alternative strategy of α-helix mimicking, as a proof of concept, could provide a new paradigm to prepare …

The Folding Propensity Of Α/Sulfono-Γ-Aa Peptidic Foldamers With Both Left- And Right-Handedness, Peng Teng, Mengmeng Zheng, Darrell Cerrato, Yan Shi, Mi Zhou, Songyi Xue, Wei Jiang, Lukasz Wojtas, Li-June Ming, Yong Hu, Jianfeng Cai

Chemistry Faculty Publications

The discovery and application of new types of helical peptidic foldamers have been an attractive endeavor to enable the development of new materials, catalysts and biological molecules. To maximize their application potential through structure-based design, it is imperative to control their helical handedness based on their molecular scaffold. Herein we first demonstrate the generalizability of the solid-state right-handed helical propensity of the 413-helix of L-α/L-sulfono-γ-AA peptides that as short as 11-mer, using the high-resolution X-ray single crystallography. The atomic level folding conformation of the foldamers was also elucidated by 2D NMR and circular dichroism under various conditions. Subsequently, we show …

Beyond Confined Catalysis In Porous Materials, Xiaoliang Wang, Pui Ching Lan, Sai Wang, Shengqian Ma

Chemistry Faculty Publications

No abstract provided.

C‑Jun And Foxo1 Mediate The Expression Of Oncogenic Pkc‑Ι In Human Prostate Cancer Cells With An Interplay Between Nf‑Κb, Il‑8 And Icam‑1, Wishrawana S. Ratnayake, Christopher A. Apostolatos, Sloan Breedy, Mildred Acevedo-Duncan

Chemistry Faculty Publications

Aggressive and metastatic prostate cancers are among the leading causes of fatality in men. Prior observations by the authors regarding atypical protein kinase C isoforms (aPKCs) in relation to prostate cancers demonstrated elevated levels of PKC‑iota (PKC‑ι) in patient samples compared to non‑malignant prostate tissues. This indicates that PKC‑ι is a potential biomarker for initiating and maintaining prostate carcinogenesis. In addition, PKC‑ι is an oncogene that encourages the activation of the nuclear factor (NF)‑κB, assisting carcinogenesis. The specific inhibition of PKC‑ι de‑regulated the expression of both PKC‑ι and its phosphorylation; thus, PKC‑ι functionally controls its own expression in prostate carcinoma. …

Tanshinone Iia Inhibits Epithelial-To-Mesenchymal Transition Through Regulating Β-Arrestin1 Mediated Β-Catenin Signaling Pathway In Colorectal Cancer, Qing Song, Liu Yang, Zhifen Han, Xinnan Wu, Ruixiao Li, Lihong Zhou, Ningning Liu, Hua Sui, Jianfeng Cai, Yan Wang, Qing Ji, Qi Li

Chemistry Faculty Publications

Background: Tanshinone IIA (Tan IIA) is a major active ingredient extracted from Salvia miltiorrhiza, which has been proved to inhibit metastasis of various cancers including colorectal cancer (CRC). However, the detailed mechanisms of Tan IIA against CRC metastasis are not well explored. Epithelial-to-mesenchymal transition (EMT) exerts an important regulatory role in CRC metastasis, and our previous mechanism studies demonstrated that β-arrestin1 could regulate CRC EMT partly through β-catenin signaling pathway. Therefore, in this work we investigated whether Tan IIA could regulate CRC EMT through β-arrestin1-mediated β-catenin signaling pathway in vivo and in vitro.

Methods: The nude mice tail vein …

Highly Efficient Electrocatalytic Hydrogen Evolution Promoted By O–Mo–C Interfaces Of Ultrafine Β-Mo2C Nanostructures, Hui Yang, Xing Chen, Guoxiang Hu, Wan-Ting Chen, Siobhan J. Bradley, Weijie Zhang, Gaurav Verma, Thomas Nann, De-En Jiang, Paul E. Kruger, Xiangke Wang, He Tian, Geoffrey I. N. Waterhouse, Shane G. Telfer, Shengqian Ma

Chemistry Faculty Publications

Optimizing interfacial contacts and thus electron transfer phenomena in heterogeneous electrocatalysts is an effective approach for enhancing electrocatalytic performance. Herein, we successfully synthesized ultrafine β-Mo2C nanoparticles confined within hollow capsules of nitrogen-doped porous carbon (β-Mo2C@NPCC) and found that the surface layer of molybdenum atoms was further oxidized to a single Mo–O surface layer, thus producing intimate O–Mo–C interfaces. An arsenal of complementary technologies, including XPS, atomic-resolution HAADF-STEM, and XAS analysis clearly reveals the existence of O–Mo–C interfaces for these surface-engineered ultrafine nanostructures. The β-Mo2C@NPCC electrocatalyst exhibited excellent electrocatalytic activity for the hydrogen evolution reaction (HER) in water. Theoretical studies indicate …

Synthesis, Characterization, And Investigation Of The Antimicrobial Activity Of Cetylpyridinium Tetrachlorozincate, Viktor Dubovoy, Shiri Nawrocki, Gaurav Verma, Lukasz Wojtas, Primit Desai, Hassan Al-Tameemi, Tatiana V. Brinzari, Michael Stranick, Dailin Chen, Shaopeng Xu, Shengqian Ma, Jeffrey M. Boyd, Tewodros Asefa, Long Pan

Chemistry Faculty Publications

Cetylpyridinium tetrachlorozincate (referred to herein as (CP)₂ZnCl₄) was synthesized and its solid-state structure was elucidated via single-crystal X-ray diffraction (SC-XRD), revealing a stoichiometry of C₄₂H₇₆Cl₄N₂Zn with two cetylpyridinium (CP) cations per [ZnCl₄]^2– tetrahedra. Crystal structures at 100 and 298 K exhibited a zig-zag pattern with alternating alkyl chains and zinc units. The material showed potential for application as a broad-spectrum antimicrobial agent, to reduce volatile sulfur compounds (VSCs) generated by bacteria, and in the fabrication of advanced functional materials. Minimum inhibitory concentration (MIC) of (CP) …

Metal–Organic Frameworks For Enzyme Immobilization: Beyond Host Matrix Materials, Xiaoliang Wang, Pui Ching Lan, Shengqian Ma

Chemistry Faculty Publications

Enzyme immobilization in metal–organic frameworks (MOFs) as a promising strategy is attracting the interest of scientists from different disciplines with the expansion of MOFs’ development. Different from other traditional host materials, their unique strengths of high surface areas, large yet adjustable pore sizes, functionalizable pore walls, and diverse architectures make MOFs an ideal platform to investigate hosted enzymes, which is critical to the industrial and commercial process. In addition to the protective function of MOFs, the extensive roles of MOFs in the enzyme immobilization are being well-explored by making full use of their remarkable properties like well-defined structure, high porosity, …

Covalent Organic Frameworks: Opportunities Of Covalent Organic Frameworks For Advanced Applications, Yanpei Song, Qi Sun, Briana Aguila, Shengqian Ma

Chemistry Faculty Publications

Covalent organic frameworks (COFs) are an emerging class of functional nanostructures with intriguing properties, due to their unprecedented combination of high crystallinity, tunable pore size, large surface area, and unique molecular architecture. The enormous possible design space available within COFs provides virtually unlimited room for imagination, allowing designed incorporation of different functionalities. In article number 1801410, Qi Sun, Shengqian Ma, and co-workers review the recent advancements of COFs for numerous applications.

Construction Of A Cross-Layer Linked G-Octamer Via Conformational Control: A Stable G-Quadruplex In H-Bond Competitive Solvents, Ying He, Yanbin Zhang, Lukasz Wojtas, Novruz G. Akhmedov, David Thai, Heng Wang, Xiaopeng Li, Hao Guo, Xiaodong Shi

Chemistry Faculty Publications

Methanol soluble and stable guanosine octamers were successfully achieved via H-bond self-assembly. Through structural conformational design, we developed a new class of guanosine derivatives with modification on guanine (8-aryl) and ribose (2′,3′-isopropylidene). This unique design led to the formation of the first discrete G₈-octamer with its structure characterized by single crystal X-ray diffraction, MS and NMR spectroscopy. The G₈-octamer showed unique cation recognition properties, including the formation of a stable Rb⁺ templated G-quadruplex. Based on this observation, further modification on the 8-aryl moiety was performed to incorporate a cross-layer H-bond or covalent linkage. Similar G-octamers …

Iridium Complex Immobilization On Covalent Organic Framework For Effective C—H Borylation, Harsh Vardhan, Yanxiong Pan, Zhongyu Yang, Gaurav Verma, Ayman Nafady, Abdullah M. Al-Enizi, Tawfiq M. Alotaibi, Omar A. Almaghrabi, Shengqian Ma

Chemistry Faculty Publications

The strong coordination between metal ions and binding moieties in functional porous materials is central to the design and advancement of heterogeneous catalysis. In this study, we have successfully immobilized catalytically active iridium ions on a two-dimensional covalent organic framework (COF) having bipyridine moieties using a programmed synthetic procedure. The iridium immobilized framework, Ir_cod(I)@Py-2,2′-BPyPh COF, had high porosity, good stability, and exhibited excellent catalytic activity for C—H borylation, as compared with the pristine framework. Additionally, Ir_cod(I)@Py-2,2′-BPyPh COF was found to be an efficient catalyst for a series of electronically and sterically substituted substrates. The immobilized COF …

The Modulation Of Actin Dynamics Via Atypical Protein Kinase-C Activated Cofilin Regulates Metastasis Of Colorectal Cancer Cells, S. M. Anisul Islam, Rekha Patel, Raja Reddy Bommareddy, Khandker Mohammad Khalid, Mildred Acevedo-Duncan

Chemistry Faculty Publications

Colorectal cancer (CRC) is the third most common cancer in the United States. The exact mechanism of CRC cells metastasis is poorly understood. Actin polymerization is thought to be an initial step in the cancer cell motility cycle which drives the formation of cell protrusions and defines the direction of migration. Cofilin, a significant actin-regulating molecule, regulates the migration of cancer cells by the formation of lamellipodia and filopodia, however, little is known about the upstream regulation of cofilin. In this study, the effect of atypical Protein Kinase C (atypical PKC) on Cofilin activity in CRC was studied. This study …

Analysis Of Pkc‑Ζ Protein Levels In Normal And Malignant Breast Tissue Subtypes, Tracess Smalley, S. M. Anisul Islam, Christopher Apostolatos, André Apostolatos, Mildred Acevedo-Duncan

Chemistry Faculty Publications

It is estimated that breast cancer will be the second leading cause of cancer‑associated mortality in women in 2018. Previous research has demonstrated that the atypical protein kinase C‑ζ (PKC‑ζ) is a component of numerous dysregulated pathways in breast cancer, including cellular proliferation, survival, and cell cycle upregulation. The present study investigated the PKC‑ζ protein in breast tissue to evaluate its potential as a biomarker for breast cancer invasion, and demonstrated that an overexpression of PKC‑ζ protein can be indicative of carcinogenesis. The present study analyzed the expression of PKC‑ζ in individuals with no tumor complications and malignant female human …

Polycofs: A New Class Of Freestanding Responsive Covalent Organic Framework Membranes With High Mechanical Performance, Zhifang Wang, Qi Yu, Yubo Huang, Hongde An, Yu Zhao, Yifan Feng, Xia Li, Xinlei Shi, Jiajie Liang, Fusheng Pan, Peng Cheng, Yao Chen, Shengqian Ma, Zhenjie Zhang

Chemistry Faculty Publications

Traditional covalent organic frameworks (COFs) are prepared via polymerization based on small molecular monomers. However, the employment of polymers as building blocks to construct COFs has not been reported yet. Herein, we create a new concept of polymer covalent organic frameworks (polyCOFs) formed by linear polymers as structural building blocks, which inherit the merits from both COFs and linear polymers. PolyCOFs represent a new category of porous COF materials that demonstrate good crystallinity and high stability. More importantly, benefiting from the flexibility and processability of a linear polymer, polyCOFs can spontaneously form defect-free, flexible, and freestanding membranes that exhibit excellent …

Construction And Interconversion Of Anion-Coordination-Based (‘Aniono’) Grids And Double Helicates Modulated By Counter-Cations, Xiaoxia Fan, Dan Zhang, Shiyu Jiang, Heng Wang, Lin-Ting Lin, Bo Zheng, Wen-Hua Xu, Yanxia Zhao, Benjamin P. Hay, Yi-Tsu Chan, Xiao-Juan Yang, Xiaopeng Li, Biao Wu

Chemistry Faculty Publications

Supramolecular assembly of well-defined discrete architectures has been of great interest due to the tunable properties of these structures in functional materials and bio-mimicking. While metal-coordination-driven assembly has been extensively studied, anion-coordination-driven assembly (ACDA) is just emerging for constructing complex supramolecular structures. Herein two A_2nL_2n (A = anion, L = ligand; n = 1 or 2) ‘aniono’-supramolecular assemblies, i.e. double helicates and the first anion grid, have been constructed based on the coordination between phosphate (PO₄³⁻) anion and a bis–tris(urea) ligand. Moreover, the aniono-grid and double helicate motifs can be readily interconverted …

Opportunities Of Covalent Organic Frameworks For Advanced Applications, Yanpei Song, Qi Sun, Briana Aguila, Shengqian Ma

Chemistry Faculty Publications

Covalent organic frameworks (COFs) are an emerging class of functional nanostructures with intriguing properties, due to their unprecedented combination of high crystallinity, tunable pore size, large surface area, and unique molecular architecture. The range of properties characterized in COFs has rapidly expanded to include those of interest for numerous applications ranging from energy to environment. Here, a background overview is provided, consisting of a brief introduction of porous materials and the design feature of COFs. Then, recent advancements of COFs as a designer platform for a plethora of applications are emphasized together with discussions about the strategies and principles involved. …

Solvent-Assisted Coordination Driven Assembly Of A Supramolecular Architecture Featuring Two Types Of Connectivity From Discrete Nanocages, Zheng Niu, Lei Wang, Sheng Fang, Pui Ching Lan, Briana Aguila, Jason Perman, Jian-Gong Ma, Peng Cheng, Xiaopeng Li, Shengqian Ma

Chemistry Faculty Publications

The rapid development of supramolecular chemistry provides a powerful bottom-up approach to construct various well-defined nano-architectures with increasing complexity and functionality. Compared to that of small and simple nanometric objects, the self-assembly of larger and more complex nanometric objects, such as nanocages, remains a significant challenge. Herein, we used a discrete nanocage as the monomer to successfully construct a novel three-dimensional (3D) supramolecular architecture, which comprises two types of nanocage building units with different connectivity, using the solvent-assisted coordination-driven assembly approach. The mechanism of this supramolecular assembly process was investigated by electrospray ionization mass spectrometry (ESI-MS) studies, which identified for …

Inhibition Of Human Dendritic Cell Er Stress Response Reduces T Cell Alloreactivity Yet Spares Donor Anti-Tumor Immunity, Brian C. Betts, Frederick L. Locke, Elizabeth M. Sagatys, Joseph Pidala, Kelly Walton, Meghan Menges, Jordan Reff, Asim Saha, Julie Y. Djeu, Chang Won Kang

Chemistry Faculty Publications

Acute graft- vs. -host disease (GVHD) is an important cause of morbidity and death after allogeneic hematopoietic cell transplantation (HCT). We identify a new approach to prevent GVHD that impairs monocyte-derived dendritic cell (moDC) alloactivation of T cells, yet preserves graft- vs.-leukemia (GVL). Exceeding endoplasmic reticulum (ER) capacity results in a spliced form of X-box binding protein-1 (XBP-1s). XBP-1s mediates ER stress and inflammatory responses. We demonstrate that siRNA targeting XBP-1 in moDCs abrogates their stimulation of allogeneic T cells. B-I09, an inositol-requiring enzyme-1α (IRE1α) inhibitor that prevents XBP-1 splicing, reduces human moDC migration, allo-stimulatory potency, and curtails moDC IL-1β, …

Exploitation Of Mangrove Endophytic Fungi For Infectious Disease Drug Discovery, Danielle H. Demers, Matthew A. Knestrick, Renee Fleeman, Rahmy Tawfik, Ala Azhari, Ashley Souza

Chemistry Faculty Publications

There is an acute need for new and effective agents to treat infectious diseases. We conducted a screening program to assess the potential of mangrove-derived endophytic fungi as a source of new antibiotics. Fungi cultured in the presence and absence of small molecule epigenetic modulators were screened against Mycobacterium tuberculosis and the ESKAPE panel of bacterial pathogens, as well as two eukaryotic infective agents, Leishmania donovani and Naegleria fowleri. By comparison of bioactivity data among treatments and targets, trends became evident, such as the result that more than 60% of active extracts were revealed to be selective to a …

Bm-Iaanat And Its Potential Role In Fatty Acid Amide Biosynthesis In Bombyx Mori, Ryan L. Anderson, Matthew R. Battistini, Dylan J. Wallis, Christopher Shoji, Brian G. O'Flynn, John E. Dillashaw, David J Merkler

Chemistry Faculty Publications

The purpose of this research is to unravel the substrate specificity and kinetic properties of an insect arylalkylamine N-acyltransferase from Bombyx mori (Bm-iAANAT) and to determine if this enzyme will catalyze the formation of long chain N-acylarylalkylamides in vitro. However, the determination of substrates and products for Bm-iAANAT in vitro is no guarantee that these same molecules are substrates and products for the enzyme in the organism. Therefore, RT-PCR was performed to detect the Bm-iAANAT transcripts and liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QToF-MS) analysis was performed on purified lipid extracts from B. …

A Novel Gene Expression Analytics-Based Approach To Structure Aided Design Of Rexinoids For Development As Next-Generation Cancer Therapeutics, Bentley J. Hanish, Jennifer F. Hackney Price, Ichiro Kaneko, Ning Ma, Arjan Van Der Vaart, Carl E. Wagner, Peter W. Jurutka, Pamela A. Marshall

Chemistry Faculty Publications

Rexinoids are powerful ligands that bind to retinoid-X-receptors (RXRs) and show great promise as therapeutics for a wide range of diseases, including cancer. However, only one rexinoid, bexarotene (Targretin TM) has been successfully transitioned from the bench to the clinic and used to treat cutaneous T-cell lymphoma (CTCL). Our goal is to develop novel potent rexinoids with a less untoward side effect profile than bexarotene. To this end, we have synthesized a wide array of rexinoids with EC50 values and biological activity similar to bexarotene. In order to determine their suitability for additional downstream analysis, and to identify potential candidate …

Lipidated Α/Α-Aa Heterogeneous Peptides As Antimicrobial Agents, Sylvia Singh, Alekhya Nimmagadda, Ma Su, Minghui Wang, Peng Teng, Jianfeng Cai

Chemistry Faculty Publications

With an increase of resistance in bacteria there is an urgent need for alternative treatment methods that could complement conventional antibiotics. In the past two decades, focus has been drawn to Host Defense Peptides (HDPs) as potential antibiotic agents. Herein we reported our studies on the development of lipidated α/α-AA heterogeneous peptides as a new class of HDP mimetics. These compounds showed potent antimicrobial activity toward both Gram-positive and Gram-negative bacteria, and they also displayed excellent selectivity as they only exhibited limited hemolytic activity. The fluorescence microscopy suggested that the mechanism of action of these heterogeneous peptides is …

Facilely Accessible Quinoline Derivatives As Potent Antibacterial Agents, Peng Teng, Chunhui Li, Zhong Peng, Anne Marie Vanderschouw, Alekhya Nimmagadda, Ma Su, Yaqiong Li, Xingmin Sun, Jianfeng Cai

Chemistry Faculty Publications

Quinoline compounds have been extensively explored as anti-malaria and anti-cancer agents for decades and show profound functional bioactivities, however, the studies of these compounds in other medicinal fields have lagged dramatically. In this study, we report the development of a series of facilely accessible quinoline derivatives that display potent antibacterial activity against a panel of multidrug-resistant Gram-positive bacterial strains, especially C. difficile. We also demonstrated that these molecules are effective in vivo against C. difficile. These results revealed that these types of quinoline compounds could serve as prototypes for the development of an appealing class of antibiotic …

De Novo Left‐Handed Synthetic Peptidomimetic Foldamers, Fengyu She, Peng Teng, Alfredo Peguero-Tejada, Minghui Wang, Ning Ma, Timothy Odom, Mi Zhou, Erald Gjonaj, Lukasz Wojtas, Arjan Van Der Vaart, Jianfeng Cai

Chemistry Faculty Publications

The development of peptidomimetic helical foldamers with a wide repertoire of functions is of significant interest. Herein, we report the X‐ray crystal structures of a series of homogeneous l‐sulfono‐γ‐AA foldamers and elucidate their folding conformation at the atomic level. Single‐crystal X‐ray crystallography revealed that this class of oligomers fold into unprecedented dragon‐boat‐shaped and unexpected left‐handed helices, which are stabilized by the 14‐hydrogen‐bonding pattern present in all sequences. These l‐sulfono‐γ‐AApeptides have a helical pitch of 5.1 Å and exactly four side chains per turn, and the side chains lie perfectly on top of each other along the helical axis. 2D NMR …

Insect Arylalkylamine N-Acyltransferases: Mechanism And Role In Fatty Acid Amide Biosynthesis, Brian G. O'Flynn, Gabriela Suarez, Aidan J. Hawley, David J. Merkler

Chemistry Faculty Publications

Arylalkylamine N-acyltransferases (AANATs) catalyze the formation of an N-acylamide from an acyl-CoA thioester and an amine. One well known example is the production of N-acetylserotonin from acetyl-CoA and serotonin, a reaction in the melatonin biosynthetic pathway from tryptophan. AANATs have been identified from a variety of vertebrates and invertebrates. Considerable efforts have been devoted to the mammalian AANAT because a cell-permeable inhibitor specifically targeted against this enzyme could prove useful to treat diseases related to dysfunction in melatonin production. Insects are an interesting model for the study of AANATs because more than one isoform is typically expressed …

Iodine-Catalyzed Diazo Activation To Access Radical Reactivity, Pan Li, Jingjing Zhao, Lijun Shi, Jin Wang, Xiaodong Shi, Fuwei Li

Chemistry Faculty Publications

Transition-metal-catalyzed diazo activation is a classical way to generate metal carbene, which are valuable intermediates in synthetic organic chemistry. An alternative iodine-catalyzed diazo activation is disclosed herein under either photo-initiated or thermal-initiated conditions, which represents an approach to enable carbene radical reactivity. This metal-free diazo activation strategy were successfully applied into olefin cyclopropanation and epoxidation, and applying this method to pyrrole synthesis under thermal-initiated conditions further demonstrates the unique reactivity using this method over typical metal-catalyzed conditions.

Readily Accessible Shape-Memory Effect In A Porous Interpenetrated Coordination Network, Mohana Shivanna, Qing-Yuan Yang, Alankriti Bajpai, Susan Sen, Nobuhiko Hosono, Shinpei Kusaka, Tony Pham, Katherine A. Forrest, Brian Space, Susumu Kitagawa, Michael J Zaworotko

Chemistry Faculty Publications

Shape-memory effects are quite well-studied in general, but there is only one reported example in the context of porous materials. We report the second example of a porous coordination network that exhibits a sorbate-induced shape-memory effect and the first in which multiple sorbates, N₂, CO₂ and CO promote this effect. The material, a new threefold interpenetrated pcu network, [Zn₂(4,4′-biphenyldicarboxylate)₂(1,4-bis(4-pyridyl)benzene)]_n (X-pcu-3-Zn-3i), exhibits three distinct phases: the as-synthesized α phase; a denser-activated β phase; and a shape-memory γ phase, which is intermediate in density between the α and β phases. The γ phase is …

Theoretical Study Of The Effect Of Halogen Substitution In Molecular Porous Materials For Co2 And C2H2 Sorption, Douglas M. Franz, Mak Djulbegovic, Tony Pham

Chemistry Faculty Publications

Grand canonical Monte Carlo (GCMC) simulations of carbon dioxide (CO₂) and acetylene (C₂H₂) sorption were performed in MPM-1-Cl and MPM-1-Br, two robust molecular porous materials (MPMs) that were synthesized by the addition of adenine to CuX₂ (X = Cl or Br) by solvent diffusion. Previous experimental studies revealed that both MPMs are selective for C₂H₂ over CO₂ [Xie DY, et al. (2017) CIESC J 68: 154–162]. Simulations in MPM-1-Cl and MPM-1-Br were carried out using polarizable and nonpolarizable potentials of the respective sorbates; this was done to investigate the …

Direct Evidence For The Origin Of Bis‐Gold Intermediates: Probing Gold Catalysis With Mass Spectrometry, Mei Lu, Yijin Su, Pengyi Zhao, Xiaohan Ye, Yi Cai, Xiaodong Shi, Eric Masson, Fengyao Li, J. L. Campbell, Hao Chen

Chemistry Faculty Publications

Gold‐catalyzed alkyne hydration was studied by using in situ reacting mass spectrometry (MS) technology. By monitoring the reaction process in solution under different conditions (regular and very diluted catalyst concentrations, different pH values) and examining the reaction occurrence in the early reaction stage (1–2 ms after mixing) with MS, we collected a series of experimental evidence to support that the bis‐gold complex is a potential key reaction intermediate. Furthermore, both experimental and computational studies confirmed that the σ,π‐bis‐gold complexes are not active intermediates toward nucleophilic addition. Instead, formation of geminally diaurated complex C is crucial for this catalytic process.