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Full-Text Articles in Chemistry

Rompi-Cdsa: Ring-Opening Metathesis Polymerization-Induced Crystallization-Driven Self-Assembly Of Metallo-Block Copolymers, Ye Sha, Md Anisur Rahman, Tianyu Zhu, Yujin Cha, C Wayne Mcalister, Chuanbing Tang Sep 2019

Rompi-Cdsa: Ring-Opening Metathesis Polymerization-Induced Crystallization-Driven Self-Assembly Of Metallo-Block Copolymers, Ye Sha, Md Anisur Rahman, Tianyu Zhu, Yujin Cha, C Wayne Mcalister, Chuanbing Tang

Faculty Publications

Polymerization-induced self-assembly (PISA) and crystallization-driven self-assembly (CDSA) are among the most prevailing methods for block copolymer self-assembly. Taking the merits of scalability of PISA and dimension control of CDSA, we report one-pot synchronous PISA and CDSA ring-opening metathesis polymerization (ROMP) to prepare nano-objects based on a crystalline poly(ruthenocene) motif. We denote this self-assembly methodology as ROMPI-CDSA to enable a simple, yet robust approach for the preparation of functional nanomaterials.


Generalizing Metallocene Mechanochemistry To Ruthenocene Mechanophores, Ye Sha, Yudi Zhang, Enhua Xu, C Wayne Mcalister, Tianyu Zhu, Stephen L. Craig, Chuanbing Tang Apr 2019

Generalizing Metallocene Mechanochemistry To Ruthenocene Mechanophores, Ye Sha, Yudi Zhang, Enhua Xu, C Wayne Mcalister, Tianyu Zhu, Stephen L. Craig, Chuanbing Tang

Faculty Publications

Recent reports have shown that ferrocene displays an unexpected combination of force-free stability and mechanochemical activity, as it acts as the preferred site of chain scission along the backbone of highly extended polymer chains. This observation raises the tantalizing question as to whether similar mechanochemical activity might be present in other metallocenes, and, if so, what features of metallocenes dictate their relative ability to act as mechanophores. In this work, we elucidate polymerization methodologies towards main-chain ruthenocene-based polymers and explore the mechanochemistry of ruthenocene. We find that ruthenocene, in analogy to ferrocene, acts as a highly selective site of main …


Exposure Characterization Of Haloacetic Acids In Humans For Exposure And Risk Assessment Applications: An Exploratory Study, Shahid Parvez, Jeffrey L. Ashby, Susana Y. Kimura, Susan D. Richardson Feb 2019

Exposure Characterization Of Haloacetic Acids In Humans For Exposure And Risk Assessment Applications: An Exploratory Study, Shahid Parvez, Jeffrey L. Ashby, Susana Y. Kimura, Susan D. Richardson

Faculty Publications

Disinfected water is the major source of haloacetic acids (HAAs) in humans, but their inter- and intra-individual variability for exposure and risk assessment applications is under-researched. Thus, we measured HAAs in cross-sectional and longitudinal urine and water specimens from 17 individuals. Five regulated HAAs—mono-, di-, and trichloroacetic acid (MCAA, DCAA, and TCAA) and mono- and dibromoacetic acid (MBAA and DBAA)—and one unregulated HAA—bromochloroacetic acid (BCAA)—were measured. Urinary DCAA, MBAA, DBAA, and BCAA levels were always below the limits of detection (LOD). Measured levels and interindividual variability of urinary MCAA were higher than urinary TCAA. Longitudinal urinary specimens showed MCAA levels …


Metallo-Polyelectrolytes As A Class Of Ionic Macromolecules For Functional Materials, Tianyu Zhu, Ye Sha, Jing Yan, Parasmani Pageni, Md Anisur Rahman, Yi Yan, Chuanbing Tang Oct 2018

Metallo-Polyelectrolytes As A Class Of Ionic Macromolecules For Functional Materials, Tianyu Zhu, Ye Sha, Jing Yan, Parasmani Pageni, Md Anisur Rahman, Yi Yan, Chuanbing Tang

Faculty Publications

The fields of soft polymers and macromolecular sciences have enjoyed a unique combination of metals and organic frameworks in the name of metallopolymers or organometallic polymers. When metallopolymers carry charged groups, they form a class of metal-containing polyelectrolytes or metallo-polyelectrolytes. This review identifies the unique properties and functions of metallo-polyelectrolytes compared with conventional organo-polyelectrolytes, in the hope of shedding light on the formation of functional materials with intriguing applications and potential benefits. It concludes with a critical perspective on the challenges and hurdles for metallo-polyelectrolytes, especially experimental quantitative analysis and theoretical modeling of ionic binding.


Facially Amphiphilic Polyionene Biocidal Polymers Derived From Lithocholic Acid, Mitra S. Ganewatta, Md Anisur Rahman, Louis Mercado, Tinom Shokfai, Alan W. Decho, Theresa M. Reineke, Chuanbing Tang Jun 2018

Facially Amphiphilic Polyionene Biocidal Polymers Derived From Lithocholic Acid, Mitra S. Ganewatta, Md Anisur Rahman, Louis Mercado, Tinom Shokfai, Alan W. Decho, Theresa M. Reineke, Chuanbing Tang

Faculty Publications

Bacterial infections have become a global issue that requires urgent attention, particularly regarding to emergence of multidrug resistant bacteria. We developed quaternary amine-containing antimicrobial poly(bile acid)s that contain a hydrophobic core of lithocholic acid in the main-chain. Interestingly, by choosing appropriate monomers, these cationic polymers can form core-shell micelles. These polymers exhibited biocidal activity against both Gram-positive and Gram-negative bacterial species. It is demonstrated that the micelles can deliver hydrophobic antibiotics that functionally have dual antimicrobial activities. Cytotoxicity assays against HeLa cells showed dosage-dependent toxicity for polymers with longer linkers.


Advancing Professional Development Strategies For Chemistry And Biochemistry Undergraduates, Christian A. Brown Apr 2018

Advancing Professional Development Strategies For Chemistry And Biochemistry Undergraduates, Christian A. Brown

Senior Theses

In the Department of Chemistry and Biochemistry at the University of South Carolina (the Department), most curriculum-driven professional development is reserved for third- and fourth-year students. Classroom learning occurs at all levels, but the context comes late. Early exposure to career options and hands-on training is imperative for undergraduates to obtain maximum experiential learning. The purpose of this project is to advance the current professional development strategies of the Department, specifically targeting second- and third-year students. The study surveyed students' current involvement in professional development activities. The data on extracurricular experience and post-graduation interest was used to design a workshop …


Expansion Of The (Bb)>Ru Metallacycle With Coinage Metal Cations: Formation Of B-M-Ru-B (M= Cu, Ag, Au) Dimetalacyclodiboryls†, Bennett J. Eleazer, Mark D. Smith, Alexey A. Popov, Dmitry V. Peryshkov Feb 2018

Expansion Of The (Bb)>Ru Metallacycle With Coinage Metal Cations: Formation Of B-M-Ru-B (M= Cu, Ag, Au) Dimetalacyclodiboryls†, Bennett J. Eleazer, Mark D. Smith, Alexey A. Popov, Dmitry V. Peryshkov

Faculty Publications

In this work, we introduce a novel approach for the selective assembly of heterometallic complexes by unprecedented coordination of coinage metal cations to strained single ruthenium–boron bonds on a surface of icosahedral boron clusters. M(I) cations (M ¼ Cu, Ag, and Au) insert into B–Ru bonds of the (BB)–carboryne complex of ruthenium with the formation of four-membered B–M–Ru–B metalacycles. Results of theoretical calculations suggest that bonding within these metalacycles can be best described as unusual three-center-two-electron B–M/Ru interactions that are isolobal to B–H/Ru borane coordination for M ¼ Cu and Ag, or the pairs of two-center-two electron B–Au and Au–Ru …


Hydrogen-Bonding-Directed Ordered Assembly Of Carboxylated Poly(3-Alkylthiophene)S, David W. Bilger, Jose A. Figueroa, Neil D. Redeker, Amrita Sarkar, Morgan Stefik, Shanjuu Zhang Nov 2017

Hydrogen-Bonding-Directed Ordered Assembly Of Carboxylated Poly(3-Alkylthiophene)S, David W. Bilger, Jose A. Figueroa, Neil D. Redeker, Amrita Sarkar, Morgan Stefik, Shanjuu Zhang

Faculty Publications

Hydrogen-bonding-induced ordered assembly of poly(3-alkylthiophene)s derivatives bearing carboxylic acid groups has been investigated from diluted and concentrated solutions to solid films using ultraviolet–visible absorption spectroscopy, polarized optical microscopy, and four-point probe conductivity measurements. In dilute solutions, the polymer undergoes a spontaneous structural transition from disordered coil-like to ordered rodlike conformations, which is evidenced by time-dependent chromism. Many factors such as alkyl-chain length, types of solvents, and temperature are studied to understand the assembly behavior. Transition kinetics of the assembly process reveals a universal second-order rate law, indicating an intermolecular origin due to hydrogen bonding. When more concentrated, hydrogen bonding drives …


Blockade Of Cb1 Cannabinoid Receptor Alters Gut Microbiota And Attenuates Inflammation And Diet-Induced Obesity, Pegah Mehrpouya-Bahrami, Kumaraswamy Naidu Chitrala, Mitra S. Ganewatta, Chuanbing Tang, E Angela Murphy, Reilly Enos, Kandy T. Velazquez, Jamie Mccellan, Mitzi Nagarkatti, Prakash Nagarkatti Nov 2017

Blockade Of Cb1 Cannabinoid Receptor Alters Gut Microbiota And Attenuates Inflammation And Diet-Induced Obesity, Pegah Mehrpouya-Bahrami, Kumaraswamy Naidu Chitrala, Mitra S. Ganewatta, Chuanbing Tang, E Angela Murphy, Reilly Enos, Kandy T. Velazquez, Jamie Mccellan, Mitzi Nagarkatti, Prakash Nagarkatti

Faculty Publications

Obesity is characterized by chronic low-grade, systemic inflammation, altered gut microbiota, and gut barrier disruption. Additionally, obesity is associated with increased activity of endocannabinoid system (eCB). However, the clear connection between gut microbiota and the eCB system in the regulation of energy homeostasis and adipose tissue inflammation and metabolism, remains to be established. We investigated the effect of treatment of mice with a cannabinoid receptor 1 (CB1) antagonist on Diet-Induced Obesity (DIO), specifically whether such a treatment that blocks endocannabinoid activity can induce changes in gut microbiota and anti-inflammatory state in adipose tissue. Blockade of CB1 attenuated DIO, inflammatory cytokines …


Rapid Reversible Borane To Boryl Hydride Exchange By Metal Shuttling On The Carborane Cluster Surface, Bennett J. Eleazer, Mark D. Smith, Alexey A. Popov, Dmitry V. Peryshkov May 2017

Rapid Reversible Borane To Boryl Hydride Exchange By Metal Shuttling On The Carborane Cluster Surface, Bennett J. Eleazer, Mark D. Smith, Alexey A. Popov, Dmitry V. Peryshkov

Faculty Publications

In this work, we introduce a novel concept of a borane group vicinal to a metal boryl bond acting as a supporting hemilabile ligand in exohedrally metalated three-dimensional carborane clusters. The (POBOP)Ru(Cl)(PPh3) pincer complex (POBOP ¼ 1,7-OP(i-Pr)2-m-2-carboranyl) features extreme distortion of the two-center-two-electron Ru–B bond due to the presence of a strong three-centertwo-electron B–H/Ru vicinal interaction. Replacement of the chloride ligand with a hydride afforded the (POBOP)Ru(H)(PPh3) pincer complex, which possesses B–Ru, B–H/Ru, and Ru–H bonds. This complex was found to exhibit a rapid exchange between hydrogen atoms of the borane and the terminal hydride through metal center shuttling between …


Hierarchical Corannulene-Based Materials: Energy Transfer And Solid-State Photophysics, Allison M. Rice, W. Brett Fellows, Ekaterina A. Dolgopolova, Andrew B. Greytak, Aaron K. Vannucci, Mark D. Smith, Stavros G. Karakalos, Jeanette A. Krause, Stanislav M. Avdoshenko, Alexey A. Popov, Natalia B. Shustova Prof. Dr. Mar 2017

Hierarchical Corannulene-Based Materials: Energy Transfer And Solid-State Photophysics, Allison M. Rice, W. Brett Fellows, Ekaterina A. Dolgopolova, Andrew B. Greytak, Aaron K. Vannucci, Mark D. Smith, Stavros G. Karakalos, Jeanette A. Krause, Stanislav M. Avdoshenko, Alexey A. Popov, Natalia B. Shustova Prof. Dr.

Faculty Publications

We report the first example of a donor–acceptor corannulene-containing hybrid material with rapid ligand-to-ligand energy transfer (ET). Additionally, we provide the first time-resolved photoluminescence (PL) data for any corannulene-based compounds in the solid state. Comprehensive analysis of PL data in combination with theoretical calculations of donor–acceptor exciton coupling was employed to estimate ET rate and efficiency in the prepared material. The ligand-to-ligand ET rate calculated using two models is comparable with that observed in fullerene-containing materials, which are generally considered for molecular electronics development. Thus, the presented studies not only demonstrate the possibility of merging the intrinsic properties of π-bowls, …


Fulleretic Well-Defined Scaffolds: Donor–Fullerene Alignment Through Metal Coordination And Its Effect On Photophysics, Derek E. Williams, Ekaterina A. Dolgopolova, Danielle C. Godfrey, Evgeniya D. Ermolaeva, Perry J. Pellechia Dr., Andrew B. Greytak Prof. Dr., Mark Smith Dr., Stanislav M. Avdoshenko, Dr., Alexey A. Popov Dr., Natalia B. Shustova Prof. Dr. Jul 2016

Fulleretic Well-Defined Scaffolds: Donor–Fullerene Alignment Through Metal Coordination And Its Effect On Photophysics, Derek E. Williams, Ekaterina A. Dolgopolova, Danielle C. Godfrey, Evgeniya D. Ermolaeva, Perry J. Pellechia Dr., Andrew B. Greytak Prof. Dr., Mark Smith Dr., Stanislav M. Avdoshenko, Dr., Alexey A. Popov Dr., Natalia B. Shustova Prof. Dr.

Faculty Publications

Herein, we report the first example of a crystalline metal–donor–fullerene framework, in which control of the donor–fullerene mutual orientation was achieved through chemical bond formation, in particular, by metal coordination. The 13C cross-polarization magic-angle spinning NMR spectroscopy, X-ray diffraction, and time-resolved fluorescence spectroscopy were performed for comprehensive structural analysis and energy-transfer (ET) studies of the fulleretic donor–acceptor scaffold. Furthermore, in combination with photoluminescence measurements, the theoretical calculations of the spectral overlap function, Förster radius, excitation energies, and band structure were employed to elucidate the photophysical and ET processes in the prepared fulleretic material. We envision that the well-defined fulleretic donor–acceptor …


A Supramolecular Strategy To Assemble Multifunctional Viral Nanoparticles, Limin Chen, Xia Zhao, Yuan Lin, Yubin Huang, Qian Wang Aug 2013

A Supramolecular Strategy To Assemble Multifunctional Viral Nanoparticles, Limin Chen, Xia Zhao, Yuan Lin, Yubin Huang, Qian Wang

Faculty Publications

Using a one-pot approach driven by the supramolecular interaction between β-cyclodextrin and adamantyl moieties, multifunctional viral nanoparticles can be facilely formulated for biomedical applications.


An Acid Catalyzed Reversible Ring-Opening/Ring-Closure Reaction Involving A Cyano-Rhodamine Spirolactam, H. Li, H. Guan, X. Duan, J. Hu, Guiren Wang, Qian Wang Jan 2013

An Acid Catalyzed Reversible Ring-Opening/Ring-Closure Reaction Involving A Cyano-Rhodamine Spirolactam, H. Li, H. Guan, X. Duan, J. Hu, Guiren Wang, Qian Wang

Faculty Publications

Cyanamide was introduced into the rhodamine spirolactam framework to produce a colorless and non-fluorescent compound RBCN. It shows a reversible ring-opening/ring-closure process in response to the solution pH, which exhibits an “ON/OFF” switching in its fluorescence. Different from other rhodamine-type dyes, the ring-open form of RBCN is stable in protic solvents under neutral, near neutral and basic conditions, showing a pink color and very strong fluorescence. We also demonstrated the potential of RBCN in live cell imaging.


Breast Tumour Initiating Cell Fate Is Regulated By Microenvironmental Cues From An Extracellular Matrix, Sharmistha Saha, Pang-Kuo Lo, Xinrui Duan, Hexin Chen, Qian Wang Aug 2012

Breast Tumour Initiating Cell Fate Is Regulated By Microenvironmental Cues From An Extracellular Matrix, Sharmistha Saha, Pang-Kuo Lo, Xinrui Duan, Hexin Chen, Qian Wang

Faculty Publications

Cancer stem cells, also known as tumour-initiating cells (TICs), are identified as highly tumorigenic population within tumours and hypothesized to be main regulators in tumour growth, metastasis and relapse. Evidence also suggests that a tumour microenvironment plays a critical role in the development and progression of cancer, by constantly modulating cell–matrix interactions. Scientists have tried to characterize and identify the TIC population but the actual combination of extracellular components in deciphering the fate of TICs has not been explored. The basic unanswered question is the phenotypic stability of this TIC population in a tissue extracellular matrix setting. The in vivo …


Discrimination Of Colon Cancer Stem Cells Using Noncanonical Amino Acid, Xinrui Duan, Honglin Li, Hexin Chen, Qian Wang Jul 2012

Discrimination Of Colon Cancer Stem Cells Using Noncanonical Amino Acid, Xinrui Duan, Honglin Li, Hexin Chen, Qian Wang

Faculty Publications

Cancer stem cells (CSCs) may be responsible for tumor recurrence. Metabolic labelling of newly synthesized proteins with non-canonical amino acids allows us to discriminate CSCs in mixed populations due to the quiescent nature of these cells.


The Mechanical Properties Of Epoxy Composites Filled With Rubbery Copolymer Grafted Sio2, Jianing Gao, Junting Li, Brian C. Benicewicz, Su Zhao, Henrik Hillborg, Linda S. Schadler Jan 2012

The Mechanical Properties Of Epoxy Composites Filled With Rubbery Copolymer Grafted Sio2, Jianing Gao, Junting Li, Brian C. Benicewicz, Su Zhao, Henrik Hillborg, Linda S. Schadler

Faculty Publications

This study demonstrated a method for toughening a highly crosslinked anhydride cured DGEBA epoxy using rubbery block copolymer grafted SiO2 nanoparticles. The particles were synthesized by a sequential reversible addition-fragmentation chain transfer (RAFT) polymerization. The inner rubbery block poly(n-hexyl methacrylate) (PHMA) had a glass transition temperature below room temperature. The outer block poly(glycidyl methacrylate) (PGMA) was matrix compatible. A rubbery interlayer thickness of 100% and 200% of the particle core radius was achieved by grafting a 20 kg/mol and a 40 kg/mol PHMA at a graft density of 0.7 chains/nm2 from the SiO2 surface. The 20 kg/mol rubbery …


Systematic Approach To Electrostatically Induced 2d Crystallization Of Nanoparticles At Liquid Interfaces, Sumit Kewalramani, Suntao Wang, Yuan Lin, Huong Giang Nguyen, Qian Wang, Masafumi Fukuto, Lin Yang Nov 2010

Systematic Approach To Electrostatically Induced 2d Crystallization Of Nanoparticles At Liquid Interfaces, Sumit Kewalramani, Suntao Wang, Yuan Lin, Huong Giang Nguyen, Qian Wang, Masafumi Fukuto, Lin Yang

Faculty Publications

We report an experimental demonstration of a strategy for inducing two-dimensional (2D)crystallization of charged nanoparticles on oppositely charged fluid interfaces. This strategy aims to maximize the interfacial adsorption of nanoparticles, and hence their lateral packing density, by utilizing a combination of weakly charged particles and a high surface charge density on the planar interface. In order to test this approach, we investigated the assembly of cowpea mosaic virus (CPMV) on positively charged lipid monolayers at the aqueous solution surface, by means of in situX-ray scattering measurements at the liquid–vapor interface. Theassembly was studied as a function of the solution …


Oriented Cell Growth On Self-Assembled Bacteriophage M13 Thin Films, Jianhua Rong, L. Andrew Lee, Kai Li, Brandon Harp, Charlene M. Mello, Zhongwei Niu, Qian Wang Sep 2008

Oriented Cell Growth On Self-Assembled Bacteriophage M13 Thin Films, Jianhua Rong, L. Andrew Lee, Kai Li, Brandon Harp, Charlene M. Mello, Zhongwei Niu, Qian Wang

Faculty Publications

Fibrillar M13 bacteriophages were used as basic building blocks to generate thin films with aligned nanogrooves, which, upon chemical grafting with RGD peptides, guide cell alignment and orient the cell outgrowth along defined directions.


1,3,7,10,14,17,21,28,31,42,52,55-Dodeca­Kis(Trifluoro­Meth­Yl)- 1,3,7,10,14,17,21,28,31,42,52,55-Dodeca­Hydro­(C60-IH)[5,6]Fullerene, Natalia B. Shustova Prof. Dr., O.P. Anderson, O. V. Boltalina, S. H. Strauss, I. E. Kareev Nov 2007

1,3,7,10,14,17,21,28,31,42,52,55-Dodeca­Kis(Trifluoro­Meth­Yl)- 1,3,7,10,14,17,21,28,31,42,52,55-Dodeca­Hydro­(C60-IH)[5,6]Fullerene, Natalia B. Shustova Prof. Dr., O.P. Anderson, O. V. Boltalina, S. H. Strauss, I. E. Kareev

Faculty Publications

The title compound, C72F36, is one of four isomers of C60(CF3)12 for which crystal structures have been obtained. The fullerene mol­ecule has an idealized Ih C60 core with the 12 CF3 groups arranged in an asymmetric fashion on two ribbons of edge-sharing C6(CF3)2 hexa­gons, a parametaparaparaparametapara ribbon and a parametapara ribbon, giving an overall pmp 3 mp,pmp structure. There are no cage Csp 3 …