Abstract In this work we re-examined the molecular structure of enzymatic poly(gallic acid) (PGAL), for which we identified a multiradical and polyanionic nature, in contrast to a previous assignment where it was mistakenly assumed as a neutral and diamagnetic molecule. Here, we present a profound investigation of its ground-state structure by the use of both experimental and theoretical methods, featuring ESR measurements and quantum chemical computations. It was found that its multiradical nature is remarkably stable thanks to an extended hydrogen bonding network occurring within its structure, with interaction energies in the 3–11 kcal/mol regime, according to DFT computations at the M06-2X/6-311++G** level of theory. This multiradical polymer displays several appealing features, including air, thermal and photostabilities, water solubility and, most remarkably, the fact that it is obtained in a multi-gram scale from the naturally abundant gallic acid in mild and green conditions.
: This review discusses the integration of liquid chromatography (LC), mass spectrometry (MS), and nuclear magnetic resonance (NMR) in the comprehensive analysis of small molecules from complex matrices. We first discuss the steps taken toward making the three technologies compatible, so as to create an efficient analytical platform. The development of online LC-MS-NMR, highlighted by successful applications in the profiling of highly concentrated analytes (LODs 10 μg) is discussed next. This is...
#1Pan Wang(MIT: Massachusetts Institute of Technology)H-Index: 7
#2Sibo Lin(MIT: Massachusetts Institute of Technology)H-Index: 12
Last. Timothy M. Swager(MIT: Massachusetts Institute of Technology)H-Index: 114
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Investigations of magnetism in electronically coupled polyradicals have largely focused on applications in photonic and magnetic devices, wherein radical polymers were found to possess molecularly tunable and cooperative magnetic properties. Radical polymers with nonconjugated insulating backbones have been intensively investigated previously; however the integration of radical species into conducting polymer backbones is at an early stage. We report herein 1,3-bisdiphenylene-2-phenylallyl (BDPA...
Research pertaining to conductive polymers has gained significant traction in recent years, and their applications range from optoelectronics to material science. For all intents and purposes, conductive polymers can be described as Nobel Prize-winning materials, given that their discoverers were awarded the Nobel Prize in Chemistry in 2000. In this review, we seek to describe the chemical forms and functionalities of the main types of conductive polymers, as well as their synthesis methods. We ...
#2Mohammad Rafiee(UW: University of Wisconsin-Madison)H-Index: 20
Last. Shannon S. Stahl(UW: University of Wisconsin-Madison)H-Index: 102
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N-Oxyl compounds represent a diverse group of reagents that find widespread use as catalysts for the selective oxidation of organic molecules in both laboratory and industrial applications. While turnover of N-oxyl catalysts in oxidation reactions may be accomplished with a variety of stoichiometric oxidants, N-oxyl reagents have also been extensively used as catalysts under electrochemical conditions in the absence of chemical oxidants. Several classes of N-oxyl compounds undergo facile redox r...
Last. Miquel Gimeno(UNAM: National Autonomous University of Mexico)H-Index: 18
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Abstract The poly(gallic acid), produced by laccase-mediated oxidation of gallic acid in aqueous media (pH 5.5) to attain a novel material with well-defined molecular structure and high water solubility (500 mg/mL at 25 °C), has been investigated to understand its potential biological activities. In this regard, a biomedical approach based on cytoprotective effect on human fibroblast cells exposed to UV-irradiation in the presence of the polymer has been demonstrated. The results also shows that...
Last. Robert G. Griffin(MIT: Massachusetts Institute of Technology)H-Index: 121
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The efficiency of continuous wave dynamic nuclear polarization (DNP) experiments decreases at the high magnetic fields used in contemporary high-resolution NMR applications. To recover the expected signal enhancements from DNP, we explored time domain experiments such as NOVEL which matches the electron Rabi frequency to the nuclear Larmor frequency to mediate polarization transfer. However, satisfying this matching condition at high frequencies is technically demanding. As an alternative we rep...
#2Alberto Tecante(UNAM: National Autonomous University of Mexico)H-Index: 22
Last. Miquel Gimeno(UNAM: National Autonomous University of Mexico)H-Index: 18
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Poly(gallic acid), a novel polymer obtained by enzymatic polymerization of gallic acid, was successfully cross-linked to carboxymethylcellulose using citric acid as a cross-linker. Non-woven sheets were prepared with the resulting copolymer and their in vitro biocompatibility was assessed. The results on the characterizations of the produced films by mechanical tests, water vapour permeability, contact angle, and antioxidant activity by electronic paramagnetic resonance were adequate for skin ti...
#1Jesús Díaz-Sánchez(UNAM: National Autonomous University of Mexico)H-Index: 2
#2Alberto Rosas-Aburto(UNAM: National Autonomous University of Mexico)H-Index: 4
Last. Miquel Gimeno(UNAM: National Autonomous University of Mexico)H-Index: 18
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Abstract An effective polyaniline-based electrochromic device was successfully achieved using the enzyme-mediated poly (gallic acid) as a polyaniline polymerization template. Poly (gallic acid) proved non-toxic upon the conducted cytotoxicity assays. Thermogravimetric analysis of the novel polyaniline-poly (gallic acid) complex displayed a remarkable increase in thermal stability compared to polyaniline-HCl doped, polyaniline-poly (styrene sulfonate), polyaniline-poly (isobutylene-alt-maleic anh...
Last. Zhongfan Jia(UQ: University of Queensland)H-Index: 35
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There has been a resurgence in the development of new synthetic methods to produce stable organic radical polymers (ORPs) with control over chemical composition and structures. This has resulted from the new applications (e.g. electrochemical energy storage to synergistic therapy in drug delivery) that require sophisticated control over the polymer structural properties to compete in the market. Here, we provide a comprehensive overview of the synthetic strategies for making ORPs, discuss the sy...
The first three decades of my research career closely map the development of neutron scattering techniques for the study of molecular behavior. At the same time, the theoretical understanding of organization and motion of polymer molecules, especially in the bulk state, was developing rapidly and providing many predictions crying out for experimental verification. Neutron scattering is an ideal technique for providing the necessary evidence. This autobiographical essay describes the applications...
Abstract Intra-molecular hydrogen bond modulation of compounds positively impacts their solubility, permeability and as well as potency in the field of medicinal chemistry. Herein, N-substituted benzylidene acetohydrazide derivative: (Z)-2-((6-chloropyridin-2-yl)oxy)-N'-(2-hydroxy-3-methoxybenzylidene)acetohydrazide (HOBAH), a novel solid state network was synthesized efficiently via sono-chemical approach. The structural characterization of HOBAH was achieved by single crystal analysis which ex...
Last. Miquel Gimeno(UNAM: National Autonomous University of Mexico)H-Index: 18
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Abstract Microwave-mediated grafting of L-Arg onto naturally derived and stable multiradical poly(gallic acid) (PGAL) in aqueous media has been successfully achieved. This polymeric material has no adverse effect in human cells as there is no hemolytic activity upon MTT and Neutral Red assays. The analytical and computational characterization studies carried out in this study describe a helical molecular structure with random incorporation of L-Arginine pendant groups from PGAL's backbone. The a...
Last. Miquel Gimeno(UNAM: National Autonomous University of Mexico)H-Index: 18
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Abstract Enzymatic mediated poly (gallic acid) (PGAL), a stable multiradical polyanion with helicoidal secondary structure and high antioxidant capacity, was successfully grafted to poly(e-caprolactone) (PCL) using UV-photo induction. PCL films were prepared with several levels of roughness and subsequently grafted with PGAL (PCL-g-PGAL). The results on the full characterization of the produced materials by mechanical tests, surface morphology, and topography, thermal and crystallographic analys...
#2Pablo Labra-Vázquez(UNAM: National Autonomous University of Mexico)H-Index: 5
Last. Miquel Gimeno(UNAM: National Autonomous University of Mexico)H-Index: 18
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A nanocomposite based on an antibiotic-loaded hydrogel into a nano-electrospun fibre with antimicrobial and antioxidant capacities is investigated. The material is composed of nanofibres of enzymatic PCL grafted with poly(gallic acid) (PGAL), a recently developed enzyme-mediated hydrophilic polymer that features a multiradical and polyanionic nature in a helicoidal secondary structure. An extensive experimental–theoretical study on the molecular structure and morphological characterizations for ...
Bioelectronics requires versatile, efficient, and low-cost interfaces between the biological entities and the conductive unit. Conductive polymers represent a valid choice to assemble such interfaces able to extract or impinge charges between the biological units and the conductive electronic systems. A drawback in the use of such systems is that the polymerization reaction often takes place in environments whose chemical and physical characteristics clash with the mild conditions required for l...