skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: Tandem catalysis using an enzyme and a polymeric ruthenium-based artificial metalloenzyme
A Ru-containing single chain nanoparticle (SCNP) was prepared in three steps using radical polymerization of pentafluorophenylacrylate, post-polymerization functionalization with three different alkylamines, and coordination of Ru. The polymer was characterized by 1 H NMR, 19 F NMR, UV-vis, and DLS. The catalytic activity of the Ru-SCNP for Ru-catalyzed cleavage of allylcarbamates was evaluated by fluorescence spectroscopy and a higher percent conversion and initial rate of reaction was observed when compared to that of the free catalyst in buffer and cell media. The catalytic SCNP was also shown to perform tandem catalysis with β-galactosidase.  more » « less
Award ID(s):
1709718
PAR ID:
10330304
Author(s) / Creator(s):
; ; ;
Date Published:
Journal Name:
Polymer Chemistry
Volume:
12
Issue:
46
ISSN:
1759-9954
Page Range / eLocation ID:
6755 to 6760
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; (, Inorganic Chemistry Frontiers)
    null (Ed.)
    A dimeric yttrium phenoxide complex supported by a ferrocene Schiff base ligand, [(salfen)Y(OPh)] 2 (salfen = ( N,N ′-bis(2,4-di- tert -butylphenoxy)-1,1′-ferrocenediimine), was synthesized and characterized. According to electrochemical studies and 1 H NMR spectroscopy, [(salfen)Y(OPh)] 2 can be oxidized in a stepwise fashion to access three oxidation states. The catalytic activity of the three states toward the ring opening polymerization of cyclic esters and epoxides was investigated. The activity toward cyclic esters decreases upon oxidation while the opposite trend was observed in epoxide polymerization. Block copolymer syntheses using a redox switch were also performed. 
    more » « less
  2. ; ; ; (, ACS Macro Letters)
    The successful polymerization of the Dewar isomer of an azaborinine heterocycle is reported. Controlled ring-opening metathesis polymerization was accomplished with Grubbs and Hoveya−Grubbs second generation catalysts (G2, HG2), as well as a Z-selective Ru catalyst (HGM2001). The structure of the polymers containing 4-membered B−N heterocycles was verified by GPC and multinuclear and 2D NMR. Differences in stereochemistry of polymers derived from G2/HG2 versus the Z-selective catalyst HGM2001 were substantiated by 2D NOESY, FT-IR, and Raman analyses. The incorporation of B−N heterocycles into these polymer structures is promising as a route to functional polymers that contain polar side groups. 
    more » « less
  3. ; ; ; ; (, ChemSusChem)
    Abstract Catalytic water oxidation is an important process for the development of clean energy solutions and energy storage. Despite the significant number of reports on active catalysts, systematic control of the catalytic activity remains elusive. In this study, descriptors are explored that can be correlated with catalytic activity. [Ru(tpy)(pic)2(H2O)](NO3)2and [Ru(EtO‐tpy)(pic)2(H2O)](NO3)2(where tpy=2,2′ : 6′,2“‐terpyridine, EtO‐tpy=4′‐(ethoxy)‐2,2′:6′,2”‐terpyridine, pic=4‐picoline) are synthesized and characterized by NMR, UV/Vis, EPR, resonance Raman, and X‐ray absorption spectroscopy, and electrochemical analysis. Addition of the ethoxy group increases the catalytic activity in chemically driven and photocatalytic water oxidation. Thus, the effect of the electron‐donating group known for the [Ru(tpy)(bpy)(H2O)]2+family is transferable to architectures with a tpy ligandtransto the Ru‐oxo unit. Under catalytic conditions, [Ru(EtO‐tpy)(pic)2(H2O)](NO3)2displays new spectroscopic signals tentatively assigned to a peroxo intermediate. Reaction pathways were analyzed by using DFT calculations. [Ru(EtO‐tpy)(pic)2(H2O)](NO3)2is found to be one of the most active catalysts functioning by a water nucleophilic attack mechanism. 
    more » « less
  4. ; ; ; ; (, Nucleic Acids Research)
    Abstract The RNA World hypothesis posits that RNA was the molecule of both heredity and function during the emergence of life. This hypothesis implies that RNA templates can be copied, and ultimately replicated, without the catalytic aid of evolved enzymes. A major problem with nonenzymatic template-directed polymerization has been the very poor copying of sequences containing rA and rU. Here, we overcome that problem by using a prebiotically plausible mixture of RNA mononucleotides and random-sequence oligonucleotides, all activated by methyl isocyanide chemistry, that direct the uniform copying of arbitrary-sequence templates, including those harboring rA and rU. We further show that the use of this mixture in copying reactions suppresses copying errors while also generating a more uniform distribution of mismatches than observed for simpler systems. We find that oligonucleotide competition for template binding sites, oligonucleotide ligation and the template binding properties of reactant intermediates work together to reduce product sequence bias and errors. Finally, we show that iterative cycling of templated polymerization and activation chemistry improves the yields of random-sequence products. These results for random-sequence template copying are a significant advance in the pursuit of nonenzymatic RNA replication. 
    more » « less
  5. ; ; ; (, Chemical Science)
    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)(PPh 3 ) pincer complex (POBOP = 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-center-two-electron B–H⋯Ru vicinal interaction. Replacement of the chloride ligand with a hydride afforded the (POBOP)Ru(H)(PPh 3 ) 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 two boron atoms of the carborane cage. This exchange process, which involves sequential cleavage and formation of strong covalent metal–boron and metal–hydrogen bonds, is unexpectedly facile at temperatures above −50 °C corresponding to an activation barrier of 12.2 kcal mol −1 . Theoretical calculations suggested two equally probable pathways for the exchange process through formally Ru(0) or Ru( iv ) intermediates, respectively. The presence of this hemilabile vicinal B–H⋯Ru interaction in (POBOP)Ru(H)(PPh 3 ) was found to stabilize a latent coordination site at the metal center promoting efficient catalytic transfer dehydrogenation of cyclooctane under nitrogen and air at 170 °C. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email