Multivalency as a Design Criterion in Catalyst Development

Scrimin, Paolo; Cardona, Maria A.; Prieto, C.; Prins, Leonard J.

doi:10.1002/9781119143505.ch7

Cited by 5 publications

(4 citation statements)

References 46 publications

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“…Based on these data, we conclude that the stability of the Ru(II) complex SAMs is generally comparable to that of NBPT SAMs, which is remarkable considering a significantly weaker bonding of carboxylic groups compared to thiolates in general. This exceptional stability can be most probably rationalized via the multivalent nature of the Ru(II) complexes due to the presence of two carboxylic groups. − Adsorbed oxygen on the Au surface might promote further the surface binding of the Ru(II) complexes, as it was reported for the binding of carboxylates to Au(110) . The stability of the studied thiolate SAMs follows the expectation that the less stable ones can be exchanged more easily by Ru(II) complexes.…”

Section: Results and Discussionsupporting

confidence: 59%

Solution-Based Self-Assembly and Stability of Ruthenium(II) Tris-bipyridyl Monolayers on Gold

Küllmer

Endres

Götz

et al. 2021

ACS Appl. Mater. Interfaces

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Ruthenium(II) polypyridyl complexes are commonly applied as photosensitizers in the fields of artificial photosynthesis and light harvesting. Their immobilization on gold surfaces is also of interest for sensing and biological applications. Here, we report the self-assembly of [Ru-(dmbpy) 2 (dcbpy)](PF 6 ) 2 complexes on gold substrates from solution (dmbpy: 4,4′-dimethyl-2,2′-bipyridine; dcbpy: 2,2′-bipyridine-4,4′-dicarboxylic acid). Applying X-ray photoelectron spectroscopy, we demonstrate the formation of self-assembled monolayers (SAMs) of the Ru(II) complexes upon loss of counterions with carboxylate groups oriented toward the gold surface. We investigate the stability of the formed SAMs toward the substitution in solvents with competing aliphatic and aromatic thiols such as 4′-nitro[1,1′-biphenyl]-4-thiol, [1,1′-biphenyl]-4-thiol, and 1-hexadecanethiol. We show that the exchange reactions may lead to both complete replacement of the Ru(II) complexes and controlled formation of mixed SAMs. Moreover, we demonstrate that thiol-based SAMs can also be replaced completely from gold via their immersion into solutions of [Ru(dmbpy) 2 (dcbpy)](PF 6 ) 2 , indicating a relatively high stability for the Ru(II) complex SAMs. Our findings open up a variety of opportunities for applications of carboxylate-based SAMs on gold in nanotechnology.

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Section: Results and Discussionsupporting

confidence: 59%

Solution-Based Self-Assembly and Stability of Ruthenium(II) Tris-bipyridyl Monolayers on Gold

Küllmer

Endres

Götz

et al. 2021

ACS Appl. Mater. Interfaces

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“…Multimetallic catalysts are more complex multivalent systems, [8] typically showing enhanced activity because of the introduction of a statistical amplification of the interactions with a substrate. [9] Metal ion-functionalized gold nanoparticles (AuNPs) belong to this category. Indeed, they proved to be rather efficient catalysts for the cleavage of phosphodiesters, including RNA model substrates, and DNA as well.…”

Section: Introductionmentioning

confidence: 99%

The Mechanism of Cleavage of RNA Phosphodiesters by a Gold Nanoparticle Nanozyme

Czescik

Mancin

Strömberg

et al. 2021

Chemistry A European J

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The cleavage of uridine 3'-phosphodiesters bearing alcohols with pK a ranging from 7.14 to 14.5 catalyzed by AuNPs functionalized with 1,4,7-triazacyclononane-Zn(II) complexes has been studied to unravel the source of catalysis by these nanosystems (nanozymes). The results have been compared with those obtained with two Zn(II) dinuclear catalysts for which the mechanism is fairly understood. Binding to the Zn(II) ions by the substrate and the uracil of uridine was observed. The latter leads to inhibition of the process and formation of less productive binding complexes than in the absence of the nucleobase. The nanozyme operates with these substrates mostly via a nucleophilic mechanism with little stabilization of the pentacoordinated phosphorane and moderate assistance in leaving group departure. This is attributed to a decrease of binding strength of the substrate to the catalytic site in reaching the transition state due to an unfavorable binding mode with the uracil. The nanozyme favors substrates with better leaving groups than the less acidic ones.

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“…[8][9][10] These synthetic catalysts mimic an enzyme catalytic site by placing together several functions supposed to cooperate in the catalytic process. [11] Quite interesting is the possibility to use multivalent systems [12] that exploit ap latform that can be functionalized with several copies of catalytically active functional groups.T hey not only induce the cooperation of the reactive functions but also,since several catalytic sites are typically present on the same platform, they allow many catalytic events to occur simultaneously. [13] Examples are constituted by dendrimers, [14] micellar and vesicular aggre-gates, [15] carbon dots, [16] polyoxometalates, [17] or nanoparticles.…”

Section: Introductionmentioning

confidence: 99%

A Gold Nanoparticle Nanonuclease Relying on a Zn(II) Mononuclear Complex

et al. 2020

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Similarly to enzymes,f unctionalized gold nanoparticles efficiently catalyze chemical reactions,hence the term nanozymes.H erein, we present our results showing how surface-passivated gold nanoparticles behave as synthetic nanonucleases,a ble to cleave pBR322 plasmid DNAwith the highest efficiency reported so far for catalysts based on asingle metal ion mechanism. Experimental and computational data indicate that we have been successful in creating acatalytic site precisely mimicking that suggested for natural metallonucleases relying on as ingle metal ion for their activity.I tc omprises one Zn(II) ion to which ap hosphate diester of DNAi s coordinated. Importantly,a si nn ucleic acids-processing enzymes,apositively charged arginine playsakey role by assisting with transition state stabilization and by reducing the pK a of the nucleophilic alcohol of as erine.O ur results also show howd esigning ac atalyst for am odel substrate (bis-pnitrophenylphosphate) may provide wrong indications as for its efficiency when it is tested against the real target (plasmid DNA).

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Multivalency as a Design Criterion in Catalyst Development

Cited by 5 publications

References 46 publications

Solution-Based Self-Assembly and Stability of Ruthenium(II) Tris-bipyridyl Monolayers on Gold

Solution-Based Self-Assembly and Stability of Ruthenium(II) Tris-bipyridyl Monolayers on Gold

The Mechanism of Cleavage of RNA Phosphodiesters by a Gold Nanoparticle Nanozyme

A Gold Nanoparticle Nanonuclease Relying on a Zn(II) Mononuclear Complex

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