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Your search keyword '"Workentin, Mark S."' showing total 10 results
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10 results on '"Workentin, Mark S."'

1. Nanocomposites of ferrocenyl-modified gold clusters and semiconducting polymers that integrate field-effect transistor and flash memory in a single neuromorphic device

Author

Singh, Deepa, Gunawardene, Praveen N., Workentin, Mark S., and Fanchini, Giovanni

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

We demonstrate that electroactive thin films incorporating semiconducting polymers and deterministic functionalized gold nanoclusters (ncAu25) lead to integration of the functions of resistive memory device and field-effect transistor (FETs) within a single component (mem-transistor) in a neuromorphic system. Memristor functions originate from ferrocenyl-modified gold nanoclusters (ncAu25-Fc) embedded in polymethyl-methacrylate (PMMA) and devices optimized for maximum 1/0 'flash' memory effect are found to contain 15 wt% ncAu25-Fc. Integrated memristor and neuromorphic functions are obtained by replacing PMMA with poly(3-hexylthiophene) (P3HT) in the active layer, from which transistor effects are derived. Based on the energy band diagrams of ncAu25, PMMA and P3HT, percolation theory is used to explain the memristor 1/0 on/off ratio as a function of ncAu25-Fc concentration. The use of ncAu25-Fc with charge-tunable, ferrocene-modified, ligands is critical toward better cluster-polymer interfaces. Our work shows that nanostructures of polymers and metalorganic frameworks bear strong potential towards neuromorphic devices and the circuital simplification of data storage technology., Comment: The following article has been accepted in Applied Physics Letters. After it is published, it will be found at https://pubs.aip.org/aip/apl with DOI 10.1063/5.0219013 Copyright (2024) D. Singh, P.N. Gunawardene, M.S. Workentin & G. Fanchini. This article is distributed under a CC BY-NC-ND License. https://creativecommons.org/licenses/by-nc-nd/4.0. 15 pages, 5 figures

Published
2024
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6. Controlling the Structure, Properties and Surface Reactivity of Clickable Azide‐Functionalized Au25(SR)18 Nanocluster Platforms Through Regioisomeric Ligand Modifications.

Author

Gunawardene, Praveen N., Martin, Julia, Wong, Jonathan M., Ding, Zhifeng, Corrigan, John F., and Workentin, Mark S.

Subjects
SURFACE properties, AZIDO group, MOLECULAR structure, ISOMERS, X-ray diffraction, RING formation (Chemistry), STRONTIUM ions, METAL clusters
Abstract

To fine‐tune structure–property correlations of thiolate‐protected gold nanoclusters through post‐assembly surface modifications, we report the synthesis of the o, m, and p regioisomeric forms of the anionic azide‐functionalized [Au25(SCH2CH2‐C6H4‐N3)18]1− platform. They can undergo cluster–surface strain‐promoted alkyne–azide cycloaddition (CS‐SPAAC) chemistry with complementary strained‐alkynes. Although their optical properties are similar, the electrochemical properties appear to correlate with the position of the azido group. The ability to conduct CS‐SPAAC chemistry without altering the parent nanocluster structure is different as the isomeric form of the surface ligand is changed, with the [Au25(SCH2CH2‐p‐C6H4‐N3)18]1− isomer having the highest reaction rates, while the [Au25(SCH2CH2‐o‐C6H4‐N3)18]1− isomer is not stable following CS‐SPAAC. Single‐crystal X‐ray diffraction provide the molecular structure of the neutral forms of the three regioisomeric clusters, [Au25(SCH2CH2‐o/m/p‐C6H4‐N3]0, which illustrates correlated structural features of the central core as the position of the azido moiety is changed. [ABSTRACT FROM AUTHOR]

Published
2022
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8. Dialkynylborane Complexes of Formazanate Ligands: Synthesis, Electronic Properties, and Reactivity

Author

Van Belois, Alex, Maar, Ryan R., Workentin, Mark S., and Gilroy, Joe B.

Abstract

Dialkynylborane complexes of N-donor ligands have received significant attention because of their application in biological imaging, as light-harvesting materials, and as the functional component of organic photovoltaics. Despite these advances, relatively few types of N-donor ligands have been explored in this context. To this end, we prepared a series of dialkynylborane complexes of formazanate ligands and explored their electronic properties and reactivity. In doing so, we demonstrated that (1) the nature of the alkynyl substituents has little influence over the UV–vis absorption properties of the title complexes, but does affect the potentials at which they are electrochemically oxidized and reduced, (2) dialkynylborane formazanate complexes can be converted to stable radical anions by chemical reduction with cobaltocene derivatives, and (3) copper-assisted alkyne–azide cycloaddition chemistry at the alkynyl substituents directly bound to boron can be used to elaborate structural diversity. These conclusions are likely to lead to the development of, and provide guiding principles for the design of, future examples of functional molecular materials based on boron complexes of N-donor ligands.

Published
2024
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9. Colloidosomes as a Protocell Model: Engineering Life‐Like Behaviour through Organic Chemistry

Author

Jun Hyeong Park, Agostino Galanti, India Ayling, Sebastien Rochat, Mark S. Workentin, Pierangelo Gobbo, Hyeong Park, Jun, Galanti, Agostino, Ayling, India, Rochat, Sebastien, Workentin, Mark S., and Gobbo, Pierangelo

Subjects
Colloidosome, Protocell, bottom-up synthetic biology, organic chemistry, supramolecular chemistry, soft materials, Organic Chemistry, Physical and Theoretical Chemistry
Abstract

The bottom-up synthesis of self-assembled micro-compartmentalised systems that mimic basic characteristics of living cells is rapidly evolving. These types of systems are termed “protocells” and can be chemically programmed to grow and divide, to send and receive chemical signals, to transcript and translate chemical information, to adhere to surfaces or to other protocells, and to perform rudimental enzyme-mediated metabolic processes. An emerging protocell model that is attracting great attention is the colloidosome. Colloidosomes are microcapsules with a chemically crosslinked, semipermeable membrane composed of amphiphilic nanoparticles. Colloidosomes display important advantages over other protocell models (e. g., vesicles and coacervate micro-droplets) due to their physical-chemical properties that can be easily tuned through the careful engineering of their synthetic building blocks. In this review, we deliver an overview of the different types of colloidosomes that have been developed thus far and discuss how organic chemistry contributes to the design and bottom-up synthesis of novel types of colloidosomes endowed with advanced chemically programmed bio-inspired functions.

Published
2022

10. Ag 20 Nanoclusters with Surface Azides as an Easily Functionalized Platform for Diverse Chemical Applications.

Author

Stöckli AH, de Jong JA, Vega Verduga C, Vogeler NH, Hesari M, Boyle PD, Corrigan JF, and Workentin MS

Abstract

Modifying atomically precise nanocluster surfaces while maintaining the cluster core remains a key challenge. Herein, the synthesis, structure, and properties of two targeted Ag 20 nanoclusters (NCs) with eight surface azide moieties, [CO 3 @Ag 20 (S t Bu) 10 (m-N 3 -C 6 H 4 COO) 8 (DMF) 4 ] (1-m) and [CO 3 @Ag 20 (S t Bu) 10 (p-N 3 -C 6 H 4 COO) 8 (DMF) 4 ] (1-p) are reported, where DMF is N,N-dimethylformamide. These AgNCs are designed to undergo cluster surface strain-promoted azide-alkyne cycloaddition (CS-SPAAC) reactions, introducing new functionality to the cluster surface. Reactivity is screened using model strained cyclooctynes. Reaction products and parent clusters are characterized by UV-vis, FT-IR, and NMR spectroscopies. The structure of the parent clusters and presence of surface azides is confirmed by single crystal X-ray diffraction (SCXRD) analysis. Clusters 1-m and 1-p are found to be amenable to CS-SPAAC reactions with retention of the NC frameworks, opening new routes for efficient modification of AgNC for applications., (© 2024 The Author(s). Small published by Wiley‐VCH GmbH.)

Published
2024
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