School of Chemistry - Research Publications

Permanent URI for this collection

http://hdl.handle.net/11343/300

Filters

2020 2
2
Reset filters

Settings
Statistics
Citations
Author: Gomez, Daniel × Start date: 2020 × End date: 2022 ×

Search Results

Now showing 1 - 2 of 2
  • Item
    Thumbnail Image
    A Tunable Polymer-Metal Based Anti-Reflective Metasurface
    Brasse, Y ; Ng, C ; Magnozzi, M ; Zhang, H ; Mulvaney, P ; Fery, A ; Gomez, DE (WILEY-V C H VERLAG GMBH, 2020-01)
    Anti-reflective surfaces are of great interest for optical devices, sensing, photovoltaics, and photocatalysis. However, most of the anti-reflective surfaces lack in situ tunability of the extinction with respect to wavelength. This communication demonstrates a tunable anti-reflective surface based on colloidal particles comprising a metal core with an electrochromic polymer shell. Random deposition of these particles on a reflective surface results in a decrease in the reflectance of up to 99.8% at the localized surface plasmon resonance frequency. This narrow band feature can be tuned by varying the pH or by application of an electric potential, resulting in wavelength shifts of up to 30 nm. Electrophoretic particle deposition is shown to be an efficient method for controlling the interparticle distance and thereby further optimizing the overall efficiency of the anti-reflective metasurface.
  • Item
    Thumbnail Image
    Photoexcited Pd(ii) auxiliaries enable light-induced control in C(sp3)-H bond functionalisation
    Czyz, ML ; Weragoda, GK ; Horngren, TH ; Connell, TU ; Gomez, D ; O'Hair, RAJ ; Polyzos, A (ROYAL SOC CHEMISTRY, 2020-03-07)
    Herein we report the photophysical and photochemical properties of palladacycle complexes derived from 8-aminoquinoline ligands, commonly used auxiliaries in C-H activation. Spectroscopic, electrochemical and computational studies reveal that visible light irradiation induces a mixed LLCT/MLCT charge transfer providing access to synthetically relevant Pd(iii)/Pd(iv) redox couples. The Pd(ii) complex undergoes photoinduced electron transfer with alkyl halides generating C(sp3)-H halogenation products rather than C-C bond adducts. Online photochemical ESI-MS analysis implicates participation of a mononuclear Pd(iii) species which promotes C-X bond formation via a distinct Pd(iii)/Pd(iv) pathway. To demonstrate the synthetic utility, we developed a general method for inert C(sp3)-H bond bromination, chlorination and iodination with alkyl halides. This new strategy in auxiliary-directed C-H activation provides predictable and controllable access to distinct reactivity pathways proceeding via Pd(iii)/Pd(iv) redox couples induced by visible light irradiation.