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Start Over Author "Southern University of Science and Technology [Shenzhen] (SUSTech)" Publisher royal society of chemistry (rsc)
2 results on '"Southern University of Science and Technology [Shenzhen] (SUSTech)"'

1. The switchable phosphorescence and delayed fluorescence of a new rhodamine-like dye through allenylidene formation in a cyclometallated platinum(<scp>ii</scp>) system

Author

Yifan Zhu, Ling Li, Véronique Guerchais, Julien Boixel, Keith Man-Chung Wong, Shunan Zhao, Harbin Institute of Technology (HIT), Southern University of Science and Technology [Shenzhen] (SUSTech), Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), NSFC-CNRS_PRC Joint Research Projects Program [21911530232], National Natural Science Foundation of China National Natural Science Foundation of China (NSFC) [21771099], Science, Technology and Innovation Commission of Shenzhen Municipality [JCYJ 20170817110721105, JCYJ20190809165411528], CNRS Centre National de la Recherche Scientifique (CNRS) European Commission [20181101321], Southern University of Science and Technology (SUSTech), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
chemistry.chemical_classification, 010405 organic chemistry, Ligand, chemistry.chemical_element, Alkyne, General Chemistry, 010402 general chemistry, Photochemistry, Resonance (chemistry), 01 natural sciences, Fluorescence, 0104 chemical sciences, Rhodamine, Chemistry, chemistry.chemical_compound, chemistry, Excited state, [CHIM]Chemical Sciences, Platinum, Phosphorescence
Abstract

A new rhodamine-like alkyne-substituted ligand (Rhodyne) was designed to coordinate a cyclometallated platinum(ii) system. The chemo-induced “ON–OFF” switching capabilities on the spirolactone ring of the Rhodyne ligand with an end-capping platinum(ii) metal centre can modulate the interesting acetylide–allenylidene resonance. The long-lived 3IL excited state of Rhodyne in its ON state as an optically active opened form was revealed via steady-state and time-resolved spectroscopy studies. Exceptional near-infrared (NIR) phosphorescence and delayed fluorescence based on a rhodamine-like structure were observed at room temperature for the first time. The position of the alkyne communication bridge attached to the platinum(ii) unit was found to vary the lead(ii)-ion binding mode and also the possible resonance structure for metal-mediated allenylidene formation. The formation of a proposed allenylidene resonance structure was suggested to rationalize these phenomena., A new rhodamine-like ligand (Rhodyne) was designed to coordinate a cyclometallated platinum(ii) system. Allenylidene formation could trigger NIR phosphorescence at 740 nm originating from Rhodyne 3IL, as well as delayed fluorescence at 620 nm.

Published
2021

2. Characterising local environments in high energy density Li-ion battery cathodes: a combined NMR and first principles study of LiFexCo1−xPO4

Author

Raphaële J. Clément, Guido Pintacuda, Derek S. Middlemiss, Ago Samoson, Andrew J. Pell, Lyndon Emsley, Fiona C. Strobridge, Frédérique Pourpoint, Michal Leskes, John V. Hanna, Zhouguang Lu, Clare P. Grey, Department of Chemistry, University of Cambridge [UK] (CAM), Institut des Sciences Analytiques (ISA), Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Laboratory of Green and Renewable Energy Materials, Southern University of Science and Technology [Shenzhen] (SUSTech), Department of Physics, University of Warwick [Coventry], Biological Solid-State NMR Methods - Méthodes de RMN à l'état solide en biologie, Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Solid-State NMR Methods for Materials - Méthodes de RMN à l'état solide pour les matériaux, Tehnomeedikum, Tallinn University of Technology (TTÜ), Stony Brook University [SUNY] (SBU), State University of New York (SUNY)-State University of New York (SUNY), and We thank Ben Zhu for his help with the NMR and thoughtful discussions. We also thank the UK EPSRC for a DTA award (FCS) the US DOE for support via NECCES, an Energy Frontier Research Center (DE-SC0001294) (CPG) and the EU ERC for financial support and a Marie Curie intra-European fellowship (ML). AJP, GP and LE were supported by the LABEX iMUST (ANR-10-LABX-0064) of the Universite de Lyon, within the program 'Investissements d'Avenir' (ANR-11- IDEX-0007) operated by the Agence Nationale de la Recherche (ANR). JVH thanks the EPSRC and the University of Warwick for partial funding of the solid-state NMR infrastructure at Warwick, and acknowledges additional support for this infrastructure obtained through Birmingham Science City: Innovative Uses for Advanced Materials in the Modern World (West Midlands Centre for Advanced Materials Projects 1 and 2), with support from Advantage West Midlands (AWM) and partial funding by the European Regional Development Fund (ERDF).

Subjects
RECHARGEABLE LITHIUM BATTERIES, Fermi contact interaction, FUNCTIONAL THEORY, Analytical chemistry, 7. Clean energy, Molecular physics, TRANSITION-METAL PHOSPHATES, Ion, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, General Materials Science, SIDE-BAND, ADIABATIC PULSES, Spin-½, Renewable Energy, Sustainability and the Environment, Chemistry, HYPERFINE SHIFTS, Isotropy, Resolution (electron density), General Chemistry, DFT CALCULATIONS, SOLID-STATE NMR, NMR spectra database, FERMI CONTACT SHIFTS, Unpaired electron, Solid-state nuclear magnetic resonance, MAS NMR
Abstract

International audience; Olivine-type LiCoPO4 (LCP) is a high energy density lithium ion battery cathode material due to the high voltage of the Co2+/Co3+ redox reaction. However, it displays a significantly poorer electrochemical performance than its more widely investigated isostructural analogue LiFePO4 (LFP). The co-substituted LiFexCo1-xPO4 olivines combine many of the positive attributes of each end member compound and are promising next-generation cathode materials. Here, the fully lithiated x = 0, 0.25, 0.5, 0.75 and 1 samples are extensively studied using P-31 solid-state nuclear magnetic resonance (NMR). Practical approaches to broadband excitation and for the resolution of the isotropic resonances are described. First principles hybrid density functional calculations are performed on the Fermi contact shift (FCS) contributions of individual M-O-P pathways in the end members LFP and LCP and compared with the fitted values extracted from the LiFexCo1-xPO4 experimental data. Combining both data sets, the FCS for the range of local P environments expected in LiFexCo1-xPO4 have been calculated and used to assign the NMR spectra. Due to the additional unpaired electron in d(6) Fe2+ as compared with d(7) Co2+ (both high spin), LFP is expected to have larger Fermi contact shifts than LCP. However, two of the Co-O-P pathways in LCP give rise to noticeably larger shifts and the unexpected appearance of peaks outside the range delimited by the pure LFP and LCP P-31 shifts. This behaviour contrasts with that observed previously in LiFexMn1-xPO4, where all P-31 shifts lay within the LiMnPO4-LFP range. Although there are 24 distinct local P environments in LiFexCo1-xPO4, these group into seven resonances in the NMR spectra, due to significant overlap of the isotropic shifts. The local environments that give rise to the largest contributions to the spectral intensity are identified and used to simplify the assignment. This provides a tool for future studies of the electrochemically-cycled samples, which would otherwise be challenging to interpret.

Published
2014

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