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Chan K.-H.,HKU Shenzhen Institute of Research and Innovation | Guan X.,University of Hong Kong | Lo V.K.-Y.,HKU Shenzhen Institute of Research and Innovation | Che C.-M.,HKU Shenzhen Institute of Research and Innovation
Angewandte Chemie - International Edition | Year: 2014

Bis(NHC)ruthenium(II)-porphyrin complexes were designed, synthesized, and characterized. Owing to the strong donor strength of axial NHC ligands in stabilizing the trans Mï£CRR′/Mï£NR moiety, these complexes showed unprecedently high catalytic activity towards alkene cyclopropanation, carbene C-H, N-H, S-H, and O-H insertion, alkene aziridination, and nitrene C-H insertion with turnover frequencies up to 1950 min-1. The use of chiral [Ru(D4-Por)(BIMe)2] (1 g) as a catalyst led to highly enantioselective carbene/nitrene transfer and insertion reactions with up to 98 % ee. Carbene modification of the N terminus of peptides at 37 °C was possible. DFT calculations revealed that the trans axial NHC ligand facilitates the decomposition of diazo compounds by stabilizing the metal-carbene reaction intermediate. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Xiao X.-S.,University of Hong Kong | Lu W.,South University of Science and Technology of China | Che C.-M.,University of Hong Kong | Che C.-M.,HKU Shenzhen Institute of Research and Innovation
Chemical Science | Year: 2014

A new class of dinuclear cyclometalated platinum(ii) complexes with [PtII(C^N^N)CNR]+ (HC^N^N = 6-phenyl-2,2′-bipyridyl, CNR = 2,6-dimethylphenyl isocyanide) motifs covalently connected by oligo(oxyethylene) chains form luminescent lyotropic chromonic liquid crystals or hydrogels in aqueous dispersions with intra- and intermolecular Pt⋯Pt and π-π interactions as the driving force. Their solution behaviour is modulated by the length of the oligo(oxyethylene) chain connecting the two cyclometalated platinum(ii) motifs. One of the dinuclear Pt(ii) complexes with a long oligo(oxyethylene) bridge and which does not display intramolecular Pt⋯Pt and π-π interactions can act as an effective 'gelling stimulus' for mononuclear [PtII(C^N^N)CNR]+ complexes in aqueous solutions, resulting in the formation of a nematic hydrogel that is persistent and displays red photoluminescence. This journal is © the Partner Organisations 2014.

Lai W.-F.,University of Hong Kong | Shum H.C.,University of Hong Kong | Shum H.C.,HKU Shenzhen Institute of Research and Innovation
Nanoscale | Year: 2016

Proteins have emerged as an important class of therapeutic agents due to their high specificity in their physiological actions. Over the years, diverse protein carriers have been developed; however, some concerns, such as the relatively low loading efficiency and release sustainability, have limited the efficiency of protein delivery. This study reports the use of hydrogel nanoparticles based on a novel copolymer, poly(ethylenimine)-graft-polysorbate (PEIP), as effective protein carriers. The copolymer is fabricated by grafting poly(ethylenimine) (PEI) with polysorbate 20 using carbonyldiimidazole chemistry. Its cytotoxicity is much lower than that of unmodified PEI in RGC5 and HEK293 cells. In comparison with nanoparticles formed by unmodified PEI, our nanoparticles are not only more efficient in cellular internalization, as indicated by the 5- to 6-fold reduction in the time they take to cause 90% of cells to exhibit intracellular fluorescence, but also give a protein loading efficiency as high as 70-90%. These, together with the salt-responsiveness of the nanoparticles in protein release and the retention of the activity of the loaded protein, suggest that PEIP and its hydrogel nanoparticles warrant further development as protein carriers for therapeutic applications. © 2016 The Royal Society of Chemistry.

Lok C.-N.,University of Hong Kong | Zou T.,University of Hong Kong | Zhang J.-J.,University of Hong Kong | Lin I.W.-S.,University of Hong Kong | And 2 more authors.
Advanced Materials | Year: 2014

The therapeutic applications of many anticancer or antimicrobial metal complexes often suffer from low solubility and low stability in physiological conditions or from drug resistance. To circumvent these problems, nanoparticle systems that allow controlled release and specific accumulation in the targeted disease tissue are of advantage for efficient treatment with minimal toxicity. The focus of this Research News is metal-based nanomaterials comprising anticancer gold(III)/platinum(II) complexes or antimicrobial silver, highlighting the controlled-release properties of self-assembled metal systems. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zou T.,University of Hong Kong | Lok C.-N.,University of Hong Kong | Fung Y.M.E.,University of Hong Kong | Che C.-M.,University of Hong Kong | Che C.-M.,HKU Shenzhen Institute of Research and Innovation
Chemical Communications | Year: 2013

A panel of luminescent platinum(ii) complexes containing bidentate N-heterocyclic carbene ligands selectively localize to the endoplasmic reticulum (ER) domain, induce ER stress and cell apoptosis. Some of them show potent photo-toxicity to cancer cells. © 2013 The Royal Society of Chemistry.

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