Inorganic chemistry has evolved from fundamental studies to the forefronts of interdisciplinary research. What was considered to be impossible or elusive has now become feasible. While we still keep our identity as inorganic chemists, the sharp demarcation between the divisions of different subject disciplines or subdisciplines is no longer relevant Read more in the Editorial by Vivian W.-W. Yam.

任咏华    

Angewandte Chemie - International Edition

2015

With the involvement of transition metal centres in the gel structures, metallogels have demonstrated unique and interesting properties, which could hardly be achieved by organic compounds alone. Over the years, highly phosphorescent, catalytic, magnetic and multi-stimuli-responsive metallogels have been reported. In addition, with the incorporation of d and d metal complexes, as exemplified by Au(i), Au(iii) and Pt(ii), metal-metal interactions have also been utilized to tune the gel properties. Drastic colour and emission changes are usually observed when there is formation or disruption of metal-metal interactions during sol-gel transitions upon the introduction of external stimuli. The drastic colour or emission changes are useful to report the subtle changes in the microenvironment and the packing of the gelator molecules, thus giving valuable information for the more rational design of gelators. The recent development of metallogels involving the use of transition metals is reviewed in this chapter. The special structural, spectroscopic and stimuli-responsive behaviour of the metallogels are highlighted.

Po Charlotte    任咏华    

RSC Smart Materials

2015

任咏华     Au Vonika Ka-Man    Leung Sammual Yu-Lut   

Chemical Reviews

2015

Two series of Bodipy-containing photochromic spirooxazine and spiropyran derivatives have been designed, synthesized and characterized by H NMR, ESI mass spectrometry and elemental analysis. Their electrochemical and photochromic properties were investigated. The photophysical, ultrafast transient absorption, and fluorescence resonance energy transfer (FRET) properties from Bodipy (donor) to the ring-opened merocyanine (acceptor) were also studied. Upon photoexcitation, all the photochromic spirooxazine- and spiropyran-containing compounds exhibited reversible photochromism. Computational studies have been performed to provide further insights into the nature of the electronic transitions for the two classes of compounds. The rate constants and activation parameters for thermal bleaching reactions of compounds SO, SP-alkyne, 1-3, and 8-10 were determined through kinetic studies in acetonitrile. The thermal bleaching reaction rate of the spiropyran-containing compounds is found to be much slower than that of the spirooxazine-containing counterparts. © 2014 American Chemical Society.

Kong Lingcan    Wong Hok-Lai    Anthony yiu yan Tam    Lam Wai Han    Lixin Wu    任咏华    

ACS Applied Materials and Interfaces

2014

A number of ruthenium(II) and rhenium(I) bipyridine complexes functionalized with lipoic acid moieties have been synthesized and characterized. Functionalization of gold nanoparticles with these chromophoric ruthenium(II) and rhenium(I) complexes has resulted in interesting supramolecular assemblies with Förster resonance energy transfer (FRET) properties that could be modulated via esterase hydrolysis. The luminescence of the metal complex chromophores was turned on upon cleavage of the ester bond linkage by esterase to reduce the efficiency of FRET quenching. The prepared nanoassembly conjugates have been characterized by transmission electron microscopy (TEM), energy-dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), UV-visible spectroscopy, and emission spectroscopy. The quenching mechanism has also been studied by transient absorption and time-resolved emission decay measurements. The FRET efficiencies were found to vary with the nature of the chromophores and the length of the spacer between the donor (transition metal complexes) and the acceptor (gold nanoparticles). © 2014 American Chemical Society.

Leung Frankie Chi-Ming    Anthony yiu yan Tam    Au Vonika Ka-Man    Meijin Li    任咏华    

ACS Applied Materials and Interfaces

2014

A series of amphiphilic sulfonate-pendant platinum(ii) bzimpy complexes with different lengths of alkyl chains on the alkynyl ligands has been found to show unusual absorption and emission behavior with changes to the length of the alkyl chain. The spectroscopic changes are found to be associated with the formation of self-assembled nanostructures and through the studies of their spectroscopic properties and aggregate morphology, further insights into the relationship between the molecular structures and their molecular packing are obtained. © 2014 the Partner Organisations.

Po Charlotte    Anthony yiu yan Tam    任咏华    

Chemical Science

2014

An alkynylplatinum(II) terpyridine complex functionalized with polyhedral oligomeric silsesquioxanes (POSS) moieties has been demonstrated to exhibit self-association behavior to give various distinguishable nanostructures with interesting morphological transformation from rings to rods in response to solvent conditions through the stabilization of Pt···Pt and π-π stacking interactions as well as hydrophobic-hydrophobic interactions. These changes can be systemically controlled by varying the solvent composition and have been studied by H NMR, electron microscopy, UV-vis absorption, and emission spectroscopies.

Au-Yeung Ho-Leung    Leung Sammual Yu-Lut    Anthony yiu yan Tam    任咏华    

Journal of the American Chemical Society

2014

Metal-metal bonding interactions have been used to generate a number of unique supramolecular assemblies with fascinating functions. We presented here a new class of gold(I)-containing metallosupramolecular cages and cage-built two-dimensional (2-D) arrays of {AuL} (n = 1 or ∞, L = tetrakis-dithiocarbamato-calix[4]arene, TDCC), 1-3, which are constructed from the self-assembly of deep-cavitand calix[4]arene-based supramolecular cages consisting of octanuclear Au(I) motifs. Synchrotron radiation X-ray diffraction structural analyses of 1-3 revealed their quadruple-stranded helicate dimeric cage structure and the presence of 2-D arrays of cages linked together by inter- and intramolecular Au ···Au interactions. Electronic absorption and emission studies of complexes 1-3 indicated the occurrence of a programmable self-assembly process in a concentration-dependent stepwise manner with the links built via aurophilic interactions. These novel gold(I) supramolecular cages exhibited green phosphorescence and have been shown to serve as highly selective proof-of-concept luminescent sensors toward Ag cation among various competitive transition-metal ions. © 2014 American Chemical Society.

Jiang Xuan-Feng    Hau Franky Ka-Wah    Qingfu Sun    Yu Shu-Yan    任咏华    

Journal of the American Chemical Society

2014

Leung Sammual Yu-Lut    任咏华    

Chemical Science

2014

Unprecedented addition reaction-induced gold(I) cluster-to-cluster transformation has been observed in the present work. Reaction of the chlorogold(I) precursor, [vdpp(AuCl)] (vdpp = vinylidenebis(diphenylphosphine)) containing the diphosphine with unsaturated C=C bond, with HS resulted in a series of polynuclear gold(I) μ-sulfido clusters bearing Au(I)⋯Au(I) interactions; the identities of which have been fully characterized by NMR, electrospray-ionization mass spectrometry, elemental analysis, and single crystal X-ray diffraction analysis. Diverse research methods, including UV-vis absorption, H NMR, and P NMR spectroscopy, were employed to detect and monitor the transformation and assembly processes. Supported by single crystal structures, the existence of Au(I)⋯Au(I) bonding interactions sustains the diverse array of sophisticated polynuclear cluster structures and endues them with rich luminescence features. © 2014 American Chemical Society.

Yao Liao-Yuan    Hau Franky Ka-Wah    任咏华    

Journal of the American Chemical Society

2014