A series of cis-dioxorhenium(V) complexes containing chiral tetradentate N ligands, including cis-[Re(O)(pyxn)] (1; pyxn = N,N′-dimethyl-N,N′-bis(2-pyridylmethyl)cyclohexane-1,2-diamine), cis-[Re(O)(6-Mepyxn)] (cis-2), cis-[Re(O)(R,R-pdp)] (3; R,R-pdp = 1,1′-bis((R,R)-2-pyridinylmethyl)-2,2′-bipyrrolidine), cis-[Re(O)(R,R-6-Mepdp)] (4), and cis-[Re(O)(bqcn)] (5; bqcn = N,N′-dimethyl-N,N′-di(quinolin-8-yl)cyclohexane-1,2-diamine), were synthesized. Their structures were established by X-ray crystallography, showing Re-O distances in the range of 1.740(3)-1.769(8) Å and O-Re-O angles of 121.4(2)-124.8(4)°. Their cyclic voltammograms in MeCN (0.1 M [NBu]PF) display a reversible Re couple at E = 0.39-0.49 V vs SCE. In aqueous media, three proton-coupled electron transfer reactions corresponding to Re, Re, and Re couples were observed at pH 1. The Pourbaix diagrams of 1·OTf, 3·OTf, and 5·OTf have been examined. The electronic absorption spectra of the cis-dioxorhenium(V) complexes show three absorption bands at around 800 nm (600-1730 dm mol cm), 580 nm (1700-5580 dm mol cm), and 462-523 nm (3170-6000 dm mol cm). Reaction of 1 with Lewis acids (or protic acids) gave cis-[Re(O)(OH)(pyxn)] (1·H), in which the Re-O distances are lengthened to 1.788(5) Å. Complex cis-2 resulted from isomerization of trans-2 at elevated temperature. cis-[Re(O)(pyxn)](PF) (1′·(PF)) was obtained by constant-potential electrolysis of 1·PF in MeCN (0.1 M [NBu]PF) at 0.56 V vs SCE; it displays shorter Re-O distances (1.722(4), 1.726(4) Å) and a smaller O-Re-O angle (114.88(18)°) relative to 1 and shows a d-d transition absorption band at 591 nm (ϵ = 77 dm mol cm). With a driving force of ca. 75 kcal mol, 1′ oxidizes hydrocarbons with weak C-H bonds (75.5-76.3 kcal mol) via hydrogen atom abstraction. DFT and TDDFT calculations on the electronic structures and spectroscopic properties of the cis-dioxorhenium(V/VI) complexes were performed.

Ng Vicky Yin Ming    Tse Chun-Wai    Xiangguo Guan    Chang Xiaoyong    Yang Chen    Low Kam-Hung    Hung kay Lee    Jie sheng Huang    支志明    

Inorganic Chemistry

2017

Gold alkynyl complexes with phosphane ligands of the type (alkynyl)Au(I)(phosphane) represent a group of bioorganometallics, which has only recently been evaluated biologically in more detail. Structure-activity-relationship studies regarding the residues of the phosphane ligand (P(Ph), P(2-furyl), P(DAPTA), P(PTA), P(Et), P(Me)) of complexes with an 4-ethynylanisole alkyne ligand revealed no strong differences concerning cytotoxicity. However, a relevant preference for the heteroatom free alkyl/aryl residues concerning inhibition of the target enzyme thioredoxin reductase was evident. Complex 1 with the triphenylphosphane ligand was selected for further studies, in which clear effects on cell morphology were monitored by time-lapse microscopy. Effects on cellular signaling were determined by ELISA microarrays and showed a significant induction of the phosphorylation of ERK1 (extracellular signal related kinase 1), ERK2 and HSP27 (heat shock protein 27) in HT-29 cells. Application of 1 in-vivo in a mouse xenograft model was found to be challenging due to the low solubility of the complex and required a formulation strategy based on a peanut oil nanoemulsion.

Andermark Vincent    Göke Katrin    Kokoschka Malte    Abu El Maaty Mohamed A.    Ching Tung Lum    Taotao Zou    Sun Raymond Wai-Yin    Aguiló Elisabet    Oehninger Luciano    Rodríguez Laura    Heike Bunjes    Stefan Wölfl    支志明     Ingo Ott   

Journal of Inorganic Biochemistry

2016

A series of phosphorescent Au(i) bis(N-heterocyclic allenylidene) complexes, namely [Au(=C=C=CRR)]X, were synthesized and structurally characterized. These organometallic complexes exhibit panchromatic transient absorption upon electronic photo-excitation and can self-organize into lyotropic chromonic mesophases in aqueous solutions.

Xiao Xin-Shan    Zou Chao    Xiangguo Guan    Yang Chen    Wei Lu    支志明    

Chemical Communications

2016

A protocol on chemoselective cobalt(II) porphyrin-catalyzed intramolecular cyclopropanation of N-alkyl indoles/pyrroles with alkylcarbenes has been developed. The reaction enables the rapid construction of a range of nitrogen-containing polycyclic compounds in moderate to high yields from readily accessible materials. These N-containing polycyclic compounds can be converted into a variety of N-heterocycles with potential synthetic and biological interest. Compared to their N-tosylhydrazone counterparts, the use of bulky N-2,4,6-triisopropylbenzenesulfonyl hydrazones as carbene precursors allows cyclopropanation to occur under milder reaction conditions.

Reddy Annapureddy Rajasekar    Hao Fei    Wu Kai    Congying Zhou    支志明    

Angewandte Chemie - International Edition

2016

Copper(I) alkynyl complexes have attracted tremendous attention in structural studies, as luminescent materials, and in catalysis, and homoleptic complexes have been reported to form polymers or large clusters. Herein, six unprecedented structures of Cualkynyl complexes and a procedure to measure the cone angles of alkynyl ligands based on the crystal structures of these complexes are reported. An increase of the alkynyl cone angle in the complexes leads to a modulation of the structures from polymeric [((PhC≡CC≡C)Cu)(NH)], to a large cluster [(TripC≡CC≡C)Cu](MeCN), to a relatively small cluster [(TripC≡C)Cu](Trip=2,4,6-iPr-CH). The complexes exhibit yellow-to-red phosphorescence at ambient temperature in the solid state and the luminescence behavior of the Cucluster is sensitive to acetonitrile.

Chang Xiaoyong    Low Kam-Hung    Wang Juan-Yu    Jie sheng Huang    支志明    

Angewandte Chemie - International Edition

2016

Here we describe the synthesis and X-ray crystal structures of a panel of cis-[Co(N)Cl] complexes (N = tetradentate N atom donor ligand). We also examine the catalytic activities of these complexes in the photochemical and electrochemical reduction of CO to CO using [Ir(ppy)] as the photosensitizer. Among the complexes studied, cis-[Co(PDP)Cl] (C1) (PDP = 1,1′-bis(2-pyridinylmethyl)-2,2′-bipyrrolidine) displayed the highest catalytic activity. This Co(ii) complex was able to effectively mediate the reduction of CO to CO under either electrochemical or visible light photocatalytic conditions. For the electrocatalysis, C1 catalysed CO to CO with up to 96% Faraday efficiency at -1.70 V (vs. SCE, SCE = saturated calomel electrode). A selectivity of up to 95% for CO production was achieved in a photocatalytic CO reduction system by using C1 as the catalyst, Ir(ppy) as the photosensitizer and triethylamine as the electron donor. The Co(i) species in situ generated by the one electron reduction of cis-[Co(PDP)Cl] is suggested to be directly responsible for CO activation. Ultrafast time (ns) resolved absorption spectroscopy revealed that the photoinduced electron transfer from the triplet excited state of Ir(ppy) to C1 is a key step in the generation of active Co(i) species. The electronic structure and redox properties of the Co(i) species, [Co(N)Cl], as well as its role in the catalytic reaction were investigated by DFT calculations. The presence of one chloride ligand cis to the CO coordination site neutralizes the positive charge on the Co(i) centre, therefore assisting the bound CO molecule in attracting protons. The reaction mechanism for CO reduction to CO catalysed by the recently reported [Co(TPA)Cl] (TPA = tris(2-pyridylmethyl)amine) catalyst was also computed. Subtle modifications of the chelating N ligand from cis-[Co(N)Cl] were found to have a profound effect on the efficiency of CO reduction by DFT calculations.

Wang Feng    Bei Cao    Wai pong To    Tse Chun-Wai    Li Kai    Chang Xiaoyong    Zang Chao    Sharon lai fung Chan    支志明    

Catalysis Science and Technology

2016

Terephthalate (CHO ) moiety with stable oxidized and reduced states is widely employed as the organic anode in batteries. However, along with the dissolution problem, the representative lithium terephthalate (LiTP) exhibited unsatisfactory cyclic and rate capability. Herein, based on the calculated and experimental results, we demonstrated that potassium terephthalate (KTP) possesses superior cyclic and rate capability in Li-ion batteries. On one hand, due to the larger radius of K ion, KTP exhibits more stable lattice architecture than LiTP for the better size matching between cations and anions; On the other hand, K ion in KTP could remain electrochemical inertness even its standard redox potential (−2.931 V) is higher than Li ion (−3.040 V). Meanwhile, the K[sbnd]O bond in KTP is calculated to be more ionic while the Li[sbnd]O bond in LiTP has more covalent character. The ionic K[sbnd]O bond of KTP could further enhance its dissolution resistance against non-polar electrolyte. Indeed, after its electronic conductivity and particle dispersity were improved by mixing with graphene, the modified KTP anode could exhibit very stable capacity of ∼122 mAh g at 8C for 500 cycles, which is comparable or even superior to the state-of-the-art Li-ion batteries currently reported for small organic molecules.

Qijiu Deng    Cong Fan    Liping Wang    Bei Cao    Jin Yingdi    支志明     Jingze Li   

Electrochimica Acta

2016

Four heteroleptic copper(I) complexes containing phenanthroline and monoanionic nido-carborane-diphosphine ligands have been prepared and structurally characterized by various spectroscopic techniques and X-ray diffraction. These complexes exhibit intense absorptions in the visible range and excited-state lifetimes on the microsecond scale. Their application in visible-light-induced cross-dehydrogenative coupling reactions was investigated. Preliminary studies showed that one of the four copper(I) complexes is an efficient catalyst for photoinduced oxidative C-H functionalization using oxygen as oxidant. Furthermore, α-functionalized tertiary amines were obtained in good-to-excellent yields by light irradiation (λ > 420 nm) of a mixture of our Cu complex, tertiary amines, and a variety of nucleophiles (nitroalkane, acetone, or indoles) under aerobic conditions. Electron paramagnetic resonance measurements provided evidence for the formation of superoxide radical anions O) rather than singlet oxygen (O) during these photocatalytic reactions.

Bin Wang    Shelar Deepak Prakash    Han Xian-Zhu    Tingting Li    Xiangguo Guan    陆卫    Liu Kun    Chen Yong    Wenfu Fu    支志明    

Chemistry - A European Journal

2015

Self-assembled functional nanoarchitectures are employed as important nanoscale building blocks for advanced materials and smart miniature devices to fulfi ll the increasing needs of high materials usage effi ciency, low energy consumption, and high-performance devices. One-dimensional (1D) crystalline nanostructures, especially molecule-composed crystalline nanostructures, attract signifi cant attention due to their fascinating infusion structure and functionality which enables the easy tailoring of organic molecules with excellent carrier mobility and crystal stability. In this review, we discuss the recent progress of 1D crystalline self-assembled nanostructures of functional molecules, which include both a small molecule-derived and a polymer-based crystalline nanostructure. The basic principles of the molecular structure design and the process engineering of 1D crystalline nanostructures are also discussed. The molecular building blocks, self-assembly structures, and their applications in optical, electrical, and photoelectrical devices are overviewed and we give a brief outlook on crucial issues that need to be addressed in future research endeavors.

Yanbing Guo    Liang Xu-    Huibiao Liu    Yongjun Li    支志明     李玉良   

Advanced Materials

2015

Abstract Organometallic platinum(II) terpyridine complexes with a caffeine derived N-heterocyclic carbene (NHC) ligand were investigated as possible anti-cancer drugs in comparison to analogs, which contain N-coordinated theobromine. In general the carbene complexes displayed significantly higher biological activity than the theobromine analogs. In particular, the caffeine derived organometallic platinum(II) complex [Pt(2,2′:6′,2″-terpyridine) (1,3,7,9-tetramethylxanthine-8-ylidene)](PF) (1) displayed very promising cytotoxic activity towards several cancer cell lines, and showed in-vitro anti-angiogenic effects at sub-cytotoxic concentrations. Moreover, it induced neural differentiation-like morphological changes in breast adenocarcinoma (MCF-7) cells.

Zhang Jing-Jing    支志明     Ingo Ott   

Journal of Organometallic Chemistry

2015