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Three pargyline-phosphine copper(I) clusters, [Cu 4 (CC-C 9 H 12 N) 3 (PPh 3 ) 4 ](PF 6 ) (1) and [Cu 6 (CC-C 9 H 12 N) 4 (dppy) 4 ](X) 2 (dppy = diphenyl-2-pyridylphosphine; X = PF 6 for 2 and X = ClO 4 for 3), were synthesized. Their structures were fully characterized using various spectroscopic methods and X-ray crystallography, which showed that the stoichiometry and nature of pargyline and phosphine ligands play an important role in tuning the structure and photophysical features of Cu(I) clusters. Interestingly, clusters 1, 2 and 3 exhibited red, orange and yellow phosphorescence with high quantum yields of 88.5%, 22.0% and 40.2%, respectively, at room temperature. Moreover, clusters 1-3 show distinct temperature-dependent emissions. The excellent luminescence performance of 1 and 3 was designed and employed for the construction of monochrome and white light-emitting devices (LEDs).

Developing low-cost and highly efficient electrocatalysts for the hydrogen evolution reaction (HER) has stimulated extensive interest. Molybdenum carbide materials have been proposed as promising alternatives to noble platinum-based catalysts due to their earth abundance and tunable physicochemical characteristics. Here, we report Mo 2 C@NC/Mo 2 C hollow microspheres composed of a β-Mo 2 C core and small β-Mo 2 C particles embedded within a nitrogen-doped carbon shell and prepared using guanosine and hexaammonium molybdate as precursors via a hydrothermal self-assembly process, which results in outstanding catalytic activity and fast kinetics in hydrogen evolution in both acidic and alkaline solutions. The significant activity improvement of Mo 2 C@NC/Mo 2 C can be attributed to the large ratio of exposed active sites and abundant interfacial structures. This work provides a new template-free strategy for the design of a highly active Mo 2 C@NC/Mo 2 C hollow microsphere HER catalyst.

A series of dinuclear platinum(ii) alkynyl complexes [Pt2L2(C[triple bond, length as m-dash]CC6H4R-4)4] (R = H 1, CH32, But3) and unusual tetranuclear Pt(ii)-Ag(i) clusters [Pt2Ag2L(C[triple bond, length as m-dash]CC6H4R-4)6] (R = H, 4; CH3, 5; But, 6), together with novel polymer crystals [Pt2Ag2L(C[triple bond, length as m-dash]CC6H5)6]∞ ([4]∞), were synthesized by a self-assembly reaction between [NBu4]2[Pt(C[triple bond, length as m-dash]CC6H4-R-4)4] and [Ag6L6]6+ (L = 4-(3,5-(diphenylphosphine)phenyl)pyridine). These complexes were characterized by using a range of spectroscopic techniques and complexes 1, 3, 5, and [4]∞ were analysed by X-ray crystallography. Each platinum atom of the Pt(ii)-Ag(i) clusters shows an unusual asymmetric distorted square planar geometry with three alkynyl groups and one bridging L phosphorus atom. Dinuclear complexes 1-3 demonstrate solid-state weak blue luminescence, while tetranuclear Pt(ii)-Ag(i) clusters 4-6 show intense blue-green or yellow-green emission. Furthermore, the crystalline samples of polymer [4]∞ display bright yellow emission (518 nm) that is significantly red-shifted as compared to monomer crystal 4.

Two windmill-like Ag3Cu5 alkynyl clusters were synthesized and characterized. They display novel PL and ECL properties, which could be modified by changing the substituent on the alkynyl ligands. According to the study of electrochemical behaviours, ECL behaviours and ECL emission spectra of the Ag3Cu5 clusters, a possible ECL mechanism was proposed.

Two novel luminescent hetero-trinuclear complexes [Pt2Ag(μ-dpppy)2(C≡CC6H4R-4)4](ClO4) (R = H, 1; R = CH3, 2; dpppy = 2,6-bis(diphenylphosphino)pyridine) were synthesized by the self-assembly reaction between [Pt(C[triple bond, length as m-dash]CC6H4R-4)4](2-) and [Ag2(μ-dpppy)3](2+) and characterized by elemental analyses, electrospray ionization mass spectrometry, and (1)H NMR and (31)P{(1)H} NMR spectroscopy and by X-ray crystallography for complex 2. Two Pt2Ag complexes show strong luminescence in the solid state, but exhibit weak emission in CH2Cl2 solution and in acetonitrile-water (1 : 1, v : v) solution at room temperature. To overcome the limitations of low water solubility and weak emission in solutions, a new kind of luminescent Pt2Ag@SiO2 nanoparticles was prepared by incorporating the new Pt2Ag acetylides into monodisperse silica nanoparticles. It is noted that Pt2Ag@SiO2 nanoparticles exhibit strong luminescence in aqueous solution, and cyanide anions tend to decrease their luminescence intensity in NaHCO3-NaOH buffer solution. Based on this, a novel nanosensor for highly sensitive detection of cyanide anions was developed in the range of 0.1-10.0 μM.

Two water soluble Re(I) tricarbonyl diimine complexes containing cationic 2,2'-bipyridyl ligands [Re(L1)(CO)(3)(AN)](2+) (1) and [Re(L2)(CO)(3)(AN)](3+) (2) (L1 and L2: a cationic 2,2'-bipyridyl ligand, AN: acetonitrile) were synthesized and characterized. Their photophysical, electrochemical and electrochemiluminescent properties were investigated. The crystal structures of the two complexes have also been determined. Electrochemiluminescence (ECL) of the two complexes 1 and 2 have been studied in aqueous buffer solution in the presence of co-reactant tri-n-propylamine (TPrA) or 2-(dibutylamino)ethanol (DBAE) at a Au working electrode. The ECL behavior of the complexes was also studied in the presence of several surfactants such as Triton X-100 and Zonyl FSN. The ECL signals of the rhenium(I) complex were enhanced about 190-fold and 70-fold at a Au electrode in the presence of Triton X-100 for the [Re(L1)(CO)(3)(AN)](2+)/TPrA and [Re(L1)(CO)(3)(AN)](2+)/DBAE systems, respectively.

A series of dinuclear compounds of [Ru(bpy)(2)(tpphz)Ln(TTA)(3)](PF(6))(2) (tpphz = tetrapyrido[3,2-a:2',3'-c:3'',2''-h:3''',4'''-j]phenazine; Ln = Er(III), Nd(III), Yb(III) and Gd(III); TTA = 2-thenoyltrifluoroacetone) have been prepared by attachment of a [Ln(TTA)(3)] fragment at the vacant diimine site of the luminescent mononuclear complex [Ru(bpy)(2)(tpphz)](PF(6))(2). In the solid state, in CH(2)Cl(2) solution and in Tris-HCl buffer solution of these dinuclear complexes Ru-Ln, sensitized near-infrared (NIR) luminescence is observed from Nd and Yb centres following excitation of the d-block unit, which results from the effective Ru → Ln (Ln = Nd, Yb) energy transfer, but no Er-based NIR luminescence is produced. The (3)MLCT (MLCT = metal to ligand charge transfer) emission is partly quenched in the Ru-Nd complex, slightly increased in the Ru-Yb complex, and is not changed in the Ru-Ercomplex. Interestingly, alpha-fetal protein (AFP) tends to decrease the NIR luminescence intensity of the Ru-Nd complex in Tris-HCl buffer solution. A novel NIR luminescent method for the determination of AFP was developed with a linear range of 0.5-18 ng mL(-1), and a detection limit of 0.2 ng mL(-1) based on 3 times the ratio of the signal-to-noise. Considering the attractive features, such as good selectivity, stability and rapidity, the proposed NIR luminescent method provides promising potential for AFP detection in clinical diagnosis and biomedical applications.

Mononuclear ruthenium complex 1 and dinuclear complex 2 were synthesized by reaction of the appropriate bidentate pyrazolyl-pyridyl-based ligand L (L = 1,4-bis(3-(2-pyridyl)pyrazol-1-ylmethyl)benzene) with cis-Ru(bipy)(2)Cl(2)·2H(2)O. They were characterized by elemental analyses, ESI-MS, (1)H spectroscopy, and X-ray crystallography for 2. Compounds 1 and 2 both emit strongly in solid states and in solutions at 298 K with the lifetimes in the microsecond range. Electrogenerated chemiluminescence (ECL) of complexes 1 and 2 in the absence or presence of coreactant tri-n-propylamine (TPrA) or 2-(dibutylamino)ethanol (DBAE) at different working electrodes in acetonitrile and phosphate buffer solutions (PBS, pH 7.5) was studied. The ECL spectra are identical to the photoluminescence spectra, indicating that the ECL emissions are due to the metal to ligand charge transfer (MLCT). In all cases, ECL quantum efficiencies of dinuclear complex 2 are higher than those of mononuclear complex 1, and ECL quantum efficiencies of complexes 1 and 2/TPrA system are higher than those of DBAE system. It is noted that diuretic furosemide tends to decrease the ECL intensity of complex 2/TPrA system in PBS (pH 7.5) at GC working electrode. A novel ECL method for the determination of diuretic furosemide was developed with a linear range between 2.0 × 10(-7) mol L(-1) and 1.0 × 10(-6) mol L(-1), and a detection limit of 1.2 × 10(-8) mol L(-1) based on 3 times the ratio of signal-to-noise., (This journal is © The Royal Society of Chemistry 2011)

Three rhenium carbonyl complexes 1-3 were synthesized by reaction of the appropriate bidentate pyrazolyl-pyridyl-based ligand L1, L2 (L1 = 2-[1-{4-(bromomethyl)benzyl}-1H-pyrazol-3-yl]pyridine; L2 = 1,4-bis(3-(2-pyridyl)pyrazol-1-ylmethyl)benzene) with [Re(CO)(5)Cl] in toluene. They were characterized by elemental analyses, ESI-MS, (1)H spectroscopy, and X-ray crystallography for 1 and 2. Compounds 1-3 exhibit bright yellow-green luminescence in the solid state and in solution at 298 K with the lifetimes in the microsecond range. It is noteworthy that the luminescent quantum efficiencies of compounds 1-3 are between 0.040 and 0.051, which are much higher than that of the [Re(bpy)(CO)(3)Cl] complex (= 0.019) (M. M. Richter et al., Anal. Chem., 1996, 68, 4370; J. Van Houten et al., J. Am. Chem. Soc., 1976, 98, 4853). Electrogenerated chemiluminescence (ECL) was observed in solutions of these complexes in the absence or presence of coreactant tri-n-propylamine (TPrA) or 2-(dibutylamino)ethanol (DBAE) by stepping the potential of a Pt disk working electrode. The ECL spectra are identical to the photoluminescence spectra, indicating that the chemical reactions following electrochemical oxidation or reduction form the same (3)MLCT excited states as that generated in the photoluminescence experiments. In most cases, the ECL quantum efficiencies of complexes 1-3 are comparable to that of the [Re(L)(CO)(3)Cl] (L = bpy or phen) system. Oxygen tends to substantially decrease ECL intensities of the three rhenium complexes-TPrA system, which could allow them to be used as oxygen sensors.