We report a 2D layered metal-organic framework (MOF) with wide channels named NUS-1 and its activated analogue NUS-1a composed of Zn4O-like secondary building units and tetraphenylethene (TPE)-based ligand 4,4'-(2,2-diphenylethene-1,1-diyl)dibenzoic acid. Due to its special structure, NUS-1a exhibits unprecedented gas sorption behavior, glass-transition-like phase transition under cryogenic conditions, and responsive turn-on fluorescence to various volatile organic compounds. Our approach using angular ligand containing partially fixed TPE units paves a way toward highly porous MOFs with fluorescence turn-on response that will find wide applications in chemical sensing.

period of irradiation, and that the Ag particles display irregular shapes. Increasing the concentration of PVA in the system is found to be favorable for the formation of the shaped Ag particles. This result of the influence of the concentration of PVA on the shape of the Ag nanoparticles is very similar to that obtained by El-Sayed and co-workers, [19] who reported that the ratio of the concentration of the capping polymer material to the concentration of the platinum cations can influence the shapes and sizes of platinum nanoparticles. In the present study, the protecting agent PVA may also be a kind of capping polymer material, which usually acts as a molecularly dissolved surface modifier or steric stabilizer. Its presence in the system plays an important role in the formation of the Ag nanostructures. However, the mechanism of the shape-or morphology-dependent synthesis of colloidal nanoparticles is not yet known and needs to be investigated further.In summary, single-crystal Ag nanorods and elegant, highly ordered dendritic supramolecular nanostructures of Ag nanoparticles have been prepared via a novel ultraviolet irradiation photoreduction technique at room temperature using PVA as a protecting agent. It was found that the concentrations of both AgNO 3 and PVA play a significant role in the formation and growth of the Ag nanorods and dendrites. These Ag nanoparticles with unusual nanostructures may have important applications in catalysis. This method may be extended to prepare novel nanostructures of other noble metals.Many luminescent organic and polymer materials have been used for the fabrication of light-emitting diodes (LEDs). [1±3] Generally, electroluminescence (EL) was considered to originate from the singlet excited state [4] because for the majority of organic molecules, the triplet excited state exhibits a low emission quantum yield, thus does not contribute to EL emission. In EL, the existence of a bound triplet excited state can severely limit the quantum efficiency. If the triplet binding energy and corresponding cross section for forming a triplet from a pair of injected Fig. 3. The TEM image of the product obtained by irradiating the solution containing 3 wt.-% PVA and 10 ±2 M AgNO 3 .

A family of mono- and binuclear Cy(3)P-supported gold(I) complexes containing various pi-conjugated linear arylacetylide ligands, including the two homologous series (Cy(3)P)Au(Ctbd1;CC(6)H(4))(n)()(-)(1)(Ctbd1;CPh) and (Cy(3)P)Au(Ctbd1;CC(6)H(4))(n)()Ctbd1;CAu(PCy(3)) (n = 1-4), have been prepared. X-ray crystal analyses revealed no intermolecular aurophilic interactions in their crystal lattice. The lowest-energy singlet transitions are predominately intraligand in nature and exhibit both phenyl and acetylenic (1)(pipi) character. Strong photoluminescence is detected in solid and solution states under ambient conditions, with lifetimes in the microsecond regime. For complexes with a single arylacetylide group, only phosphorescence from the arylacetylide (3)(pipi) state is observed. Vibrational spacings in the solid-state emission spectra can be attributed to a combination of phenyl ring deformation and symmetric phenyl ring and Ctbd1;C stretches. Additional delayed-fluorescence emission is recorded for complexes with multiple p-arylacetylide units, and this is attributed to a triplet-triplet annihilation process. The phosphorescence energy of these complexes are readily modified by altering the length of the conjugated arylacetylide system, while the intensity of phosphorescence relative to fluorescence decreases when the p-arylacetylide chain is elongated. Information regarding the nature and relative energies of arylacetylide singlet and triplet excited states has been derived from the two homologous series and extrapolated to polymeric arylacetylide species. The (3)(pipi) excited-state reduction potentials E degrees [Au(+)/Au] (Au = 1a, 2, and 4) are estimated to be -1.80, -1.28, and -1.17 V versus SSCE, respectively.

The synthesis and X-ray structural and spectroscopic characterization for LAuC triple bond CAuL x 4CHCl(3) and LAuC triple bond C--C triple bond CAuL x 2CH(2)Cl(2) (1 x 4CHCl(3) and 2 x 2CH(2)Cl(2), respectively; L = PCy(3), tricyclohexylphosphine) are reported. The bridging C(n)(2-) units are structurally characterized as acetylene or diacetylene units, with C triple bond C distances of 1.19(1) and 1.199(8) A for 1 x 4CHCl(3) and 2 x 2CH(2)Cl(2), respectively. An important consequence of bonding to Au(I) for the C(n)(2-) moieties is that the lowest-energy electronic excited states, which are essentially acetylenic (3)(pi pi*) in nature, acquire sufficient allowedness via Au spin-orbit coupling to appear prominently in both electronic absorption and emission spectra. The origin lines for both complexes are well-defined and are observed at 331 and 413 nm for 1 and 2, respectively. Sharp vibronic progressions corresponding to v(C triple bond C) are observed in both emission and absorption spectra. The acetylenic (3)(pi pi) excited state of 2 has a long lifetime (tau(0) = 10.8 mus) in dichloromethane at room temperature and is a powerful reductant (E degrees [Au(2)(+)/Au(2)] < or = -1.85 V vs SSCE).

Reaction of polymeric gold(I) acetylide species (bpyC[triple bond]CAu)n (bpyC[triple bond]CH = 5-ethynyl-2,2'-bipyridine) with diphosphine ligands Ph2P(CH2)nPPh2 (n = 2-6) or 1,1'-bis(diphenylphosphino)-ferrocene (dppf) in dichloromethane induces isolation of binuclear gold(I) complexes (bpyC[triple bond]CAu)2{mu-Ph2P(CH2)nPPh2} or (bpyC[triple bond]CAu)2(mu-dppf). Complexation of Ln(hfac)3 (hfac = hexafluoroacetylacetonate, Ln = Nd, Eu, Er, Yb) subunits to the binuclear gold(I) complexes through 2,2'-bipyridyl chelation gives the corresponding Au4Ln4 or Au2Ln2 heteropolynuclear complexes. Noticeably, upon formation of the Au4Ln4 arrays by complexation of (bpyC[triple bond]CAu)2(mu-Ph2P(CH2)4PPh2) (3) with Ln(hfac)3 units, trans-conformation in 3 transforms dramatically to the cis-arranged form due to the strong driving force from ligand-unsupported Au-Au contacts between two Au2Ln2 subunits. In contrast, cis-conformation in (bpyC[triple bond]CAu)2(mu-dppf) (6) stabilized by Au-Au interactions is reversed to the trans-oriented form upon formation of Au2Ln2 arrays by introducing Ln(hfac)3 units through 2,2-bipyridyl chelation. The binuclear gold(I) complexes show bright blue luminescence featured by ligand-centered pi --> pi* (C[triple bond]Cbpy) states together with low-energy emission at 500-540 nm, associated with 3(pi-->pi*) excited states, mixed probably with some characteristic from (Au-Au) --> (C[triple bond]Cbpy) 3MMLCT transition. For Au4Ln4 or Au2Ln2 complexes, sensitized lanthanide luminescence is achieved by energy transfer from Au-acetylide chromophores with lifetimes in the sub-millisecond range for EuIII complexes, whereas in the microsecond range for near-infrared emitting NdIII, ErIII, and YbIII species.