Titanium Dioxide Nanoparticles Functionalized with Pd and W Complexes of a Catecholphosphane Ligand

Intrinsic hydroquinone-functionalized aggregation-induced emission core shows redox and pH sensitivity

Aggregation-induced emission (AIE) fluorophores exhibit strong fluorescence in an aggregated state but emit no or weak fluorescence in dilute solutions. This emerging class of AIE optical materials comprise a variety of functionalities. Here an AIE luminescence core, 1-hydroquinol-1,2,2-triphenylethene (HQTPE), has been designed and synthesized. This AIE core is simple but is fundamentally important to chemistry because of its intrinsic redox and pH activities. The incorporation of hydroquinone (HQ) moiety into a common AIE core tetraphenylethene (TPE) yields HQTPE with unique fluorescent properties like nonlinear self-quenching over most other AIE-active fluorophores (AIEgens) so far reported. There are differences of photochemical properties between HQTPE, 1-benzoquinol-1,2,2-triphenylethene (QTPE, the oxidized counterpart) and its anions. Interestingly, as the solution concentration is increased, AIEgen HQTPE shows stronger fluorescence but QTPE exhibits rapid quenching of fluorescence in a nonlinear fashion, which are in agreement with theoretical studies. The fluorescence of HQTPE is also highly dependent on the pH value of media. We have further explored HQTPE as an ultrasensitive redox probe and efficient deoxidizer, which could lead to potential applications in health care, food security, environmental monitoring, optic and electronic devices.

Palladium-Based Catalytic Systems for the Synthesis of Conjugated Enynes by Sonogashira Reactions and Related Alkynylations

Conjugated alkynes are recurring building blocks in natural products, a wide range of industrial intermediates, pharmaceuticals and agrochemicals, and molecular materials for optics and electronics. The palladium-catalyzed cross-coupling between sp(2)-hybridized carbon atoms of aryl, heteroaryl, and vinyl halides with sp-hybridized carbon atoms of terminal acetylenes is one of the most important developments in the field of alkyne chemistry over the past 50 years. The seminal work of the 1970s has initiated an intense search for more general and reliable reaction conditions. The interest in the catalytic activation of demanding substrates, the need to minimize the consumption of depletive resources, and the search for easy access to an increased variety of functionalized enynes has led to the current generations of high-turnover catalysts. This Review gives an overview of the highly efficient palladium catalyst systems for the direct alkynylation of C(sp(2)) halides with terminal alkynes, both in homogeneous and heterogeneous phases.

Template controlled self-assembly of bidentate phosphine complexes with hemilabile coordination behaviour

Template-assisted self-assembly of ditopic catechol phosphines creates complexes containing a chelating diphosphine ligand, which display hemilabile coordination properties with prospects for applications in catalysis.

cis-[PtBr2{PPh2(4-catechol)}2]: synthesis, crystal structure, and computational modelling of its binding to nanocrystalline TiO2

The complex cis-[PtBr(2){PPh(2)(4-catechol)}(2)]1 has been synthesized by cleavage of the four methyl groups from cis-[PtCl(2){PPh(2)(4-veratrole)}(2)] using BBr(3), followed by work-up in the presence of excess bromide. An X-ray crystal structure of 1.(ethanol)(2) confirms that the two catechol rings are adjacent to each other and approximately parallel, and therefore well structured to act as double bidentate ligands for adjacent metal atoms on the surface of a nanocrystal. The crystal packing of 1.(ethanol)(2) involves intermolecular hydrogen-bonding interactions and a parallel fourfold phenyl embrace between PPh(2) moieties. Density functional calculations have demonstrated that conformational variability of the aryl rings in cis-[PtBr(2){PPh(2)(4-catechol)}(2)] is energetically feasible, and two conformations of cis-[PtBr(2){PPh(2)(4-catechol)}(2)] as a complex ligand for Ti atoms on the various surfaces of the anatase and rutile structures of TiO(2) have been assessed for geometrical commensurability. Three structural models for adsorbates of cis-[PtBr(2){PPh(2)(4-catechol)}(2)] on TiO(2) are developed for anatase (110), anatase (101), and rutile (001).