A rapidly-reversible absorptive and emissive vapochromic Pt(II) pincer-based chemical sensor.

Selective, robust and cost-effective chemical sensors for detecting small volatile-organic compounds (VOCs) have widespread applications in industry, healthcare and environmental monitoring. Here we design a Pt(II) pincer-type material with selective absorptive and emissive responses to methanol and water. The yellow anhydrous form converts reversibly on a subsecond timescale to a red hydrate in the presence of parts-per-thousand levels of atmospheric water vapour. Exposure to methanol induces a similarly-rapid and reversible colour change to a blue methanol solvate. Stable smart coatings on glass demonstrate robust switching over 104 cycles, and flexible microporous polymer membranes incorporating microcrystals of the complex show identical vapochromic behaviour. The rapid vapochromic response can be rationalised from the crystal structure, and in combination with quantum-chemical modelling, we provide a complete microscopic picture of the switching mechanism. We discuss how this multiscale design approach can be used to obtain new compounds with tailored VOC selectivity and spectral responses.

Directed Assembly Network phase three launch: a round-up of success to date and strategy for the future.

To showcase the Networks' success during phase two (2012-2016), and to set out the strategy for phase three (2017-2019), the Directed Assembly Network held a meeting at the Royal Society in London, United Kingdom on 14 and 15 December 2016. Seventy Network members from both industry and academia attended the event. The meeting, which was used as a springboard to launch and distribute the Networks' 2017 Roadmap to Innovation, comprised of invited talks, an advisory committee meeting, a panel Q & A session and networking.

Fabrication of shuttle-junctions for nanomechanical transfer of electrons.

We report on the fabrication of nanomechanical devices for shuttling of electrons from one electrode to another. Each device consists of a 20 nm diameter gold nanoparticle embedded within the gap between two gold electrodes. In two different kinds of shuttle-junctions the nanoparticle is attached to the electrodes through either (i) a single layer of 1,8-octanedithiol or (ii) a multilayer of 1-octanethiol molecules. The thiol layers play the role of 'damped springs', such that when a sufficient voltage bias is applied to the junction, the nanoparticle is expected to start oscillating and thereby transferring electrons from one electrode to the other. For both kinds of shuttle-junctions we observed an abrupt increase in the transmitted current above a threshold voltage, which can be attributed to a transition from the stationary to the oscillating regime. The threshold voltage was found to be lower for single-layer shuttle-junctions.

The energy gap law for triplet states in Pt-containing conjugated polymers and monomers.

The energy gap law established for aromatic hydrocarbons and rare earth ions relates the nonradiative decay rate to the energy gap of a transition through a multiphonon emission process. We show that this energy gap law can be applied to the phosphoresce of a series of conjugated polymers and monomers for which the radiative decay rate has been enhanced through incorporation of a heavy metal. We find that the nonradiative decay rate from the triplet state T(1) increases exponentially with decreasing T(1)-S(0) gap for the polymers and monomers at 300 and 20 K. Comparison of the nonradiative decay of polymers with that of their corresponding monomers highlights the role of electron-lattice coupling.

Analysis of two cycloplatinated compounds derived from N-(4-methoxyphenyl)-alpha-benzoylbenzylidenamine. Comparison of the activity of these compounds with other isostructural cyclopalladated compounds.

In the present paper we report the synthesis, structural characterization, biochemical properties, and antiproliferative activity of two organo-cis-platinum cyclometalated compounds of formula [M(4-OMeC6H4N=C(COC6H5)C6H4)X]2, where M = Pt and X=Cl (4) or OAc (5). The IR and 1H and 13C NMR data of the chloro-bridged compound 4 showed that it has a planar structure. As indicated by IR and 1H and 13C NMR, the acetate-bridged compound 5 has an open-book shape structure. This structure was further confirmed by X-ray diffraction. The comparison of the biochemical properties and antiproliferative activity of these compounds relative to the isostructural palladium compounds [Pd(4-OMeC6H4N=C(COC6H5)C6H4)X]2 [X = AcO (1) and (2) or Cl (3)] indicated that the activity of compounds 4 and 5 is higher than that of the corresponding isostructural compounds 3 and 1-2, respectively, since their ID50 are 2-9-fold lower. It seems that there are not differences in the antiproliferative activity of all these compounds against leukemia HL-60 cells or mammary cancer MDA-MB 468 cells. Compounds 4 and 5 modify also the DNA structure of the oc and ccc forms of plasmid DNA. The acetate-bridged compound 5 showed the highest antiproliferative activity which is even higher than that of cis-DPP. Our data indicate that the Pt(II) compounds are more active than those having Pd(II) as the metal center.