Gold(I)-Thiolate Coordination Polymers as Multifunctional Materials: The Case of Au(I)-p-Fluorothiophenolate.

Gold-sulfur interaction has vital importance in nanotechnologies and material chemistry to design functional nanoparticles, self-assembled monolayers, or molecular complexes. In this paper, a mixture of only two basic precursors, such as the chloroauric acid (HAu(III)Cl4) and a thiol molecule (p-fluorothiophenol (p-HSPhF)), are used for the synthesis of gold(I)-thiolate coordination polymers. Under different conditions of synthesis and external stimuli, five different functional materials with different states of [Au(I)(p-SPhF)]n can be afforded. These gold-thiolate compounds are (i) red emissive, flexible, and crystalline fibers; (ii) composite materials made of these red emissive fibers and gold nanoparticles; (iii) amorphous phase; (iv) transparent glass; and (v) amorphous-to-crystalline phase-change material associated with an ON/OFF switch of luminescence. The different functionalities of these materials highlight the great versatility of the gold(I) thiolate coordination polymers with easy synthesis and diverse shaping that may have great potential as sustainable phosphors, smart textiles, sensors, and phase change memories.

Porphyrin-Based MOF Thin Film on Transparent Conducting Oxide: Investigation of Growth, Porosity and Photoelectrochemical Properties.

Synthesizing metal-organic frameworks (MOFs) composites with a controlled morphology is an important requirement to access materials of desired patterning and composition. Since the last decade, MOF growth from sacrificial metal oxide layer is increasingly developed as it represents an efficient pathway to functionalize a large number of substrates. In this study, porphyrin-based Al-PMOF thin films were grown on conductive transparent oxide substrates from sacrificial layers of ALD-deposited alumina oxide. The control of the solvent composition and the number of atomic layer deposition (ALD) cycles allow us to tune the crystallinity, morphology and thickness of the produced thin films. Photophysical studies evidence that Al-PMOF thin films present light absorption and emission properties governed by the porphyrinic linker, without any quenching upon increasing the film thickness. Al-PMOF thin films obtained through this methodology present a remarkably high optical quality both in terms of transparency and coverage. The porosity of the samples is demonstrated by ellipsometry and used for Zn(II) insertion inside the MOF thin film. The multifunctional transparent, porous and luminescent thin film grown on fluorine-doped tin oxide (FTO) is used as an electrode capable of photoinduced charge separation upon simulated sunlight irradiation.

Tuning the 1D-2D dimensionality upon ligand exchange in silver thiolate coordination polymers with photoemission switching.

Silver nanoparticles are known and widely used for their antimicrobial activities. Nevertheless, once they are released into the natural or biological environments, they can become toxic with time, because of the dissolution of some Ag(I) ions that can then react with thiol-based molecules, such as glutathione and/or compete with copper proteins. These assumptions are based on the high affinity of the soft acid Ag(I) and the soft base thiolates and the exchange reactions that are involved in complex physiological media. Here we synthesized and fully characterized two new 2D silver thiolate coordination polymers (CPs) that exhibit a reversible 2D-to-1D structural transformation in the presence of an excess of thiol molecules. This dimensionality change induces also a switch of the yellow emission of the Ag-thiolate CP. This study highlights that these highly stable silver-thiolate CPs, in basic, acidic and oxidant media can undergo a complete dissolution-recrystallization mechanism upon thiol exchange reactions.

Luminescent and sustainable d10 coinage metal thiolate coordination polymers for high-temperature optical sensing.

The d10 coinage metal coordination polymers (CPs) are known to display photophysical properties which can be tuned depending on the functionality of the ligand. Three new CPs made of d10 coinage metals and methyl thiosalicylate, [M(o-SPhCO2Me)]n (M = Cu, Ag, Au), are reported. They are all constructed from one-dimensional metal-sulfur networks, in which Cu and Ag are three-coordinated to sulfur atoms, whereas Au is only two-coordinated. It results that both Cu(I) and Ag(I) CPs show orange photoemission at room temperature, and the Au(I) one exhibits near-infrared emission at low temperatures. The intense orange-emissive Ag(I) CP and the blue-emissive coumarin 120 have been mixed in an organic matrix, the polyvinylidene fluoride (PVDF), to form a dual luminescent flexible composite film. This film, evaluated for thermometry, shows great sensitivity for temperatures up to 100°C, a temperature never reached with non-lanthanide-based CPs.

A chiral 3D silver(I)-benzenedithiolate coordination polymer exhibiting photoemission and non-linear optical response.

A new tridimensional metal-organic chalcogenolate, made of a 1,3-benzenedithiolate bridging ligand and Ag(I), [Ag2(1,3-BDT)]n, is reported. This coordination polymer has good thermal stability in air and displays both photoluminescence properties and a second harmonic generation response.