Search

New thermosensitive liposomes with a phase transition at 42 °C, containing nickel–bis(dithiolene) complexes as efficient and stable photothermal agents, have been formulated and characterized. These liposomes are highly stable and keep their contents at 37 °C for more than 30 days. On the contrary, the mild hyperthermia generated by the nickel–bis(dithiolene) complex under 940 nm NIR irradiation allows for the fine controlled release of the liposome contents, making such liposomes highly suitable for on-demand drug delivery in the human body under NIR laser irradiation. These liposomes can also be directly used, as shown here, as nanoagents for photothermal therapy. In fact, strong cell death can be generated under laser irradiation in the presence of these photothermally active nanocargos containing less than 10% w/w of metal complex. We also demonstrate, for the first time, that nickel–bis(dithiolene) complexes are good photoacoustic agents, generating easily detectable ultrasonic signals directly proportional to the concentration of complexes and the used laser power.

While the introduction of large, bulky substituents such as tert-butyl, −SiMe3, or −Si(isopropyl)3has been used recently to control the solid state structures and charge mobility of organic semiconductors, this crystal engineering strategy is usually avoided in molecular metals where a maximized overlap is sought. In order to investigate such steric effects in single component conductors, the ethyl group of the known [Au(Et-thiazdt)2] radical complex has been replaced by an isopropyl one to give a novel single component molecular conductor denoted [Au(iPr-thiazdt)2] (iPr-thiazdt: N-isopropyl-1,3-thiazoline-2-thione-4,5-dithiolate). It exhibits a very original stacked structure of crisscross molecules interacting laterally to give a truly three-dimensional network. This system is weakly conducting at ambient pressure (5 S·cm–1), and both transport and optical measurements evidence a slowly decreasing energy gap under applied pressure with a regime change around 1.5 GPa. In contrast with other conducting systems amenable to a metallic state under physical or chemical pressure, the Mott insulating state is stable here up to 4 GPa, a consequence of its peculiar electronic structure.

The complete characterization of novel electropolymerizable organometallic complexes is presented. These are newly synthesized cyclometalated complexes of general formula (PPy)M(O∧N)n(H(PPy) = 2-phenylpyridine, M = Pd(II) or Pt(II), H(O∧N)n= Schiff base). Polymeric thin films have been obtained from these complexes by electropolymerization of the triphenylamino group grafted onto the H(O∧N)nancillary ligand. The redox behavior and the photoconductivity of both of the monomers (PPy)M(O∧N)nand the electropolymerized species have been investigated. The polymeric films of (PPy)M(O∧N)nhave shown a very significant enhancement of photoconductivity when compared to their monomeric amorphous counterparts. The high stability of the obtained films strongly suggests that electropolymerization of cyclometalated complexes represents a viable deposition technique of quality thin films with improved photoconduction properties, hence opening the door to a new class of materials with suitable properties for optoelectronic applications.

Resistive random-access memory (ReRAM) made of organic materials has recently received much attention for application in flexible devices. In the latter, resistive switching is usually obtained thanks to electrochemical effects or charge trapping. This work shows that, under electric pulses, the crystalline molecular Mott insulator [Au(Et-thiazdt)2] exhibits a resistive switching based on an insulator-to-metal transition (IMT). Electric pulses exceeding a threshold electric field of a few kilovolts/centimeter induce a volatile transition, due to an intrinsic, purely electronic effect related to an avalanche phenomenon. Moreover, the application of electric pulses of higher amplitude induces a nonvolatile and reversible resistive switching. Both two-level and multilevel switching between resistances Ronand Roffare observed. At room temperature, a Roff/Ronratio >100 is obtained, which is very high for this kind of switching mechanism and quite promising for ReRAM applications. [Au(Et-thiazdt)2] appears as the first molecular member of a new class of ReRAM called Mott memories.

The synthesis, characterization and electrochemical behaviour of novel monomers for use in sol-gel processes are described. These new compounds include a rigid tetrathiafulvalene (TTF) core substituted by one or two spacers, to which a triethoxysilyl group is covalently bonded. The synthesis is based on the preparation of various cyanoethyl-protected TTF thiolates, deprotection and alkylation of thiolate with 2-bromoethanol, and subsequent condensation of the alcohol function with 3-(triethoxysilyl)propyl isocyanate. The donor ability of the title compounds has been investigated by electrochemical studies. The hydrolytic polycondensation of these new precursors was performed in THF solution in the presence of nucleophile (tetrabutylammonium fluoride, TBAF) or acid (HCl) catalysts. The resulting hybrid solids are highly polycondensed and present organization at both the nanometric (X-ray diffraction) and micrometric (birefringence) scales. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Volatile alkylmercury hydrides are obtained by reduction of the corresponding mercury chlorides and purified by trap-to-trap distillation. The chemical reactivity of these compounds, obtained in pure form, has been studied towards various substrates sensitive to reducing agents.

A hybrid organic inorganic nanostructured material containing a TTF core substituted by four arms exhibited a high level of both condensation at silicon 96 and self-organization as evidenced by X-ray diffraction and an unprecedented birefringent behaviour.

The ligand 1,8-di(1,10-phenanthrolin-2-yl)pyrene has been prepared and complexed with CuI such that three ligands bridge a triangular arrangement of three metals resulting in a symmetrical helical assembly with each pyrene layered between two phenanthrolines at optimum π-stacking distance.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.