Investigating the Impact of Packing and Environmental Factors on the Luminescence of Pt(N^N^N) Chromophores.

Four Pt(II)(N^N^N) compounds featuring DMSO coordination at the fourth position were synthesized. Ligands varied in terms of pyridyl central ring (hydrogen/chlorine substituent) and lateral rings (triazoles with CF substitution or tetrazoles). Coordination to pyridine yielded tetra-nitrogen coordinated Pt(II) complexes or Pt-functionalized polymers using commercial 4-pyridyl polyvinyl (PV) or dimethylaminopyridine.

Gold(I) complexes bearing a PNP-type pincer ligand: photophysical properties and catalytic investigations.

The synthesis and characterization of two dinuclear and five tetranuclear gold(I) complexes bearing the 2,6-bis(diphenylphosphinomethyl)pyridine diphosphane ligand (DPPMPY) are herein reported. The reaction between the dinuclear complexes, DPPMPY(AuCl) (1) or DPPMPY(AuBr) (2), with 1 or 2 equivalents of Ag salts yielded five tetranuclear gold(I) complexes, DPPMPYAuX (3-7), differing in the terminal ancillary ligands (X = Cl, Br, acetonitrile) and the counter ions (SbF or BF). The structures of complexes 1, 2, 3, and 5 were confirmed by single-crystal X-ray diffraction studies.

Aggregation of gold(I) complexes: phosphorescence singlet oxygen production.

Herein we report on the synthesis of six new phosphane-gold(I)-4-ethynylaniline complexes (neutral and cationic), with a tris-naphthalene substituted tertiary phosphane bearing a secondary amine as a linker and containing different halogen groups (Cl and Br) in the naphthyl group. We have demonstrated in this work how the careful control of the intermolecular aggregation process can modulate the competition between phosphorescence emission and energy transfer from the triplet state of the gold(I) complexes to produce singlet oxygen.

Homo- and heterometallic chiral dynamic architectures from allyl-palladium(II) building blocks.

New chiral tetranuclear square-like homo- and heterometallamacrocycles containing allyl-palladium and either {Pd(P-P)*} or {Pt(P-P)*} optically pure moieties (P-P* = (2S,3S)--isopropylidene-2,3-dihydroxy-1,4-bis(diphenylphosphanyl)butane ((,)-DIOP) and (2,4)-2,4-bis(diphenylphosphanyl)pentane ((,)-BDPP)) have been obtained by the self-assembly of [Pd(η-2-Me-CH)(4-PPhpy)] and [M(P-P)*(HO)] building blocks in a 1 : 1 molar ratio. The supramolecular assemblies thus prepared [{Pd(η-2-Me-CH)}(4-PPhpy){M(P-P)*}](CFSO) (M = Pd, Pt) have been fully characterised by multinuclear NMR spectroscopy and MS spectrometry. The structures display remarkable differences on their dynamic behaviour in solution that depend on the lability and thermodynamic strength of M-py bonds.

Luminescent Tetranuclear Gold(I) Dibenzo[g,p]chrysene Derivatives: Effect of the Environment on Photophysical Properties.

A new 2,7,10,15-tetraethynyldibenzo[g,p]chrysene ligand () and two tetranuclear gold(I) derivatives containing PPh () and PMe () phosphines were synthesized and characterized by H and P NMR, IR spectroscopy, and high-resolution mass spectrometry. The compounds were studied in order to analyze the effect of the introduction of gold(I) on the supramolecular aggregation and photophysical properties. Absorption and emission spectra displayed broad bands due to the establishment of π π interactions as an indication of intermolecular contacts and the formation of aggregates.

Polypyridyl-functionalizated alkynyl gold(i) metallaligands supported by tri- and tetradentate phosphanes.

A series of alkynyl gold(i) tri and tetratopic metallaligands of the type [Au(C[triple bond, length as m-dash]C-R)(μ-triphosphane)] (R = 2,2'-bipyridin-5-yl or CHN, 2,2':6',2''-terpyridin-4-yl or CHN; triphosphane = 1,1,1-tris(diphenylphosphanyl)ethane or triphos, 1,3,5-tris(diphenylphosphanyl)benzene or triphosph) and [Au(C[triple bond, length as m-dash]C-R)(μ-tetraphosphane)] (R = CHN, CHN; tetraphosphane = tetrakis(diphenylphosphanylmethyl)methane or tetraphos, 1,2,3,5-tetrakis(diphenylphosphanyl)benzene or tpbz, tetrakis(diphenylphosphaneylmethyl)-1,2-ethylenediamine or dppeda) were obtained in moderate to good yields. All complexes could be prepared by a reaction between the alkynyl gold(i) polymeric species [Au(C[triple bond, length as m-dash]C-R)] and the appropriate polyphosphane. An alternative strategy that required the previous synthesis of the appropriate acetylacetonate precursors [Au(acac)(μ-polyphosphane)] ("acac method") was assayed, nevertheless only the polyacac derivatives [Au(acac)(μ-triphosphane)] (triphosphane = triphos and triphosph) and [Au(acac)(μ-tetraphos)] could be isolated and characterized.

Cationic Supramolecular Hydrogels for Overcoming the Skin Barrier in Drug Delivery.

A cationic bis-imidazolium-based amphiphile was used to form thermoreversible nanostructured supramolecular hydrogels incorporating neutral and cationic drugs for the topical treatment of rosacea. The concentration of the gelator and the type and concentration of the drug incorporated were found to be factors that strongly influenced the gelling temperature, gel-formation period, and overall stability and morphology. The incorporation of brimonidine tartrate resulted in the formation of the most homogeneous material of the three drugs explored, whereas the incorporation of betamethasone resulted in a gel with a completely different morphology comprising linked particles.

Sequential Uncaging with Green Light can be Achieved by Fine-Tuning the Structure of a Dicyanocoumarin Chromophore.

We report the synthesis and photochemical properties of a series of dicyanocoumarinylmethyl (DEAdcCM)- and dicyanocoumarinylethyl (DEAdcCE)-based photocages of carboxylic acids and amines with absorption maximum around 500 nm. Photolysis studies with green light have demonstrated that the structure of the coumarin chromophore as well as the nature of the leaving group and the type of bond to be photocleaved (ester or carbamate) have a strong influence on the rate and efficiency of the uncaging process. These experimental observations were also supported by DFT calculations.