Ligand and Gold(I) Fluorescein–AIEgens as Photosensitizers in Solution and Doped Polymers

Abstract

The synthesis of fluorescein propargyl diether (L) and two different dinuclear gold(I) derivatives containing a water-soluble phosphane [1,3,5-triaza-7-phosphatricyclo[3.3.1.13.7]decane (PTA) for complex 1 and 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane (DAPTA) for complex 2] has been successfully performed. All compounds display intrinsic emission from fluorescein, being less intense for gold(I) complexes due to the heavy-atom effect. All compounds aggregate in acetonitrile/water mixtures with the formation of larger aggregates for those samples containing more water content, as evidenced by dynamic light scattering and small-angle X-ray scattering experiments, in agreement with the absorption and emission data. The emission of the samples increases when they are used to obtain luminescent materials with four different organic matrices [poly(methyl methacrylate, polystyrene (PS), cellulose, and Zeonex]. The compounds display very high values of singlet oxygen (1O2) production in dichloromethane. Singlet oxygen production was also evaluated in the doped matrices, being the highest in PS and with an exciting increase on PS microspheres. Density functional theory (BP86-D3) and GFN2-xTB calculations were used to model the assembly of L and complexes 1 and 2 with the different organic matrices and rationalize the experimental findings based on the geometries, molecular electrostatic potential surfaces, and complementarity and HOMO–LUMO gaps.

Supramolecular luminescent Pt(ii) tweezers: aggregation studies and 1O2 production

“…Moreover, this level of theory has been recently used by us to explain the aggregation of Au-complexes. 61 The binding energies were computed by subtracting the sum of the energies of the monomers to the energy of the dimer. Solvent effects were taken into consideration using the COSMO-RS method 62 as implemented in Turbomole program.…”

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

“…An intermediate situation would be doping organic matrices, such as poly(methyl methacrylate) (PMMA) or polystyrene (PS). Based on our previous experience, the dispersion of luminophores within this type of matrices may improve their emission properties regarding emission quantum yields and lifetimes. ,− The recorded emission spectra indicate that the intermolecular packing, responsible for the resulting MMLCT emission is observed to be not favored in these media while the 3 IL monomer is the emissive species instead (Figure and Table ). Vibronically structured bands are herein displayed due to a well distribution of the molecules within the thin film media, and they present, as expected, higher emission quantum yields and larger emission lifetimes .…”

Effect of substituents on the 1O2 production and biological activity of (N^N^N)Pt(py) complexes

“…Some TMCs have been explored as PS, e.g. Ru(II) polypyridyl complexes, 11 iridium(III), 12 gold(I) complexes, [13][14][15] and platinum(II) complexes. [16][17][18][19] Focusing on platinum compounds, it is well known that these types of TMCs have been extensively explored as anticancer drugs since the discovery of cisplatin.…”

“…Some TMCs have been explored as PS, e.g. Ru( ii ) polypyridyl complexes, 11 iridium( iii ), 12 gold( i ) complexes, 13–15 and platinum( ii ) complexes. 16–19…”