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 complex1and 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane
(DAPTA) for complex2] 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 ofLand complexes1and2with the different organic matrices and rationalize
the experimental findings based on the geometries, molecular electrostatic
potential surfaces, and complementarity and HOMO–LUMO gaps.