RESUMEN
Pt(IV) complexes trans-Pt(PEt3)2(R)(Br)3 (R = Br, aryl and polycyclic aromatic fragments) photoeliminate molecular bromine with quantum yields as high as 82%. Photoelimination occurs both in the solid state and in solution. Calorimetry measurements and DFT calculations (PMe3 analogs) indicate endothermic and endergonic photoeliminations with free energies from 2 to 22 kcal/mol of Br2. Solution trapping experiments with high concentrations of 2,3-dimethyl-2-butene suggest a radical-like excited state precursor to bromine elimination.
RESUMEN
Contrary to expectations, molecular bromine addition to trans-Pt(Br)(9-anthracenyl)(PEt(3))(2) does not result in Pt oxidation or Pt-C bond cleavage but rather in selective multiple bromination of the anthracenyl ligand. The resulting complexes are highly photoluminescent in the blue region due to triplet-triplet annihilation induced delayed fluorescence from the anthracene.