Luminescence and theoretical studies of Cu(tripod)X [tripod = 1,1,1-tris(diphenylphosphanylmethyl)ethane; X- = halide, thiophenolate, phenylacetylide]

Article abstract of DOI:10.1002/ejic.200400959

Complexes of the type Cu^I(tripod)X [tripod = 1,1,1 -tris (diphenylphosphanylmethyl)ethane; X^- = Br^-, I^-, PhS^-, PhC≡C^-] are phosphorescent in solution and in the solid state (λ_max ≈ 465 nm). Calculations show that the emissive triplet is of mixed MLCT/LLCT character. The emission is facilitated by the rigid tetrahedral structure, which is imposed by the tripod ligand. Accordingly, a distortion towards a square-planar geometry, which should occur upon MLCT excitation, is prevented. On the other hand, in the triplet state the phenyl substituents of the phosphane ligands undergo a rotation which favours radiationless deactivation. As a result, the emission efficiency is relatively small in solution, but much higher in the solid state owing to the rigidity of the lattice. Wiley-VCH Verlag GmbH & Co. KGaA, 2005.