Luminescence and Theoretical Studies of Cu(tripod)X [tripod = 1,1,1‐Tris(diphenylphosphanylmethyl)ethane; X – = Halide, Thiophenolate, Phenylacetylide]

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, 69451 Weinheim, Germany, 2005)