Syntheses, structural studies and spectroscopic characterisation of pyridyl-phthalimide complexes of fac-(CO)(3)Re-I-diimines

The mono-dentate ligands, 3-aminomethyl-N-phthalimido-pyridine (L1) and 3-amino-N-phthalimido-pyridine (L2), were synthesized using a solvent-free melt method. These ligands were then used to access three pairs of functionalized luminescent ReI complexes of the generic type fac-Re(CO)3(diimine)(Ln)(BF4) where diimine = 4,4'-dimethyl-2,2'-bipyridine (dmb); 2,2'-bipyridine (bpy); 1,10-phenanthroline (phen). X-ray crystallog. was used to structurally characterize five of the complexes showing that in the cases of the L1 species the phthalimide unit is adjacent to and coplanar with the coordinated diimine ligand. Soln. state UV-visible absorption, electrochem. and IR studies confirm that the proposed formulations and coordination modes exist in soln. The photophys. studies show that the visible emission from each of the six complexes is 3MLCT at room temp. Within each pair of complexes the precise energy of the emission was subtly dependent upon the axial ligand, Ln with luminescence lifetimes in the range 121-288 ns. on SciFinder (R