Molecular distortion effect on ff-emission in a Pr(III) complex with 4,7-diphenyl-1,10-phenanthroline

The electronic and structural behaviour of a Pr(III) complex with 4,7-diphenyl-1,10-phenanthroline, [Pr(bathophen),(NO), is investigated with respect to the effect of configuration changes on the Pr(III) centre. [Pr(bathophen)(2)(NO3)(3)] luminesces from the excited states of the ligand and the metal ion. The fluorescence, ff-emission (D-1(2) -> H-3(4)), and phosphorescence bonds appear at 394, 608.2 and 482 nm, respectively, in the solid state. In acetonitrile, the complex also shows multiple emissions. From the time-resolved emission and the lifetime measurements, the excitation energy-transfer in [Pr(bathophen)(2)(NO3)(3)] is clarified, that is, the upper excited triplet level of the ligand acts as on energy donor, while the D-1(2), levels of Pr(III)) is the acceptor. Additionally, the emission phenomena of the complex can be modified by molecular distortion, particularly by rotation of the phenyl groups in the ligand.