Rhodamine Complexes. Preparation, Photophysical Properties, and the Structure of

Article abstract of DOI:10.1021/j100341a014

The fluorescent dye rhodamine B has been used as a ligand, binding through its carboxylate group, in complexes of Rh(I), Ir(I), Ir(III), and Pt(II).Slight alteration in the absorption spectrum of the rhodamine chromophore results from its coordination, but profound changes are observed in the luminescence intensity of the coordinated chromophore.In compounds where the rhodamine is bound to a readily oxidized metal center (Rh(I), Ir(I), H2Ir(III) its fluorescence is strongly quenched, but when it is bound to a less easily oxidized metal center (Ir(III)) the rhodamine fluorescence remains intense.From these and other observations we propose electron transfer as the excited-state quenching mechanism.The structure of the title compound reveals an unexpected packing arrangement, best described as linear chains of Rh-rhodamine cations held together by rhodamine-rhodamine interactions.