Gallium(III) and Indium(III) Complexes with meso-Monophosphorylated Porphyrins: Synthesis and Structure. A First Example of Dimers Formed by the Self-Assembly of meso-Porphyrinylphosphonic Acid Monoester

The synthesis and structural characterization, both in solution by means of ¹H and ³¹P NMR and UV–vis spectroscopies and in the solid state by X-ray diffraction on single crystal, of a series of gallium­(III) and indium­(III) meso-mono­(diethoxyphosphoryl)­porphyrins bearing different peripheral substituents as well as the corresponding monoesters and phosphonic acids are reported. This work describes the first example of the X-ray structure of a self-assembled dimer formed via strong binding between the oxygen atom of the phosphonate substituent and the gallium­(III) cations of adjacent porphyrin molecules [Ga–O = 1.9708(13) Å].