Structure and spectroscopic properties of porphyrinato group 14 derivatives: Part I - Phenylacetylido ligands

A series of bis(phenylacetylido)(porphyrinato) E(IV) (E=Si, Ge, Sn) derivatives were obtained by reacting lithium phenylacetylide with the corresponding bis(chlorido)(porphyrinato) E(IV) precursors. Crystal structure determinations demonstrated that the trans-coordinated acetylide ligands deviate from their expected ideal geometry. Density functional theory calculations and comparison of the packing of the molecules among the homologous series of Si(IV), Ge(IV) and Sn(IV) revealed causes for the deviation from the simple valence shell electron pair repulsion model. Fluorescence and phosphorescence of these organometallic group 14 derivatives were studied and the results are compared to the literature-known properties of the related bis(chlorido)(porphyrinato) E(IV) compounds (E=Si, Ge, Sn). The first crystal structure of a porphyrinato Ge(IV) compound with σ-bonded acetylide ligands is reported.