In the square-planar cycloplatinated complex of R-phenylethylamine, both additional substituents, an anionic iodo and a neutral donor ligand, have been replaced by chelating ethylenediamine. A very pronounced trans influence is observed in the cationic product complex: Two significantly different bond distances to the chelating ligand are found, the longer in trans geometry to the coordinated carbon atom. The positive charge of the monocationic complex is balanced by an uncoordinated iodide. This target solid crystallizes with four independent cations and anions in the unit cell; pairs of complex cations related by pseudo-inversion are stabilized by T stacking. Classical N-H I hydrogen bonds lead to a layer structure in the (0 1 0) plane.