Structural study of bonding in halogeno ruthenium complexes: Application to ruthenium nitrosyls

The halogeno nitrosyl ruthenium complexes are studied using their structural characteristics as basis. The structures of K2RuNOX5 (X=Cl, Br, I) have been determined or redetermined. The study of the bond lengths Ru-Cl is, in a first part, placed in the general frame of the chlorocomplexes of ruthenium havingσ andσ+π type ligands. The comparison points to a lengthening of the Ru-Claxial bond in [RuNOCl5]2−, which is opposite to the trans shortening effect up to now considered. A second part deals with the deformation of the octahedral coordination of the ruthenium atom. In [RuNOX5]2−, the distance from the ruthenium to the equatorial plane varies with the position ofX in the spectrochemical series. The role of thedxy orbital in the geometry of these ions is discussed.