Reinvestigation of the crystal and molecular structures of penta-amminenitrosylruthenium trichloride hydrate and trans-tetra-ammine-hydroxonitrosylruthenium dichloride

Abstract

The crystal and molecular structures of the title compounds have been reinvestigated and solved by Patterson and Fourier methods by use of diffractometer data. Crystals of [Ru(NH₃)₅(NO)]Cl₃,H₂O are orthorhombic, space group Pn2₁a, a= 11·864(7), b= 6·878(5), c= 14.l92(9)Å, Z= 4. The structure was refined by full-matrix methods to R 0·047 (971 observed reflections). The ruthenium ion is octahedrally co-ordinated by six nitrogen atoms, with Ru–NO 1·770(9), N–O l.172(14), and Ru–NH₃ 2·017–2·133 Å. Because of correlation effects only two distances (cis-Ru–NH₃) are regarded as true measurements of the bond lengths. Crystals of trans-[Ru(OH)(NH₃)₄(NO)]Cl₂ are monoclinic, space group C2/m(assumed), a= 11·422(3), b= 7·365(2), c= 1l·157(3)Å, β= 109·09(2)°, Z= 4. Full-matrix refinement for 2398 observed reflections, gave R 0·031. The ruthenium ion is octahedrally co-ordinated with Ru–NO 1·735(3), Ru–NH₃ 2·099(3) and 2·106(3), Ru–OH, 1·961 (3), N–O l·159(5)Å, and Ru–N–O 173·8(3)°. The Ru–OH distance is shorter than expected from covalent radii considerations.