Platinum(IV) complexes containing a cationic amine ligand: crystal structure of [(2-aminoethyl)ammonium]pentachloroplatinum(IV) monohydrate

Abstract

The complex [PtCl(dmso)(en)]Cl (dmso = dimethyl sulphoxide, en = 1,2-diaminoethane) reacts with concentrated HCl to give one-end displacement of the diamine and inner-sphere oxidation of Pt^II to Pt^IV by dmso which is reduced to dimethyl sulphide (dms). The complex [PtCl₄(dms)(Hen)]Cl which is formed reacts further with chloride ion to displace dms and form [PtCl₅(Hen)]. The complex [PtCl₅(Hen)]·H₂O crystallizes in the orthorhombic space group Ccm2₁ with a= 15.388(8), b= 6.890(5), c= 9.882(6)Å, and Z= 4. The structure has been solved by Patterson and Fourier methods and refined by full-matrix least squares to R= 0.027 for 543 observed reflections. The structure consists of zwitterionic [(2-aminoethyl)ammonium]pentachloroplatinum(IV) species and water molecules of crystallization; in the complex the metal is octahedrally surrounded by five chlorine atoms (Pt–Cl 2.294–2.306 Å) and a nitrogen atom from the monoprotonated diamine [Pt–N 2.050(4)Å]. The water molecules of crystallization are not involved in hydrogen bonds with either chlorine or nitrogen atoms of the complex.