The propensity of trans-1,2-cycloalkanediamines (C-3-C-6) to form rigid dinuclear complexes with platinum(II) was tested by reacting these ligands with K[PtCl3(dmso)]. Whereas trans-1,2-cyclopropanediamine and trans-1,2-cyclobutanediamine yielded dinuclear complexes in which the cycloalkane skeleton confines the platinum centers to a distance of ca. 6 Angstrom, trans-1,2-cycropentanediamine and trans-1,2-cycrohexanediamine formed the chelates [PtCl(cycloalkanediamine)(dmso)](+), which precipitated with [PtCl3(dmso)](-) as counterion.