SYNTHESIS AND CHARACTERIZATION OF AQUAPEN TACHLOROPLATINATES(IV) - STRUCTURE OF [K(18-CROWN-6)][PTCL5(H2O)]

The crown ether complex of the aquapentachloroplatinic acid of the com position [H13O6][PtCl5(H4O2)]. 2 (18-cr-6) (2) reacts with K2CO3 and [ (NBu4)-Bu-n]OH in aqueous solution to give [K(18-cr-6)][PtCl5(H2O)] (5 a) and [(NBu4)-Bu-n][PtCl5(H2O)]. 1/2(18-cr-6). H2O (5b), respectively . Both compounds were characterized by microanalysis, vibrational (IR, Raman) and NMR (H-1, C-13, Pt-195) spectroscopy. The X-ray structure analysis of 5a (orthorhombic, Pnma; a=16,550(4), b=18,044(3), c=7,415( 1) Angstrom; Z=4; R1=0,0183; wR2 = 0,0414) reveals that the crystal is threaded by chains built up of [PtCl5(H2O)](-) and [K(18-cr-6)](+) un its There are tight K ... Cl contacts (d(K-Cl1)=3,0881(9) Angstrom) an d O-w-H-O-cr hydrogen bridges (d(O1 ... O2)=2,806(3) Angstrom) between these units. The coordination polyhedron [PtCl5O] has approximately C -4v symmetry.