Structure and vibrational spectra of cis-diaquatetra-chloroplatinum(IV)-(18-crown-6)-water (1/1/2), cis-[PtCl₄(H₂O)₂]·(18-cr-6)·2H₂O

Abstract

The title compound, cis-[PtCl 4 (H 2 O) 2 ] Á (18-cr-6) Á 2 H 2 O (3), crystallizes from water in the orthorhombic space group Pbcn with lattice constants a 7.9842(12) # e, b 16.550(3) # e, c 18.027(4) # e, Z 4. The crystal structure was solved by direct methods. The refinement converged to final wR2 0.0485 for 2307 data (R1 0.0187 for 1672 observed reflections). The platinum complex cis-[PtCl 4 (H 2 O) 2 ] exhibits crystallographically imposed C 2 symmetry with small deviations from C 2v symmetry, only. Each of the two aqua ligands forms an O± ±HÁ Á ÁO hydrogen bond to a water molecule in such a way that H 4 O 2 units are yielded. Their three terminal hydrogen atoms form O± ±HÁ Á ÁO hydrogen bonds to three oxygen atoms of the crown ether molecule. Thus, the crystal is threaded by chains built up of 18-crown-6/cis-[PtCl 4 (H 2 O) 2 ] Á 2 H 2 O units. The crown ether exhibits crystallographically imposed C i symmetry and D 3d symmetry in rough approximation. The Raman and IR spectra of 3 are as expected for a complex [PtCl 4 (H 2 O) 2 ] with aqua ligands in mutual cis position. # by Oldenbourg Wissenschaftsverlag, Mu Ènchen