An aqueous solution of H(2)[PtCl(6)].6 H(2)O reacts with crown ether 18-crown-6 to give [H(13)O(6)][PtCl(5)(H(4)O(2))]. 2(18-cr-6)(1) (1) and (H(3)O)(2)[PtCl(6)].2(18-cr-6) (2a). In the presence of HCl, only 2a is formed; in an analogous manner, (H(3)O)(2)[PtCl(6)].2(15-cr-5).2 H(2)O (2b) and (H(3)O)(2)[PtCl(6)].2(DCH-18-cr-6)(1) (2c) were obtained. 1 is gradually decomposed in water to give [PtCl(4)(H(2)O)(2)].(18-cr-6).2H(2)O (3). 1-3 were characterized by microanalysis and IR and NMR spectroscopy ((1)H, (13)C, (195)Pt). The X-ray structure analysis of 1 (orange needles; space group P2(1)2(1)2(1), a = 7.938(1) Å, b = 15.691(2) Å, c = 34.861(4) Å; Z = 4) shows an anionic entity [PtCl(5)(H(4)O(2))](-) and a cationic entity [H(13)O(6)](+) which are separated by a crown ether molecule 18-cr-6. The [H(13)O(6)](+) cations exhibit the structure [H(3)O(H(4)O(2))(2)(H(2)O)](+) and are also separated by crown ether molecules in such a way that the crystal is threaded by chains built up of 18-cr-6/[H(13)O(6)](+) units at which the 18-cr-6/[PtCl(5)(H(4)O(2))](-) moieties are fixed as lateral branches. Thus, the cations [H(13)O(6)](+) are embedded in three crown ether molecules. All terminal hydrogens are involved in hydrogen bridges to oxygen atoms of the crown ether molecules. The O(w).O(cr) distances are distinctly longer in the mean than the O(w).O(w) distances within the [H(13)O(6)](+) moiety.

Al-free layered sodium silicate magadiite has been used as the host material for the stabilisation of [Pt(NH3)4] 2+ ions via intercalation and/or ionexchange reactions. The stabilisation of Pt(NH3)4] 2+ ions in between the layers of Na-magadiite was confirmed by thermogravimetric analysis (TGA), where increased decomposition temperatures were observed for the intercalated materials. The intercalation behaviour of Na-magadiite was evident from the significant uptake of Pt ions (22.2 wt.%). When silica gel was used as the host matrix, negligible uptake of Pt ions (1.3 wt.%) was noticed. The X-ray diffraction (XRD) measurements revealed no appreciable change in the basal spacing of the intercalated materials. Nevertheless, the decrease in the intensity of the 001 peak with increasing Pt loadings (from 13.0 to 22.2 wt.%) substantiated the intercalation of [Pt(NH3)4] 2+ ions within the interlayer spaces of Na-magadiite. The transmission electron microscopy (TEM) studies of the intercalated materials revealed that [Pt(NH3)4] 2+ ions were homogeneously intercalated in the magadiite matrix, ranging from 2-3 nm. Subsequent calcination of the intercalated materials at 600 °C in air led to the formation of Pt nanoparticles supported on silica. The results of XRD and TEM indicated that Pt nanoparticles were highly dispersed on the silica support and were in the range of 5-12 nm. Moreover, chemical analyses confirmed the high loading of Pt on silica in agreement with the TGA results.

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Crown ether complexed pentachloro(aqua)platinic acid, (H30)[PtCl5(H20)]-2(18-cr-6) •6H20 (1) reacts with glycine, L-alanine, and DL-2-aminobutyric acid to give ds-[PtCl4(0-glyH)(H20 )](1 8 -cr-6 )H 20 (4a)1 and ds-[PtCl4(0-amacH)(H2O)](18-cr-6) (amacH = alaH 4b, abuH 4c), respectively, as well as (amacH2)2[PtCl6]-2( 18-cr-6) (amacH = glyH 5a, alaH 5b, abuH 5c). The crown ether complexed hexachloroplatinic acid, (H30 ) 2[PtCl6]-2(18-cr-6) (2), reacts with glycine to afford (glyH2)[PtCl4(yV,0-gly)]-2(18-cr-6)1.25H20 (6).The structures of 4b and 6 were determined by X-ray diffraction. The alanine ligand in 4b is a zwitterion that is coordinated to platinum by one oxygen atom of the carboxylate group only. The other oxygen atom is engaged in a strong hydrogen bond to the ds-coordinated aqua ligand. The glycinato ligand in 6 is /V,(9-coordinated at platinum forming an anion [PtCl4(/V,0-gly)]_ . The other oxygen atom of the carboxylate group is involved in a strong hydrogen bridge to the cation (glyH2)+. In both complexes hydrogen bridges are formed between the -N+H3 and -NH2 groups of the amino acid ligands and the oxygen atoms of the crown ether molecules. Ergebnisse und DiskussionWäßrige Lösungen von (H30)[P tC l5(H-,0)] • 2( 18-cr-6)-6H20 (1) reagieren mit Glycin (glyH), L-Alanin (alaH) und DL-2-Aminobuttersäure (abuH)

Highly loaded Pt nanoparticles (20 wt%) on silica were prepared intercalation of [Pt(NH 3 ) ilerite) in air at 380°C for 5 h. Transmission electron microscopy revealed that the size of the Pt particles was in the range 2-5 nm.