195Pt and 1H NMR study of the products of hydrolysis of Pt(L)X2, where L is an ethylenediamine derivative, and the crystal structure of [Pt(N,N-dimethylethylenediamine) (μ-OH)]2 (NO3)2
✍ Scribed by Fernande D. Rochon; Robert Melanson; André Morneau
- Publisher
- John Wiley and Sons
- Year
- 1992
- Tongue
- English
- Weight
- 961 KB
- Volume
- 30
- Category
- Article
- ISSN
- 0749-1581
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✦ Synopsis
Abstract
The hydrolysis reactions of complexes of the type Pt(L)X~2~ where L is ethylenediamine (en), N,N‐ dimethylenediamine (N,N‐Me~2~en), N,N‐dimethylenediamine (N,N′‐Me~2~en) and N,N,N′, N′‐tetramethylethylenediamine (Me~4~en) were studied. The halo ligands were removed by precipitation with AgNO~3~ and the pH of the resulting filtrate, which was about 2, was adjusted to 5.8 (pD = 6.2). The study of the products formed was carried out by multinuclear NMR spectroscopy. The ^195^Pt NMR spectra showed the presence of several hydrolysed products, especially with en. The hydroxo‐bridged dimer can be synthesized in a pure state with all the ligands except en. The results on the latter ligand contradict the published results on the synthesis of the en hydroxo‐bridged dimer whose biological properties were studied. When Pt(L)I~2~ is used as starting material a small quantity of chloro species was always observed, indicating that the reactant contained a small quantity of Pt(L)ICI. The crystal structure of the [Pt(N,N‐Me~2~en)(μ‐OH)]~2~(NO~3~)~2~ dimer was determined. The compound belongs to the __P__2~1~/c space group, with a = 8.262(5), b = 10.960(8), c = 11.405(8), β = 121.07(5)°, Z = 2 and ρ~calc~ = 2.720 mg m^−3^. The results showed that this is the trans isomer with an inversion centre between the two Pt atoms. There is a considerable strain inside the four‐membered ring, as shown by the reduced internal angles OPtO′ = 79.1(6)^0^ and PtOPt′ = 101.0(6)°.