Hydrolysis of bis((trimethylsilyl)methyl)tin dihalides. Crystallographic and spectroscopic study of the hydrolysis pathway

The synthesis and characterization by multinuclear NMR spectroscopy of the diorganotin dihalides (Me3SiCH2)2SnX2 (1, X = Cl; 2, X = Br), the diorganotin dichloride water adduct (Me3SiCH2)2SnCl2&middot;H2O (1a), the dimeric tetraorganodistannoxanes [(Me3SiCH2)2(X)SnOSn(Y)(CH2SiMe3)2]2 (3, X = Y = Cl; 4, X = Br, Y = OH; 5, X = Br, Y = F; 6, X = Y = OH; 8, X = Cl, Y = OH), and the molecular diorganotin oxide cyclo-[(Me3SiCH2)2SnO]3 (7) are reported. The structures in the solid state of compounds 1a, 3, 6, and 7 were determined by single-crystal X-ray analysis. In toluene solution, the hydroxy-substituted tetraorganodistannoxane 6 is in equilibrium with the diorganotin oxide 7 and water. The eight-membered diorganotin oxide cyclo-[(Me3SiCH2)2SnO]4 (7a) is proposed to be involved in this equilibrium. On the basis of the results of this and previous works, a general hydrolysis pathway is developed for diorganotin dichlorides containing reasonably bulky substituents.<br /

[¹H,¹⁵N] Heteronuclear single quantum coherence NMR study of the mechanism of aquation of platinum(IV) ammine complexes

The aquation and hydrolysis of a series of platinum(IV) complexes of the general form cis, trans, cis-[PtCl2(X)2(15NH3)2] (X = Cl−, O2CCH3−, OH−) have been followed by [1H,15N] Heteronuclear Single Quantum Coherence NMR spectroscopy. Negligible aquation (<5%) is observed for the complexes where X = O2CCH3− or OH− over 3−4 weeks. Aquation of cis-[PtCl4(15NH3)2] (1) is observed, and the rate of aquation increases with increasing pH and upon the addition of 0.01 mol equiv of the platinum(II) complex cis-[PtCl2(15NH3)2] (cisplatin). The first aquated species formed from cis-[PtCl4(NH3)2] has one of the axial chloro groups (relative to the equatorial NH3 ligands) replaced by an aqua/hydroxo ligand. The second observed substitution occurs in an equatorial position. Peaks that are consistent with five of the eight possible aquation species were observed in the NMR spectra.\u