Reactivity of a carbonyl moiety in organotin(iv) compounds: novel Pd(ii) and Cu(ii) complexes supported by organotin(iv) ligands

Abstract

Hydrolysis of [2-{(CH₂O)₂CH}C₆H₄]SnPh₃ (1) results in the isolation of [2-(OCH)C₆H₄]SnPh₃ (2) in a very good yield. Reduction of 2 with NaBH₄ gives an almost quantitative yield of [2-(HOCH₂)C₆H₄]SnPh₃ (3), when 2 is treated with appropriate amines in the absence of any solvent, [2-(4′-PyCH₂NCH)C₆H₄]SnPh₃ (4) and [2-{3′,5′-(MeOOC)₂–C₆H₃NCH}C₆H₄]SnPh₃ (5) are isolated in high yields. Adding NaBH₄ to a THF solution of 4 leads to [2-(4′-PyCH₂NH–CH₂)C₆H₄]SnPh₃·BH₃ (6), the first aryltin(IV) compound with a ligand containing a secondary amine functional group coordinated to the metal centre. The reaction of 4 with [PdCl₂(NCMe)₂] and [Cu(hfac)₂·(H₂O)] (hfac = hexafluoroacetylacetonate) in a 2 : 1 molar ratio gave the corresponding heterometallic complexes [{2-(4′-PyCH₂NCH₂)C₆H₄SnPh₃}₂PdCl₂] (7) and [{2-(4′-PyCH₂NCH₂)C₆H₄SnPh₃}₂Cu(hfac)₂] (8), respectively. The purity of the compounds was confirmed by elemental analysis and high-resolution mass spectrometry. Multinuclear NMR spectroscopy was used to investigate the solution behaviour of these compounds and the molecular structures for 1, 2, and 4–8 were established by single-crystal X-ray diffraction.