Di(imino)aryltin(iv) dichlorides as tectons for heterometallic coordination compounds

Hydrolysis of [2-{(CH2O)2CH}C6H4]2SnCl2 (1) [prepared from 2-[(CH2O)2CH]C6H4MgBr and SnCl4, in 2:1 molar ratio] gave [2-(OCH)C6H4]2SnCl2 (2). Treatment of 2 with the appropriate amine, in the absence of a solvent or catalyst, resulted in the isolation in high yields of [2-(RNCH)C6H4]2SnCl2 [R = 2′-C10H7 (3), 2′,4′,6′-Me3C6H2 (4), PhCH2 (5), Me2NCH2CH2 (6), 2′-PyCH2 (7)]. The reaction of 7 with [Pd(COD)Cl2] provided the heterometallic species [Cl2Pd{2-(2′-PyCH2NCH)C6H4}2SnCl2] (8). The compounds were characterised by multinuclear NMR spectroscopy in solution, and mass spectrometry and IR spectroscopy in the solid state. The molecular structures of 1, 2, 4–7 and 8·CH3CN were established by single-crystal X-ray diffraction. For all diorganotin(IV) dichlorides intramolecular O→Sn or Nimine→Sn coordination results in hypercoordinated species with a distorted octahedral (C,E)2SnCl2 core (E = O, N). The presence of intramolecular N→Sn interactions in solution, responsible for the restriction of free rotation of mesityl groups around the C–N(C) single bonds, is suggested by 1H and 13C NMR data. In the heterometallic dinuclear complex 8 the octahedral coordination around tin is preserved as in 7 and the nitrogen atoms from the pyridyl groups in the pendant arms are coordinated to palladium, leading to a trans-square planar PdCl2N2 core.