Synthesis and characterisation of twelve Sn^IV diaryls and formation of a Sn^III triaryl

Ten new crystalline compounds of formula (i) [{Sn(Ar^N2)₂(μ-E)}₂] [E = O (2), S (3), Se (4), Te (5)], (ii) [Sn(Ar^N2)₂(ER)₂] [ER = SCH₂Ph (6), SePh (7), TePh (8)], (iii) [Sn(Ar^N2)₂(Br)R] [R = CH(SiMe₃)₂ (9), Bu^t (10)] and (iv) [Sn(Ar^N2)₂{CH(SiMe₃)₂}][BPh₄] [Ar^N2 = C₆H₃(NMe₂)₂-2,6 (11)] have been prepared and identified by microanalysis, EI-mass spectrometry and multinuclear NMR spectroscopy, and for 2, 5, 6, 8 and 11 by single crystal X-ray diffraction. Whereas in the solid state, each of the latter five has only one of its two NMe₂ substituents of each [Ar^N2]⁻ ligand close to the tin atom (<3.1 Å), in solution at ambient temperature the NMe₂ groups are characterised by a single ¹H and ¹³C signal. The known compounds [Sn(Ar^N2)₂(NCE)₂] [E = O (12), S (13)] were synthesised by a new route: the redox reaction between [Sn(Ar^N2)₂] (1) and 2AgNCE. Irradiation of a toluene solution of 1 at 298 K afforded a persistent radical assigned as [˙Sn(Ar^N2)₃] (14).