Organotin(IV) Alkoxides, Siloxides, and Related Stannoxanes. Characterisation and Thermogravimetric Studies

Abstract

A series of C,O‐chelated organotin(IV) alkoxides, L₂PhSnO^tBu (4), L₂PhSnOMe (6), L₂Sn(O^tBu)₂ (11), and siloxides L₂PhSnOSiPh₃ (3), L₂Sn(OSiPh₃)₂ (10) (L=[2‐(CH₂O)₂CH]C₆H₄), was prepared by salt elimination reactions. They were obtained from the organotin(IV) iodides L₂PhSnI (1) or L₂SnI₂ (2) upon reactions with ^tBuOK, MeONa or Ph₃SiONa, respectively, in dry THF or methanol. Under non‐inert conditions, compounds 4 and 6 undergo combined hydrolysis and condensation to give the hexaorganodistannoxane (L₂PhSn)₂O (5). The stannoxane 5 is easily hydrolysed to L₂PhSnOH (7), which quickly converts back when heated. Basic hydrolysis of diiodide 2 produces the cyclic oxide (L₂SnO)₃ (8). Its reaction with an equimolar amount of Ph₃SiONa gives only a mixture of the expected L₂SnI(OSiPh₃) (9), 10 and the precursor, 2. Yet, 8 shows a unique reactivity pattern when combine with m‐tolyl boronic acid, affording stannaboroxane (L₂SnO)₂OB(m‐tol) (12). All the isolated species were characterised in solution by NMR spectroscopy and mass spectrometry. The solid‐state molecular structures of 1–5, 10–12 were established by single‐crystal X‐ray diffraction (XRD). Additionally, thermogravimetric analysis of 3–5, 8, 10, and 12 was conducted.