Diorganotin(iv) 2-pyridyl selenolates: synthesis, structures and their utility as molecular precursors for the preparation of tin selenide nanocrystals and thin films

Abstract

Reactions of R₂SnCl₂ (R = Me, Et, ^tBu) with NaSeC₅H₃(R′-3)N (R′ = H or Me) gave complexes of the composition [R₂Sn{2-SeC₅H₃(R′-3)N)}₂], which on treatment with R₂SnCl₂ afforded chloro complexes, [R₂Sn{2-SeC₅H₃(R′-3)N}Cl]. These complexes were characterized by elemental analyses and UV–vis and NMR (¹H, ¹³C, ⁷⁷Se and ¹¹⁹Sn) spectroscopy. The crystal structures of [R₂Sn(SeC₅H₄N)₂] (R = Me or ^tBu) and [Me₂Sn{2-SeC₅H₃(Me-3)N}Cl] were determined by single crystal X-ray diffraction. The tin atom in the former two structures acquires a skew trapezoidal configuration, whereas in the latter it adopts a distorted trigonal bipyramidal geometry. Thermolysis of [R₂Sn(2-SeC₅H₄N)₂] (R = Me, Et or ^tBu) and [Et₂Sn{2-SeC₅H₃(Me-3)N}₂] in oleylamine (OA) afforded tin selenide nanostructures. Thin films of SnSe were deposited on glass and silicon substrates by the AACVD of [^tBu₂Sn(2-SeC₅H₄N)₂]. The nanostructures and thin films were characterized by XRD, EDX, AFM, SEM, TEM and SAED techniques. The photovoltaic properties of the thin films have been evaluated.