Room temperature tin-119 Mössbauer spectra of unassociated tin compounds

Abstract

Room-temperature ¹¹⁹Sn Mössbauer spectra have been obtained for Ph₃SnCl, Me₂SnCl₂, [Ph₃SnMn(CO)₅], Ph₃Sn(bzbz), Ph₄Sn, [Me₄N][Ph₃SnCl₂], Me₂Sn(acac)₂, [{Fe(CO)₂(cp)}₂SnCl₂], and [{Me₂Sn(OH)NO₃}₂](acac and bzbz are the anions of acetylacetone and dibenzoylmethane). X-Ray crystal structures for all compounds except [Me₄N][Ph₃SnCl₂] show no evidence for strongly associated polymeric structures. Because the magnitude of the Mössbauer effect is surprisingly large (ca, 1% absorption) in some cases, the observation of a room-temperature ¹¹⁹Sn spectrum can no longer be taken by itself as strong evidence for a polymeric structure. The quadrupole splittings indicate that Ph₃SnCl remains four-co-ordinate from 80 to 295 K, while Me₂SnCl₂ becomes more weakly associated over the same temperature range. From the Goldanskii-Karyagin asymmetry in the room temperature spectrum of trans-Me₂Sn(acac)₂, the difference in mean square amplitudes parallel and perendicular to the Me–Sn–Me axis, < X_∥² > – < X_⊥² > = 2.8 ± 0.6 × 10^–18 cm², is in good agreement with the crystallographic value of 2.92 × 10^–18 cm².