Methyltin hydrides in fluorosulphuric acid

Abstract

Stannane or the methylstannanes SnMeaPnHn ( n = 1-4) react i n fluorosulphuric acid at low temperature (-90 "C) to produce SnMeSnH,+ ( n = 0-3) and 'H, 13C, and I19Sn n.m.r. spectroscopy have been used in their characterisation. Hydrogen-evolution, I19Sn n.m.r., and Mossbauer evidence is presented t o show that at higher temperatures these species decompose t o Sn2+, Sn2+ plus SnMeZ2+, and SnMe22+ depending o n the starting hydride.Stannane and the methylstannanes have been well studied by a variety of spectroscopic techniques. Flitcroft and Kaesz ' reported n.m.r. data, and a correlation between J(' 19Sn-'H) and the tin-hydrogen stretching frequency v(Sn-H) has been made.* Tin-119 Mossbauer spectra of stannane and some organotin hydrides have been recorded., May and Spijkerman correlated Mossbauer and n.m.r. parameters for the methyltin hydrides.Sawyer and co-workers 5-7 have studied the reactions of organotin hydrides with acids. Di-n-butyltin dihydride reacts with HCI in dioxane to produce di-n-butyltin chloride hydride, with the evolution of 1 rnol of H,. This tin chloride hydride reacts further with an excess of acid to form SnBu",CI, and a further rnol of H,. An exchange reaction between SnBu",CI, and SnBu",H, gives SnBu",CIH.* Stannane reacts with strong acids, under controlled conditions, and Webster and Jolly have shown that SnH,' is produced. They showed that SnH, reacted slowly with strong aqueous acids, at low temperature, to produce 1 rnol of H, for every rnol of SnH,. On warming to room temperature a further 2 rnol of H, were produced. In HS0,F solution, at -78 "C, SnH, reacted rapidly to produce SnH,' and 1 rnol of H,. However, on warming to room temperature, no further H, was evolved. Birchall and Pereira l o have compared 'J(Sn-H) for the series SnH,', SnH,, and SnH,-.Similar behaviour is observed for SnMe, in HSO,F, when solvated SnMe,' and SnMe," are produced together with the evolution of CH,.' ' To our knowledge no one has studied the solvolysis of the methyltin hydrides in strong acids. In this paper we report our results on such reactions and provide n.m.r. spectroscopic evidence for the SnMe,', SnMe,H', SnMeH,+, and SnH,' cationic species in solution and evidence for the decomposition process.

Deuterium isotope effects on the 119Sn shielding constants and spin–spin coupling constants in stannane and the stannonium cation

“…Consideration of BH,, BH4-and AlH3 , A1H4-oindicates derivatives of +3.5, -27.0 and + 84.2, + 11.6 ppm/A, respectively; thus in going from SnH3+ to SnH4 one expects the derivative to decrease algebraically as observed. (15). A , ' J ( ' '~S~~/ ' H ) was found to be between -2.7 and -3.0 Hz, the average value being -2.8 ?…”

“…SnD,,H3-,+ (n 5 3) was prepared (15,17) by the reaction of 0.01 mol of SnD,H4-,, (H:D mole ratio = 2:3) and 4 mL of HS03F (Aldrich), which had been distilled under nitrogen, in a 10-mm 0.d. thick-walled nmr tube.…”

On the existence of trivalent stannyl cations in solution

“…Lambert and Kira therefore suggested trigonal free tin cations in these experiments, contrary to the earlier proposals. 6 By using an empirical shift correlation between tin and silicon,7 as shown in Fig. 1, one should be able to derive a crude prediction of chemical shifts of new complexes as well as obtain an estimate of the Sn chemical shift of the free trigonal stannyl ion.…”

Heterocations in Superacid Systems

“…[HO{B(C 6 F 5 ) 3 } 2 ] − Ar = 2,6-diisoPrC 6 692 Lambert and Kuhlmann 693 [Bu 3 Sn þ H(C 6 F 5 ) 3 B À ], and Kira et al 694 (Bu 3 Sn þ TFPB À ) exhibit 119 Sn NMR chemical shifts in the region d 119 Sn 322-360. Using the empirical correlation between 29 Si and 119 Sn chemical shifts, Arshadi et al 695 concluded that these claimed stannylium ions have, in fact, little ionic character (assuming linear relationship between 29 Si and 119 Sn chemical shifts, the chemcial shift of d 29 Si 225 corresponds to d 119 Sn 1100).…”