Synthesis, Structure, and Reactions of 10-Sn-5 Organotin Ate Complexes

Abstract

Stable anionic 10-Sn-51) species, tetraalkylammonium bis[α,α-bis(trifluoromethyl)benzenemethanolato(2−)-C2,O]alkylstannates(1−) [2a (R = Ph), 2b (R = p-CH3C6H4), 2c (R = n-Bu), and 2d (R = Me)], were prepared. Reaction of 2a and 2b with sulfuryl chloride gave chlorostannate (3a), which could be converted to fluorostannate (3b). 3a and 3b reacted with organolithium reagents to give 2. The X-ray crystallographic analysis of 3b-n-Bu4N+ revealed a distorted trigonal bipyramidal structure.

Synthesis, structure, and alkynylation reactivity of alkynyl-silicate, -germanate, and -stannate

“…Similarly, in the 119 Sn NMR spectra of 2c , a characteristic singlet was observed in an upfield region ( δ Sn −186.4 ppm) in relation to that of Bu 3 SnCCPh ( δ Sn −65.8 ppm) 15 and the analogous methylstannate ( δ Sn −77.7 ppm). 16 These NMR results confirmed the formation of pentacoordinated and alkynyl-bound silicate 2a and stannate 2c .…”

The synthesis and structure of a dianionic species with a bond between pentacoordinated tin atoms: bonding properties of the tin–tin bond

“…Nevertheless, the apical Sn-O bond lengths are slightly longer than those of the tetrabutylammonium fluorostannate bearing the same bidentate ligands (2.101( 6) and 2.110(6) Å). 37 The O1-Sn1-O2 angle (166.0(4)°) of 7 is considerably narrower than that of fluorostannate 8 (178.7(3)°). The Sn1-O1 and Sn1*-O2* bonds are staggered relative to each other, as exhibited by the O1-Sn1-Sn1*-O2* torsion angle (58.6(4)°), to avoid the steric repulsion of the bulky bidentate ligands.…”

“…S12 †), which is different from the literature value of chlorostannate (δ Sn −127.6 ppm). 37 Further reaction of this intermediate cleaved the Sn-Sn bond and gave clean conversion to chlorostannate 9 (Scheme 2). The reactivity of 7 is different from that of 5 and 6, both of which underwent protonation on oxygen atoms bonded to silicon and germanium atoms without homonuclear bond cleavage, upon treatment with hydrochloric acid.…”

“…However, pentacoordinated fluorostannate 8, bearing two sets of the electron-withdrawing C,O-bidentate ligand, is known to react with nucleophiles and was used for the synthesis of stannates. 37 It is expected that a single electron reduction of 8 would give lithium fluoride elimination and generate the corresponding tin radical anion. Dimerization of the radical anion would yield the distannate similarly to the formation of the previously reported disilicates 5 41 and digermanates 6.…”

“…A reason for this is simply not ascribed to the instability of the ate-type structure of each tin atom as several stable pentacoordinated ate-type tin compounds, which show a trigonal bipyramidal (TBP) structure around the tin atom, have been synthesized by taking advantage of electron-withdrawing bidentate ligands. 7,[37][38][39][40] We previously reported the synthesis of disilicate 5 41,42 and digermanate 6, 43 which are dianionic species containing a bond between two pentacoordinated ate-type silicon and germanium atoms, respectively. A tin analogue of 5 and 6 could be a challenging synthetic target considering the much smaller bond energy of the Sn-Sn bond in comparison to the Si-Si and Ge-Ge bonds.…”