Methylene-Bridged Tri- and Tetratin Compounds as Lewis Acids

Abstract

Syntheses of a series of trinuclear tin compounds, (Ph2XSnCH2)2SnXPh (2, X = Ph; 6, X = F; 8, X = Cl) and (PhCl2SnCH2)2SnCl2 (10) and tetranuclear tin compounds (Ph2XSnCH2SnXPh)2CH2 (3, X = Ph; 7, X = F; 9, X = Cl) are reported, and the crystal structure of [(Ph2FSnCH2)2SnFPh·F]-[C12H24O6·K]+ (6b) is described. Variable temperature 119Sn and 19F NMR studies indicate that the structure observed for the anion in 6b in the solid state is retained in solution. There is no NMR evidence for the formation of 1:2 adducts with fluoride ion, although such species are identified in acetonitrile solutions from electrospray mass spectrometry (ESMS). 119Sn NMR spectral data indicate that reaction of trinuclear tin compound 8 with [(Ph3P)2N]+Cl- and HMPA results in formation of the 1:1 complexes [(Ph2ClSnCH2)2SnClPh·Cl]-[(Ph3P)2N]+ (8a) and (Ph2ClSnCH2)2SnClPh·[(CH3)2N]3PO (8b), respectively. In contrast, 19F and 119Sn NMR data show that the tetranuclear tin compound 7 reacts with fluoride ion to give a stable 1:2 adduct [(Ph2FSnCH2SnFPh)2CH2·2F]2-2[Bu4N]+ (7b) in solution, being no NMR evidence for formation of a 1:1 adduct. However, ESMS indicates the presence of both 1:1 and 1:2 adducts in acetonitrile solution.

1,1,3,3,14,14,16,16,18,18,29,29-Dodecamethyl-3,14,18,29-tetrasila-1,16-distanna[5.5]ferrocenophane

“…In recent years, the host-guest chemistry of anion recognition has become a topic of increasing interest (Pierre & Baret, 1983;Dietrich, 1993;Schmidtchen & Berger, 1997). For some time we have been interested in the synthesis of tin-and silicon-containing multidentate Lewis acids for anion complexation (Altmann et al, 1997). Some of our compounds were shown to function [Fe2Sn2 (CgHlsSi)4] as carriers in phosphate-sensitive electrodes (Chaniotakis et al,, 1993;Tsagatakis et al, 1994).…”

Phosphinimine complex of organotin(IV) compounds stabilized by O,C,O-chelating ligand

“…An interestingly, the fact that the 31 P{ 1 H} NMR spectrum of compounds 4 and 5 revealed 2 J( 31 P, 119 Sn) at room temperature suggests that both complexes are kinetically inert and it contrasts with organotin(IV) complexes of HMPA. The later complexes are kinetically more labile and similar 2 J( 31 P, 119 Sn) couplings were observed at low temperature only [14] suggesting that the R 3 P]NH group is a stronger ligand towards R 3 SnCl moiety in comparison to HMPA. Single crystals of 4 suitable for X-ray diffraction analysis were obtained by crystallization from toluene/hexane solution at þ4 C. The molecular structure of 4, selected bond lengths, and angles are shown in Fig.…”

“…Compound 3 can be described as aminophosphonium salt with PeN single bond and positive charge on phosphorus atom (see supporting information, Scheme S1A) or as phosphiniminium salt where P]N double bond contains positive charge on nitrogen atom (Scheme S1B). The P1eN1 (1.6314 (14) A) bond length is shorter that PeN single bond predicted by Pyykkö (S cov (P,N) ¼ 1.82 A) [10] and proved the existence of P]N double bond in 3 (for double bond covalent radii S cov (P,N) ¼ 1.62 A) [10]. The phosphiniminium form P]NH 2 in 3 is further stabilized by the O,C,O-chelating ligand L 1 , due to the existence an NeH/O hydrogen bonding [O2/N1 2.7387 (19) A] with one of the oxygen atom of ligand L 1 .…”

[cyclo-CH2{Sn(Cl2)CH2Si(Me2)}2O]: Synthesis and Complexation Behaviour of a Novel, Cyclic, Bidentate Lewis Acid and Its Conversion into a Tin-Containing Fluorosilane with Intermolecular Si−F⋅⋅⋅Sn Bridges

“…One possibility to overcome this disadvantage might be to make the Cl 2 SnCH 2 SnCl 2 ‐fragment part of a polymer. In continuation of our studies on tin‐based bidentate16, 22–27, 29 and multidentate28 Lewis acids we report here on the synthesis and structure of a novel cyclic eight‐membered ditin compound containing a siloxane unit and on its complexation behaviour towards chloride27 and fluoride56 ions. Also presented are attempts at ring‐opening reactions of this eight‐membered ring and its perphenylated derivative leading, however, to a novel tin‐containing fluorosilane.…”