o-Bis(haloorganostannyl)benzenes As Powerful Bidentate Lewis Acids toward Halide Ions

Abstract

The synthesis of the o-phenylene-bridged ditin species o-C 6 H 4 (SnXMe 2 ) 2 (2, X ) Cl; 4, X ) F) and o-C 6 H 4 (SnCl 2 Me) 2 (3) is reported and the crystal structures of [o-C 6 H 4 (SnClMe 2 ) 2 ‚ Cl] -[(Ph 3 N) 2 P] + (5) and [o-C 6 H 4 (SnClMe 2 ) 2 ‚F] -[K‚C 20 H 24 O 6 ] + (7) are described. Variabletemperature 119 Sn and 19 F NMR studies indicate that 2 and 4 act as bidentate Lewis acids toward chloride and fluoride ions exclusively forming the stable anionic 1:1 complexes 5, 7, and [o-C 6 H 4 (SnFMe 2 ) 2 ‚F] -[Et 4 N] + ( 8). No formation of dianionic 1:2 adducts was observed even with excess of halide ions. The affinity of 2 toward fluoride is greater than toward chloride. Reaction of 2 with HMPA gives the neutral complex o-C 6 H 4 (SnClMe 2 ) 2 ‚(Me 2 N) 3 PO (10), the crystal structure of which is also described.

X-Ray Structure of a Heterochiral, Sulfoximine-Stabilized Dilithiomethane Derivative

“…The a,o-dilithiated intermediates known for structurally related sulfones and sulfoximines mimic the reactivity of an a,a-dianion in trapping reactions with electrophiles. [8] This is also the case for the so called 1151 ± 1152. [15] The solution host ± guest properties of 1 have been recently reported:…”

“…[8,10] Such reagents might induce two consecutive C À C bond formations in a stereoselective manner. Here we present the first experimental proof for such a chiral dilithiomethane derivative with the X-ray structure of an a,a-dilithiated sulfoximine.…”

“…[7,8] To date, this solubilization effect is believed to be uniquely related to the structurally perfect, yet tedious to prepare, dendrimers. The compact dendrimer topology is promising for controlled release [9] and confined chemical nanoreactors.…”

Bis[di‐n‐alkyl(fluoro)stannyl]methanes, (R2FSn)2CH2 (R = n‐octyl, n‐dodecyl): Stable Fluoride‐Selective Carriers

“…After removing the solvent, the remaining residue was washed with dichloromethane (20 mL), filtered and dried in vacuo to give 2.3 g (60%) of compound 3. 1 …”

“…As shown, mainly by variable-temperature NMR spectroscopy and single-crystal X-ray diffraction analysis, open-chain as well as cyclic bis(haloorganostannyl)alkanes function as bicentric Lewis acids towards Lewis bases such as fluoride and chloride ions [1Ϫ7] . The methylene-, dimethylene-and ophenylene-bridged ditin derivatives [Ph 2 (X)Sn] 2 CH 2 , [3] Ph 2 XSnCH 2 CH 2 SnXPh 2 , [4] and o-C 6 H 4 (SnXMe 2 ) 2 [1] (X ϭ F, Cl), respectively, preferably chelate fluoride over chloride ions.…”