Synthesis, Molecular Structure, and Stereochemical Nonrigidity of Bis(3-(dimethylamino)propyl)difluorostannane Dihydrate, {[Me₂N(CH₂)₃]₂SnF₂·2H₂O}, and Enhanced Reactivity of Its Fluoride Adduct {[Me₂N(CH₂)₃]₂SnF₃}^-Bu₄N⁺ toward Dichloromethane

Abstract

The X-ray diffraction analysis of crystals of {[Me2N(CH2)3]2SnF2·2H2O (3a) obtained by reaction of [Me2N(CH2)3]2SnR2 (R = Me, Ph) with Pr3SnF reveals a six-coordinate, distorted octahedral geometry at tin with the pairs of fluorine, nitrogen and carbon atoms bound to the metal atom being all in a mutual trans configuration. Room-temperature 119Sn, 19F, 1H, and 13C NMR spectra of 3a reveal exchange averaging with loss of the 1 J(119Sn−19F) coupling on the 119Sn and 19F NMR time scales. Below −50 °C, 119Sn and 19F NMR coupling data evidence the existence of only two isomers among the five a priori possible ones, a major (ca. 80%) and a minor species (ca. 20%). The methyl 13C resonance as well as the 1 J(119Sn−19F), 1 J(119Sn−13C), and 2 J(19F−13C) coupling patterns reveal the major species to have the same all-trans structure as in the crystal state, while the minor species has a cis arrangement for its fluorine and nitrogen atoms and the trans one for its carbon atoms. Gradient assisted 1H−119Sn HMQC spectroscopy establishes 3 J(119Sn−1H) correlations through the Me2N→Sn bond to exist in both slow- and fast-exchange ranges. Together with the loss of the 1 J(119Sn−19F) coupling at high temperature, this evidences the Me2N→Sn coordination to be maintained during the cis−trans isomerization and the latter to occur through a dissociative mechanism involving tin−fluorine bond rupture. Addition of Bu4N+F-·3H2O in CH2Cl2 yields under quaternization of one nitrogen zwitterionic {[Me2(ClCH2)N+(CH2)3][Me2N(CH2)3]SnF3 -}·H2O (3b).

Structural study of C,N‐chelated monoorganotin(IV) halides

“…A limited number of structurally related zwitterionic organostannates has been reported. 25 Two monoorganotin(IV) compounds (1, 2) containing the 2-(dimethylaminomethyl)phenyl-group [L CN , Scheme 1(b)]…”

A DFT Study of Tin‐ and Crown‐Ether‐Based Host Molecules Capable of Binding Anions and Cations Simultaneously

“…In addition, the well-known tendency of the tin atom to involve intra-and intermolecularly bridging fluorine atoms is in line with the hardness of Sn in tin fluorides. [52] Confirmation of a preference for NϪSn interaction over SϪSn interaction was found when the possibility of complexation through the S atom of SCN Ϫ was explicitly studied. In these cases the sulfur atom was placed at the same position as the N atom in the other complexes.…”

Solid‐State Structure and Behaviour in Solution of Hypervalent Organotin(IV) Derivatives Containing 2‐(Me2NCH2)C6H4 Moieties

“…Several symmetric diorganotin(IV) dihalides containing 2-(Me 2 NCH 2 )C 6 H 4 groups [1][2][3][4][5][6][7] or related organic ligands [1,3,[8][9][10][11][12] have been investigated so far both in solution and in the solid state. Single-crystal X-ray diffraction studies have revealed that strong intramolecular NǞSn interactions are established by both nitrogen atoms of a molecular unit.…”

“…[4][5][6][7] In contrast, the related [Me 2 N(CH 2 1, B). [10,12] The use of an organic ligand with a potential for only one intramolecular NǞSn interaction resulted in trigonal bipyramidal (C,N,C)SnX 2 configurations, e.g. in RN(CH 2 CH 2 CH 2 ) 2 SnCl 2 (Scheme 1, C).…”