Axially asymmetric metal alkyls. Part 2. Synthesis of the di-Grignard reagent [{Mg(thf)nCl}2R] [thf = tetrahydrofuran, R = (2-CH2C6H4)22-] and 6,7-dihydro-5H-dibenzo[c,e]-silepines and -stannepines; X-ray crystal structures of [SnPh2R] and δ-SS- and λ-RR-[SnPh2{[2-CH(SiMe3)C6H 4]2}]and λ-RR-[SnPh2{[2-CH(SiMe3)C6H 4]2}]: and λ-RR-[SnPh2{[2-CH(SiMe3)C6H 4]2}]

Lutz M. Engelhardt, Wing Por Leung, Colin L. Raston, Paul Twiss, Allan H. White

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Reactions of Mg and Li with 2,2′-bis(chloromethyl)biphenyl in tetrahydrofuran (thf) yield respectively a new di-Grignard reagent, [{Mg(thf)nCl}2{(2-CH2C6H 4)2}] (5), for rather critical conditions, and the intramolecular cyclization product, 9,10-dihydrophenanthrene which further reacts to form a radical anion (g = 2.0037, hydrogen hyperfine coupling unresolved). Substituted 6,7-dihydro-5H-dibenzo[c,e]-silepines and -stannepines derived from (5) and the dilithium complexes [{Li(tmen)}2{(2-CHRC6H4)2}] (R = H or SiMe3; tmen = NNN′N′-tetramethylethylenediamine) are also reported. The crystal structures of the compounds [SnPh2{(2-CHRC6H4)2}] [R = H (8) or SiMe3 (9)] have been determined. Sn-C (aromatic) distances are similar [2.139(8) and 2.149(9) Å in (8), cf. 2.136(4) Å in (9)] whereas the Sn-CHR distances are significantly different [2.157(8) and 2.159(9) Å in (8), cf. 2.184(4) Å in (9)]; the angles subtended by the bidentate ligands are 98.7(3)° in (8) and 99.4(2)° in (9) and the associated torsion angles along the biphenyl axis are respectively 66.0 and 70.8°. Compound (9) comprises a racemate of δ-SS and λ-RR isomers, in the solid, with the molecules lying on C2 axes.

Original languageEnglish
Pages (from-to)331-340
Number of pages10
JournalJournal of the Chemical Society, Dalton Transactions
Issue number3
DOIs
Publication statusPublished - Mar 1984
Externally publishedYes

Fingerprint Dive into the research topics of 'Axially asymmetric metal alkyls. Part 2. Synthesis of the di-Grignard reagent [{Mg(thf)<sub>n</sub>Cl}<sub>2</sub>R] [thf = tetrahydrofuran, R = (2-CH<sub>2</sub>C<sub>6</sub>H<sub>4</sub>)<sub>2</sub><sup>2-</sup>] and 6,7-dihydro-5H-dibenzo[c,e]-silepines and -stannepines; X-ray crystal structures of [SnPh<sub>2</sub>R] and δ-SS- and λ-RR-[SnPh<sub>2</sub>{[2-CH(SiMe<sub>3</sub>)C<sub>6</sub>H <sub>4</sub>]<sub>2</sub>}]and λ-RR-[SnPh<sub>2</sub>{[2-CH(SiMe<sub>3</sub>)C<sub>6</sub>H <sub>4</sub>]<sub>2</sub>}]: and λ-RR-[SnPh2{[2-CH(SiMe3)C6H 4]2}]'. Together they form a unique fingerprint.

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