Intramolecularly coordinated arylmagnesium compounds: effects on the Schlenk equilibrium

• Published in: Journal of organometallic chemistry Vol. 402; no. 3; pp. 289 - 312
• Main Authors: Markies, Peter R., Altink, Rinke M., Villena, Alan, Akkerman, Otto S., Bickelhaupt, Friedrick, Smeets, Wilberth J.J., Spek, Anthony L.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 08.01.1991; Elsevier Science
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Heterocyclic compounds; Organic compounds; Physics; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; Synthesis; Enthalpy; Crystallization; Lattice parameters; NMR spectrum; X ray diffraction; Space group; Crystalline structure
• ISSN: 0022-328X; 1872-8561
• DOI: 10.1016/0022-328X(91)86244-K

A series of phenylmagnesium bromides ( 1, 3–8) with ortho-substutients capable of forming intra-molecular coordinative bonds along with the correspondng diarylmagnesium compounds ( 1a, 3a–6a, 8a) have been synthesized. The thermodynamic parameters Δ H s, and Δ S s for the Schlenk equilibria (2 ArMgBr &/rhar2; Ar 2Mg + MgBr 2) have been determined by variable temperature NMR spectroscopy. Crystal structures were obtained of 5,6,7,8,9-tetrahydrodibenz[ d,g][1,6]oxamagnesecin ( 2a) and bis(2,6-di(methoxymethyl)phenyl)magnesium ( 4a). The extent of intramolecular coordination in these compounds as determined in the solid state, is used in the discussion of the influence of substituents on the Schlenk equilibrium parameters. Unusual penta- or hexa-coordination is encountered and explained as a consequence of intramolecular coordination.