Magnesiate Ions in Solutions and Solids Prepared from Dialkylmagnesium Compounds and Cryptands

Article abstract of DOI:10.1021/ja00288a026

Addition of 2,1,1-cryptand to diethylmagnesium solutions greatly speeds reactions with pyridine and leads to formation of significant amounts of a 1,4- as well as a 1,2-addition product, observations attributed to formation of magnesiate species.In crystalline +(2,2,1-cryptand)>2Et6Mg2^2-, the magnesiums of the dianion are identical and have essentially a tetrahedral bonding geometry.They share two bridging ethyl groups.The magnesium of the cation is bonded to five of the heteroatoms of the cryptand and to the ethyl group.In crystalline NpMg⁺(2,1,1-cryptand)Np3Mg^-, the magnesium of he anion has a trigonal planar bonding geometry.The coordination geometry of the magnesium of the cation is essentially that of a pentagonal bipyramid with bonds to all six of the heteroatoms of the cryptand and a bond to the neopentyl group.The 1H NMR spectrum of a benzene solution of this solid is consistent with the presence of the same ions in the solution.