Complexes of calcium halides with 1,2-dimethoxyethane (DME)

Abstract

The solvento calcium bromide CaBr 2(DME) has been prepared by reacting anhydrous calcium acetate with acetyl bromide in dimethoxyethane (DME), while refluxing a suspension of CaCl 2 in DME/SOCl 2 gave CaCl 2(DME), high yields being secured in both cases. Crystals of the ionic [CaBr(DME) 2(H 2O) 2]Br ( 1), were shown to contain heptacoordinated calcium(II) with bidentate DME. Two polymorphs of the mononuclear, CaBr 2(DME) 2(MeCOOH) ( 2), differing for their packing efficiency, have been studied by X-ray diffractometry. Compound 2 loses one DME and the coordinated acetic acid under vacuum at 30 °C, yielding CaBr 2(DME). Coordinated DME in CaX 2(DME) was found to be substituted by nitrogen bases in toluene, the adducts CaX 2py 2 (X = Cl, Br), CaBr 2(DMEDA) 2, (DMEDA = N, N′-dimethylethylenediammine) and CaBr 2(L–L–L) [L–L–L = 2,6-bis(3,5-dimethyl- N-pyrazolyl)pyridine)] being obtained in good yields.