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

The solvento calcium bromide CaBr2(DME) has been prepared by reacting anhydrous calcium acetate with acetyl bromide in dimethoxyethane (DME), while refluxing a suspension of CaCl2 in DME/SOCl2 gave CaCl2(DME), high yields being secured in both cases. Crystals of the ionic [CaBr(DME)2(H2O)2]Br (1), were shown to contain heptacoordinated calcium(II) with bidentate DME. Two polymorphs of the mononuclear, CaBr2(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 CaBr2(DME). Coordinated DME in CaX2(DME) was found to be substituted by nitrogen bases in toluene, the adducts CaX2py2 (X = Cl, Br), CaBr2(DMEDA)2, (DMEDA = N,N′-dimethylethylenediammine) and CaBr2(L–L–L) [L–L–L = 2,6-bis(3,5-dimethyl-N-pyrazolyl)pyridine)] being obtained in good yields.