Iron(II) Triflate Salts as Convenient Substitutes for Perchlorate Salts:  Crystal Structures of Fe(H2O)6(CF3SO3)2and Fe(MeCN)4(CF3SO3)2

The most convenient source of anhydrous iron(II) triflate is the acetonitrile solvate isolated from the reaction of finely divided iron metal with triflic acid in acetonitrile. The cyrstalline Fe(MeCN)4(OTf)2 readily loses two MeCN molecules under vacuum to afford Fe(OTf)2·2MeCN, which is stable to air oxidation but absorbs water. Crystals of the hexahydrate containing a hydrogen-bonded, layered structure are obtained from water.