Conversion of a manganese-carbon-bonded complex to a manganese-oxygen-bonded complex, some reactions of manganese carbonato complexes

Stirring a solution of the manganese carboxylate, (dppe)(CO)(3)Mn-C(O)OCH3, 1, in dichloromethane saturated with water converts it to the bridging carbonato complex, (dppe)(CO)(3)Mn-OC(O)O-Mn(CO)(3)(dppe), 2. This multi-step con vers ion involves the in-situ transformation of a Mn-C bonded complex to a Mn-O bonded one. When 2 is stirred with HCl, it is converted quantitatively to the covalent chloride (dppe)(CO)(3)Mn-Cl, 11, with evolution of carbon dioxide. Similar HCl treatment of the manganese carboxylate 1 gives three compounds: the same covalent chloride, 11; the ionic chloride, [(dppe)(CO)(4)Mn]Cl-+(-), 12, and the hydride, (dppe)(CO)(3)Mn-H, 5. Reasonable schemes for these conversions are suggested. Heating the ionic chloride complex to its melting point converts it to the covalent chloride complex; the same transformation is accomplished by refluxing the ionic chloride in acetonitrile. (C) 1997 Elsevier Science S.A.