Tetrakis carboxylato dihalodirhenium III Compounds

The melt is allowed to cool. It may then be handled in air. The excess of acid is extracted with diethyl ether. For those products which are soluble in chloroform (see Table I) recrystallization is carried out using this solvent and the product dried in vacuum at 100° for 12 hours. The yields vary from 70 to 90% based on Re2(02CCH3)4X2. 

The orange Re2(02CCH3)4Cl2 and brown Re2(02CCH3)4Br2 are air-stable and practically insoluble in common solvents. The properties of some arylcarboxylato compounds are summarized in Table I. 

These compounds have been obtained by only one general route, viz., by the interaction of carboxylic acids with molybde- Temple University, Philadelphia, Pa. 19122. 

The compounds are all yellow to orange in color. They vary in stability and sensitivity to air. The acetate is a yellow solid which is practically insoluble in all common solvents. It slowly decomposes (turning green and finally dark blue) over a period of days to weeks at room temperature. Decomposition occurs even in an inert atmosphere and does not appear to be appreciably faster in dry air. 

The arylcarboxylato compounds are more soluble, e.g., in CHCls and acetone, but the solutions are extremely air-sensitive. Except for the benzoate they are all very air-sensitive even as solids and must be handled entirely under nitrogen. 

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