Tetrakis acetato dirhodium II and Similar Carboxylato Compounds

TETRAKIS(ACETATO)DIRHODIUM(II) AND SIMILAR CARBOXYLATO COMPOUNDS 

Submitted by G- A. REMPEL, P. LEGZDINS, H. SMITH, and G. WILKINSON Checked by D. A. UCKOt 

The dimeric tetraacetato bridged Rh2(OCOCH3)4 has been obtained by the interaction of ammonium chlororhodate(III) or rhodium (III) hydroxide with acetic acid.1-3 Other (car-boxylato)rhodium(II) compounds were prepared directly in a similar way or from the acetate by exchange.2,3 Halo car-boxylates (RCOO, R = CC13, CF3, CH2C1, etc.) were prepared also by interaction of rhodium trichloride with the appropriate sodium salt in ethanol.4 The carboxylatcs are normally first isolated as a solvent adduct, e.g., [Rh(OCOR)2-C2H5OH]2 but are easily converted to the unsolvated complex. The acetate is readily prepared in a modification of this last procedure. A similar method is satisfactory for the preparation of other lower carboxylates as well as halo carboxylates. 

Commercial rhodium trichloride trihydrate (5.0 g.) and sodium acetate trihydrate (10.0 g.) in glacial acetic acid (100 ml.) and absolute ethanol (100 ml.) were gently refluxed under nitrogen for an hour. 

The initial red solution rapidly becomes green, and a green solid is deposited. After cooling to room temperature the green 

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