EXTRACTION OP MANGANESE(II) BT MIXTURES OP DIDODECYLNAPHTHALENESOLFONIC ACID AND r-BUTYL- CYCLOHEXANO-15-CROWN-5: SPECTRAL EVIDENCE FOR THE FORMATION OF A MANGANESE(II) - CROWN ETHER COMPLEX

Addition of t-butylcyclohexano-15-crown-5 (tBC-15C5) induces a synergistic effect in the extraction of Mn²⁺ ion with didodecylnaphthalenesulfonic acid (HDDNS). This synergism is the result of the inner-sphere complexation of the crown ether to the manganese(II) ion. The formation of this complex, first suggested by distribution studies, has been confirmed by FTIR experiments. The C-O-C stretching bands for the crown ether ligand shift to lower frequency when Mn²⁺ ion is extracted into a CC14 solution of HDDNS and tBC15C5. A similar C-O-C Btretching band is observed for the crystalline complex [Mn(15C5 ) (Bu₃CS0₃)₂] (where 15C5 = 15-crown-5 and Bu = n-butyl).Formation of analogous complexes is not observed for Fe³⁺, co²⁺,N²⁺,cu²⁺, or zn²⁺ under similar conditions.