Pre-lab 4.1 Substitution Properties of Metal Ion Complexes in

Pre-lab 4.1 Substitution Properties of Metal Ion Complexes in Aqueous Solution4,5 

The preparation of substituted pentacyanoferrate(II) ion complexes involves a series of ligand exchange reactions at the iron(II) metal center. Equations (4.1)-(4.3) outline the synthesis of amino acid (AA) metal complexes in aqueous solution. Starting from sodium nitroprusside ion, [Fe(CN)5(NO)]2, equation (4.1), the nitrosyl ligand, NO+, is replaced by an ammine moiety, NH3. The aquapentacyanoferrate(II) ion, [Fe(CN)5(H20)]3, is then generated in situ, equation (4.2), followed by reaction with an AA to yield the desired [Fe(CN)5(AA)](3+n) complex, equation (4.3). 

TABLE 4.1 CFAE Calculations for High-Spin (hs) and Low-Spin (Is) Otahedral Substitution Reactions (values from Basolo and Johnson4) 

Electron Configuration CFSE, A Octahedral CFSE, A Sq pyr CFAE, SA Predicted Behavior 

Procedure 4.1 Synthesis of Sodium Amminepentacyanoferrate(ll), Na3[Fe(CN)5(NH3)]-3 H20 from Sodium Nitroprusside, Na2[Fe(CN)5(N0)]-2H20 

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