The synthesis and study of phosphine crown ether ligands, and an investigation of how the binding of sodium or potassium ions affects the donor ability of the phosphorus center

The phosphine crown ether, 16-(4'diphenylphosphinophenyl)-1,4,7,10,13-pentaoxa-16azacyclooctadecane (III), was synthesized using a reaction scheme beginning with n-phenyldiethanolamine and the dichloride of tetraethylene glycol, with an overall yield of 4%. Platinum and Palladium complexes of the ligand, of the form MC12L2, were synthesized as well. 13C NMR and picrate extraction data indicate III and IV (the crown-5 analog) both moderately bind sodium (14%, 15%) and potassium ions (17%, 28%). Compound V (a crown-5, triphenylphosphine-based ligand) will bind both sodium and potassium ions as well (18%, 6%). When IV is complexed to nickel carbonyl (Ni(CO)3), the addition of sodium and potassium ions cause the Al carbonyl stretching frequency to increase slightly (0.3 cm-1, 0.2 cm 1). For comparison, the addition of a proton causes the A1 carbonyl stretching frequency to increase 5.2 cm-1. However, the shift in the A1 carbonyl stretching frequency upon the addition of sodium or potassium ions indicates that ion binding by the crown ether is communicated to the phosphorus and finally to the carbonyl groups.Ball State UniversityMuncie, IN 47306