Some bis-π-cyclopentadienylmolybdenum amino-acid derivatives and related compounds

Abstract

The amino-acid complexes [Mo(π-C₅H₅)₂(NH₂R^1·CHR^2·CO₂)]⁺X^–(X = Cl or PF₆) are described; the amino-acid residues are derived from glycine, alanine, phenylalanine, valine, leucine, isoleucine, proline, methionine, sarcosine, and N-methylalanine, and are bound to the molybdenum by oxygen and nitrogen. Cysteine forms the two derivatives [Mo(π-C₅H₅)₂NH₂·CH(CO₂H)·CH₂S]⁺X^– and [{Mo(π-C₅H₅)₂NH₂·CH(CO₂)·CH₂S}₂H]⁺ PF₆^– and is bound to the metal by sulphur and nitrogen. The α-C hydrogen atoms of all the complexes except that with proline, readily exchange with ²H₂O in mild base. Factors affecting the α-CH labilisation are discussed. The exchange properties of related complexes [Mo(π-C₅H₅)₂(O₂C·CH₂S)], and [Mo(π-C₅H₅)₂(NH₂·CH₂·CH₂·-NH₂)]²⁺X₂^2– have been determined.