Metal complexes of biologically important ligands -: XCVII.: Synthesis and characterisation of cyclometallated compounds of Schiff bases from α-amino acid esters with manganese(I) and rhenium(I) carbonyls

N-Diphenylmethylen Schiff bases from alpha-amino acid esters react with MnMe(CO)(5) and ReMe(CO)(5) in refluxing octane to give the orthometallated complexes (CO)(4)M[{C6H4(C6H5)C=(NCHRCO2R2)-C-1}-C,N] (M=Mn, Re). Reactions of the orthometallated rhenium complexes with HBF4 afford ionic N,O-chelate complexes under cleavage of the Re-C bond. The structures of the valine derivatives of the orthomanganated and -rhenated complexes were determined by X-ray diffraction. (C) 1998 Elsevier Science S.A.