Iron(Ⅱ) iodide was reacted with carbon monoxide in tetrahydrofuran solution at room temperature, then N,N-bis(diphenylphosphino)amino- acid methylester was added to yield trans-iron carbonyl complexes trans-Fe(CO)~2I~2[RCHN(PPh~2)~2CO~2CH~3](R=H, a; R=CH~3, b; r=PhCH~2, c) which are stable in solid state. The complex a was characterized by X-ray analysis. It belongs to the orthorhombic space group Pna2~1 with a=1.7399(8) nm, b=3.0201(14) nm, c=1.7919(8) nm, α=β=γ=90°, V=9.416(7) nm^3, Z=2, D~c~a~l~c=1.742m /mm^3, F(000)=4800. The X-ray structure of complex a reveals that geometry around the iron can be considered as octahedral. This method provides an easy way to label biological molecules with transition-metal carbonyl fragments.

Key words: CARBONYL COMPOUNDS, IRON COMPLEX, AMINO ACID, LABELLED COMPOUNDS, X-RAY DIFFRACTION ANALYSIS, CRYSTAL STRUCTURE