Syntheses and structural characterization of 2,4,6-trimethylaniline complexes of iron carbonyls

• 2,4,6-Trimethylaniline iron carbonyl complexes were synthesized and characterized.
• The FeN bond length is affected by basicity and steric crowding.
• Mesomeric as well as electronic effects lead to strong ligand–metal interaction.
• The complexes are water soluble and thermally stable up to their melting point.

The new 2,4,6-trimethylaniline complexes [Cp∗Fe(CO)2(NH2C6H2(CH3)3)]+ (3) and [CpFe(CO)2(NH2C6H2(CH3)3)]+ (4) (Cp∗ = η5-C5(CH3)5; Cp = η5-C5H5) have been synthesized and isolated in high yields as tetrafluoroborate salts. They have been fully characterized by NMR, IR, elemental analysis, thermogravimetric analysis and X-ray crystallography. For comparison purpose, the molecular structure of [CpFe(CO)2(NH2CH2C6H4OCH3)]+ (5) has been determined and discussed in relation to those of 3 and 4. Compounds 3 and 5 crystallize in monoclinic P21/c space group, while 4 crystallizes in triclinic P1¯ space group. Compounds 3 and 4 exhibited considerable thermal stabilities at temperatures as high as 170 °C, which is close to their melting points.

The new water soluble and stable 2,4,6-trimethylaniline complexes [Cp∗Fe(CO)2(NH2C6H2(CH3)3)]+ (3) and [CpFe(CO)2(NH2C6H2(CH3)3)]+ (4) (Cp∗ = η5-C5(CH3)5; Cp = η5-C5H5) have been synthesized and isolated in high yields as tetrafluoroborate salts. They have been fully characterized by NMR, IR, elemental analysis, thermogravimetric analysis and X-ray crystallography. The crystallographic data is compared to [CpFe(CO)2(NH2CH2C6H4OCH3)]+ (5).Figure optionsDownload as PowerPoint slide