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.

Graphical abstractThe 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 full-size imageDownload as PowerPoint slide