Activation of the CH bond in [(η5-C5H5)Fe(η5-C5H4CH2N(CH3)CH2C6H4R-4)] induced by platinum (II): Crystal structure of σ-Pt[(η5-C5H5)Fe(η5-C5H3CH2N(CH3)CH2C6H4OCH3-4)]Cl(DMSO)

Condensations of ferrocenylcarboxaldehyde (1) and p-methyl (2b) or p-chlorobenzylamines (2d) in methanol resulted in ferrocenylaldimines 3b, d which were reduced by lithium aluminum hydride to give 4b, d, respectively. Reductive methylations of 4b, d with aqueous formaldehyde, sodium cyanoborohydride and acetic acid afforded the tertiary ferrocenylamines 5b, d. Treatment of 5a–e [(η5-C5H5)Fe(η5-C5H4CH2N(CH3)CH2C6H4R-4)] (R = CH3O(a), CH3(b), H(c), Cl(d), NO2(e)) with cis-[Pt(DMSO)2Cl2] in methanol produced predominately cycloplatinated complexes 6a–eσ-Pt[(η5-C5H5)Fe(η5-C5H3CH2N(CH3)CH2C6H4-R-4)]Cl(DMSO) (R = same as before) in which the configurations consisted of RNRP and SNSP. In addition, the preferred activation of the CH bond in the cyclopentadienyl ring rather than that in the phenyl ring was also observed. All compounds 3b–5b, 3d–5d, 6a–e were characterized by elemental analysis, IR and 1H NMR. The structure of 6a was determined by X-ray single crystal diffraction. The possible mechanism for the formation of 6 was discussed.

Graphical abstractTreatment of [(η5-C5H5)Fe(η5-C5H4CH2N(CH3)CH2C6H4R-4)] 5a–e (R = CH3O(a), CH3(b), H(c), Cl(d), NO2(e)) with cis-[Pt(DMSO)2Cl2] in methanol produced predominately σ-Pt[(η5-C5H5)Fe(η5-C5H3CH2N(CH3)CH2C6H4R-4)]Cl(DMSO) 6 (R = same as before) in which the configurations consisted of RNRP and SNSP. The structure of 6a was determined by X-ray single crystal diffraction. The possible mechanism for the formation of 6 was discussed.Figure optionsDownload full-size imageDownload as PowerPoint slide