Amidation of aldehydes using mono-cationic half-sandwich rhodium(III) complexes with functionalized phenylhydrazone ligands

Publication date: Available online 26 February 2019Source: Journal of Organometallic ChemistryAuthor(s): Neelakandan Devika, Subbiah Ananthalakshmi, Nandhagopal Raja, Gajendra Gupta, Bruno TherrienAbstractA series of mono-cationic half-sandwich rhodium(III) complexes have been synthesized in methanol using phenylhydrazone-derived ligands (L1–L6) and the starting precursor [(η5-C5Me5)2Rh2(μ-Cl)2Cl2] in a 2:1 molar ratio. The N,N′-phenylhydrazone complexes have been isolated as tetraphenylborate salts. All complexes were characterized by elemental analysis, FT-IR, UV-visible, NMR spectroscopy and mass spectrometry. The molecular structure of complex [(η5-C5Me5)Rh(L1)Cl](BPh4) (1) was confirmed by single-crystal X-ray structure analysis. Complex [(η5-C5Me5)Rh(L3)Cl](BPh4) (3) was used as an efficient catalyst for the amide formation reaction, with up to 99% conversion after 2 h in toluene at 110 °C in the presence of hydroxyl amine hydrochloride and sodium bicarbonate.

Source: Journal of Organometallic Chemistry - February 26, 2019 Category: Chemistry Source Type: research