Cyrhetrenylimines and cyrhetrenylamines: Synthesis, characterization and X-ray crystal structure

Cyrhetrenyl Schiff base derivatives of the form (η5-C5H4CHNAr)Re(CO)3, [Ar = Ph (1a) C6H4OMe-p (1b) and C6H4NO2-p (1c)] have been prepared from cyrhetrenylcarbaldehyde and the corresponding aromatic amines. 1H and 13C NMR indicates that these compounds have the anti-(E) conformation in solution and the X-ray crystal structure of 1b confirms that it also adopts the anti-(E) form in the solid state. Further reaction of cyrhetrenylaldimines 1 with sodium borohydride in methanol produces quantitatively, the corresponding amine derivatives (η5-C5H4CH2–NHAr)Re(CO)3 [Ar = Ph (2a) C6H4OMe-p (2b) and C6H4NO2-p (2c)]. All these cyrhetrenylamines were characterized by IR, 1H and 13C NMR, MS. Additionally, 2b has been characterized structurally.

Graphical abstractNew cyrhetrenylimine complexes 1a–c have been synthesized and fully characterized. They exist as the anti-(E) conformation in solution and in solid state (1b). Reduction of 1a–c with NaBH4 produces quantitatively the corresponding cyrhetrenylamine derivatives 2a–c.Figure optionsDownload full-size imageDownload as PowerPoint slide