Synthetic,Spectroscopic and Structural Studies of the Rhenium(I) Dicarbonyl Complexes of Phosphite,Phosphonite, and Phosphinite Ligands: cis,mer‐[ReBr(CO)2{PPh3‐n(OR)n}3] (R = Me,Et; n = 1—3)

The reaction of ReBr(CO)₅] with phosphite and phosphonite ligands in toluene yielded cis, mer‐ReBr(CO)₂L₃] ( 2 : L = P(OMe)₃ 2a : P(OEt)₃ 2b : PPh(OMe)₂ 2c : PPh(OEt)₂ 2d ). Compounds 2c and 2d were also obtained, as were the phosphinite complexes 2e L = PPh₂(OMe)] and 2f L = PPh₂(OEt)], by reaction of the corresponding phosphorus ligand with trans, mer‐ReBr(CO)₃L₂]. Compounds 2 were all characterized by elemental analysis, mass spectrometry and NMR spectroscopy, and the structures of 2b , 2c and 2d were determined by X‐ray diffractometry. Compounds 2a‐d are stable in chloroform and dichloromethane, but 2e and 2f are transformed into the corresponding trans, mer‐ReBr(CO)₃L₂] complexes by a reaction for which a partial mechanism is put forward.