Synthesis and characterization of new formamidino-complexes of rhenium(I). The crystal structure of [Re(CO)2(p-NO2C6H4N−CH−O)(PPh3)2]

The compound [Re(CO)3(PPh3)2Cl] reacts with Li(OCHNAr) (Ar = C6H5, p-CH3C6H4, p-ClC6H4, p-CH3OC6H4, p-NO2C6H4, o-CH3C6H4) in boiling tetrahydrofuran or toluene to yield new complexes of ReI of the type [Re(CO)2(ArNCH O)(PPh3)2]. The IR spectra suggest that the ligand is chelated and that the two CO groups are in cis positions. The crystal structure of the tittle compound was determined by X-ray analysis using counter data. The compound crystallizes in the triclinic system, space group P1, with a = 10.26(1), b = 12.91(1), c = 16.73(1) Å, α = 111.27(3)°, λ = 75.78(3)°, and γ = 107.12(3)° for Z = 2. The structure was refined to R = 0.049. The rhenium atom is in a distorted octahedral co-ordination with two aixal PPh3, two cis-CO groups, and the bidentate ligand forming a four-membered ring with the metal. © 1983.