Arylimido-hydrido complexes of rhenium, Re(PPh 3) 2(NAr)(H)Cl 2 and Re(PPh 3) 2(NAr)(OR)(H)Cl

Abstract

By reaction of Re(PPh 3) 2(NAr)(H)Cl 3 (Ar = C 6H 4Me p, A) with sodium isopropanolate in isopropanol, the arylimido-hydrido complex, Re(PPh 3) 2(NAr)(H)Cl 2 (1a) has been obtained. Compound (1a) as well as the corresponding (1b) (Ar = C 6H 4OMe- p) was also obtained using zinc oxide instead of sodium isopropanolate. When compound (A) was reacted with zinc oxide or with triethylamine in ethanol, the arylimido-ethoxohydrido derivative, Re(PPh 3) 2(NC 6H 4Me- p)(OEt)(H)Cl (2) was isolated, compound (1a) being the intermediate. When the latter reaction was carried out in C 2D 5OD, the corresponding deuterated complex, Re(PPh 3) 2(NC 6H 4Me- p)(OC 2D 5)(D)Cl, was obtained. When CH 3OH or CD 3OD were used as the reaction media, the complexes Re(PPh 3) 2(NAr)(OCH 3)Cl 2 (3) and Re(PPh 3) 2(NAr)(OCD 3)Cl 2 (4) (Ar = C 6H 4Me- p) were respectively formed. The hydrido-methoxo complex, Re(PPh 3) 2(NC 6H 4Me- p)(H)(OCH 3)Cl (5), was indirectly obtained by reacting (1a) with zinc oxide in methanol. Compound (2) reacts with KCl or HCl leading to (1a). When in solution, compound (2) undergoes a reductive elimination reaction, ethanol being released, while the fate of the rhenium moiety has not been yet clarified. By reaction of (1a) with chlorine, the starting arylimido complex (A) was obtained.