Synthesis of Tricarbonyl Re(I) Complexes of N and P Donor Ligands

Reaction of 1,10-phenanthroline-5,6-dione V with 1,3-diphenyl propan-2-one afforded the keto-alcohol VI. Treatment of VI with alkynes, di(3-thienyl) acetylene and di(4-tert-butylphenyl) acetylene yielded 5,8-diphenyl-6,7-di(3-thienyl)-1,12-diaza-triphenylene L¹ and 6,7-di(4-tert-butylphenyl)-5,8-diphenyl-1,12-diazatriphenylene L², respectively. [ReCl(CO)₅] reacted with N^N-donor ligands L¹-L⁶ to produce fac-tricarbonylrhenium(I) complexes (20)-(25) in good yields as coloured solids. Treatment of [ReCl(CO)₅] with the bulky P^N ligand L⁷ formed the neutral complex fac-[ReCl(CO)3(L7)] (26) whilst with the azine diphosphine Z,Z-L⁸ afforded the cationic complex fac-[Re(CO)₃(E,Z-L8)]Cl (27a), where L⁸ is a tridentate ligand. The chloride anion of the complex (27a) was replaced by treating it with NH4PF6 into fac-[Re(CO)₃(E,Z-L8)]PF₆ (27b). Above complexes were characterized by a combination of elemental analysis, IR, Mass and NMR spectroscopy.