Abstract
New mono‐ and dicarbonyl phosphane Re^I^ complexes [ReCl(L)~2~(CO)(PPh~3~)~2~] {L = 3,5‐Me~2~‐Hpz (3), quin (4)} and [Re(L)~n~(CO)~2~(PPh~3~)~2~][BPh~4~]~m~ {L = pz/Hpz, n = 2, m = 0 (2); L = 4,7‐Ph~2~‐phen, n = 1, m = 1 (5); L = 2‐Me‐dipic, n = 1, m = 0 (6)} were prepared by reaction of the dinitrogen Re^I^ precursor [ReCl(N~2~)(CO)~2~(PPh~3~)~2~] (1), in refluxing methanol or methanol/benzene mixture, with 3,5‐dimethylpyrazole (3,5‐Me~2~‐Hpz), quinoline (quin), pyrazole (Hpz), 4,7‐diphenyl‐1,10‐phenanthroline (4,7‐Ph~2~‐phen) and dipicolinic acid (H~2~dipic), respectively, with esterification of the latter in 6 to afford the 2‐methoxycarbonyl‐6‐pyridinecarboxylate (2‐Me‐dipic) moiety. Complexes 2–6 were characterized by IR spectroscopy, ^1^H‐, ^31^P{^1^H}‐ and ^13^C{^1^H} NMR spectroscopy, FAB‐MS, cyclic voltammetry, elemental analyses and single‐crystal X‐ray diffraction (for 2, 5 and 6) analyses which indicate mutually trans triphenylphosphane ligands. The redox behaviour of the obtained complexes in solution was studied, and the Lever electrochemical ligand parameter E~L~ was determined, for the first time, for 4,7‐Ph~2~‐phen. Compounds 2–6 represent the first examples of mono‐ and dicarbonyl Re complexes bearing these types of ligands.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)