Synthesis and characterization of iron(2+) and ruthenium(2+) diimino-, diamino- and diamido-diphosphine complexes. X-ray crystal structure of trans-RuCl 2(P 2N 2C 2H 4) ∗d CHCl 3

Abstract

The interaction of Ru(OAc) 2(Ph 3P) 2 with one equivalent of N, N′-bis[ o-(diphenylphosphino)benzylidene]ethylenediamine (P 2N 2C 2) in refluxing dichloromethane gave trans-Ru(OAc) 2(P 2N 2C 2) ∗d 2H 2O ( I) in moderate yield (63%) ; in refluxing-toluene, it gave a red solid which upon recrystallization in CHCl 3 gave trans-RuCl 2(P 2N 2C 2) ∗d 2H 2O ( II) in good yield (92%). Compound II could also be prepared in good yield (85%) via the interaction of RuCl 2(DMSO) 4 with one equivalent of P 2N 2C 2 in refluxing toluene. The interaction of RuCl 2(DMSO) 4 with one equivalent of N, N′-bis[ o-(diphenylphosphino)benzylidene]-1,3-diaminopropane (P 2N 2C 3), N, N′-bis[ o-d(diphenylphosphineo)benzyl]ethylendiamine (P 2N 2C 2H 4) and N, N′-bis[ o-(diphenylphosphino)benzamido]ethane (P 2N 2C 2-amide) in refluxing toluene gave trans-RuCl 2(P 2N 2C 3) ( III), trans-RuCl 2(P 2N 2C 2H 4) ( IV) and trans-RuCl 2(P 2N 2C 2-amide) ( V) in good yield, respectively. The interaction of Fe(ClO 4) 2 ∗d 6H 2O with one equivalent of P 2N 2C 2 and P 2N 2C 2H 4 in refluxing acetonitrile gave trans-[Fe(P 2N 2C 2(CH 3CN) 2](ClO 4) 2 ( VI) and trans-[Fe(P 2N 2C 2H 4)(CH 3CN) 2](ClO 4) 2 ( VII), respectively. Interaction of FeCl 2 ∗d 4H 2O with one equivalent of N, N′-bis[ o-(diphenylphosphino)benzylidene]-1,6-diaminohexane (P 2N 2C 6) in refluxing gave trans-FeCl 2(P 2N 2C 6) ( VIII). Complexes I–VIII have been fully characterized by analytical and spectroscopic methods. The structure of IV has been established by an X-ray diffraction study. Compound II could be reduced to compound IV with NaBH 4 in ethanol and oxidized to V with aqueous H 2O 2 acetonitrile. Catalytic studies showed that both II and IV were effected catalysts for the hydrogenation of acrylic acid to propionic acid.