Synthesis and Structure of a New Type of Chiral Organoiron and Organoruthenium Complexes

Abstract

Abstract The synthesis of 36 [Fe(CO) 2 L 1 (η 4 ‐diene)], three [Fe(CO) 2 L 1 (η 4 ‐encne)], and five [Ru(CO) 2 L 1 (η 4 ‐diene)] complexes (L 1 = Ph 3 P, Et 3 P, (EtO) 3 P, (MeO) 3 p, C 6 H 11 NC) by thermal, selective CO ligand displacement in the corresponding tricarbonyl precursor complexes is described. In a second step, photochemical CO displacement by another phosphorus ligand L 2 leads to a new type of η 4 ‐diene complexes with a centre of chirality at the metal atom (Fe, Ru). 23 Fe and three Ru complexes of this type have been prepared and characterized. In the case of complexes with unsymmetrical dienes, racemic diastereoisomers are formed which can be separated by chromatographic methods. The molecular structures of [Fe(CO)(Ph 3 P)((MeO) 3 P)(buta‐1,3‐diene)] ( 52 ), [Fe(CO)(Ph 3 P)((MeO) 3 P)(isoprene)] ( 58 ) and [Fe(CO)(Et 3 P)(EtO) 3 P(hexa‐2,4‐dienal)] ( 62a ) were determined by X‐ray diffraction. All complexes were investigated by 13 C‐, 31 P‐ and, in part, 1 H‐NMR spectroscopy. At low temperatures, conformational isomers (rotamers) can be differentiated which probably arise from ψ rotation at the coordinated metal centre.