Bromidocarbonyl{(1S,2S)-N-[2-(dicyclohexylphosphanyl)ethylidenyl]-N′-[2-(diphenylphosphanyl)ethyl]-1,2-diphenylethane-1,2-diamine}iron(II) tetraphenylborate

Abstract

In the title compound, trans-(S,S)-[FeBr(CO)(PPh 2 CH 2 CH 2 NHCHPhCHPhN-CHCH 2 PCy 2 )]BPh 4 , the Fe II ion is in a distorted octahedral complex geometry with a cis-ligand geometry in which two diastereomers co-crystallized in the asymmetric unit. These diastereomers differ by the orientation of the N-H moieties on the ligand; one is in the S conformation (A), and the other R (B). Diasteromer A has a P-Fe-P angle of 104.36 (6) and B has a P-Fe-P angle of 102.70 (6) . During the refinement of the structure, electron density peaks were located that were believed to be highly disordered solvent molecules (possibly diethyl ether). Attempts made to model the solvent molecule were not successful. The SQUEEZE [Spek (2015). Acta Cryst. C71, 9-18] option in PLATON indicated there was a large solvent cavity of 363 Å 3 . In the final cycles of refinement, this contribution of 117 electrons to the electron density was removed from the observed data. The density, the F(000) value, the molecular weight and the formula are given without taking into account the results obtained with SQUEEZE. Structure descriptionThis is the first time our group has observed that our P-N-NH-P ligands adopt a cisligand geometry on the iron(II) center. The initial report of this complex (Smith & Morris, 2015) had assumed that there was a mer-geometry of the tetradentate ligand; however, it was not until after the article had been published that crystals were obtained for X-ray diffraction study. This complex has been applied in the catalytic asymmetric

Iron Catalysis in Reduction and Hydrometalation Reactions

“…C61 was successfully evaluated in asymmetric TH of ketones with 38–99% ee and TON up to 4300. In comparison with the parent complexes C39 , C59 , and C60 , C61 exhibited better enantioselectivities but lower activities. , Interestingly, C61 crystallized in the cis -β configuration with the more flexible ethyldiphenylphosphino group in the apical position . With this structural information in mind, Morris then developed two families of new cis -β iron­(II) PNNP′’ complexes with an orthophenylene arm: one with an amino–imino bridge ( C62 ) and the other one with a bisamino bridge ( C63 ).…”