Chiral-at-Metal Compounds [CpFe(Prophos)L] (L = Cl, I, CN), [CpFe(Prophos)CO]X (X = I, PF6), and [IndFe(Prophos)CO]I

The compounds [CpFe(Prophos)Cl] and [CpFe(Prophos)I] were prepared in photochemical reactions of [CpFe(CO)2Cl] and [CpFe(CO)2I] with (R)-Prophos. They consist of pairs of RFe,RC and SFe,RC diastereomers which only differ in the configuration at the metal atom. The diastereomerically pure compounds (SFe,RC)-[CpFe(Prophos)Cl] and (RFe,RC)-[CpFe(Prophos)I], which have the same relative configurations, were isolated. They epimerize via change of the Fe configuration and approach the equilibria (RFe,RC)-/(SFe,RC)-[CpFe(Prophos)Cl] = 5/95 and (RFe,RC)-/(SFe,RC)-[CpFe(Prophos)I] = 95/5 in first-order reactions with half-lives of 43 min at 20 °C and 50 min at 50 °C in C6D6, respectively. The reaction of (RFe,RC)-/(SFe,RC)-[CpFe(Prophos)I] = 95/5 with KCN afforded the cyano complex [CpFe(Prophos)CN] in the diastereomer ratio RFe,RC/SFe,RC = 50/50. Both diastereomers (RFe,RC)- and (SFe,RC)-[CpFe(Prophos)CN] could be isolated diastereomerically pure. The compounds (RFe,RC)- and (SFe,RC)-[CpFe(Prophos)CN] are configurationally stable at the metal center. There is no diastereomer interconversion, not even at higher temperatures. The carbonyl complexes [CpFe(Prophos)CO]I, [CpFe(Prophos)CO]PF6, and [IndFe(Prophos)CO]I were prepared in thermal reactions of [CpFe(CO)2I] and [IndFe(CO2)I] with (R)-Prophos or in an autoclave reaction of [CpFe(Prophos)I]/NH4PF6 with CO under pressure. All the carbonyl complexes are configurationally stable at the metal center. Seven diastereomers were characterized by X-ray crystallography. Including the two diastereomers (RFe,RC)-[CpRu(Prophos)Br] and (RFe,RC)-[CpRu(Prophos)I], a conformational analysis of the M-Prophos chelate ring was carried out, resulting in characteristic differences between major and minor diastereomers.