Preparation of the chiral amine salts [(η5-C5H5)Ru(PPh3)(CNtBu)(NH2R)]PF6, RNH2 = α-methylbenzylamine, 1-cyclohexylethylamine, and 1-(1-naphthyl)ethylamine: X-ray single crystal structures of the diastereomeric salts (SRuRC)- and (RRuRC)-[(η5-C5H5)Ru(PPh3

Diastereomeric salts [(η5-C5H5)Ru(PPh3)(CNtBu)(NH2R)]PF6 containing both a chiral metal centre and an α-chiral amine ligand have been prepared. The use of diamagnetic anisotropy in their 1H NMR spectra to distinguish the diastereomers has been supported by single crystal X-ray crystallography. The structures of the salts containing the ligands cyclohexylamine and α-methylbenzylamine (both diastereomers) have been determined at low temperature. Decomplexation of the amine ligand from purified diastereomeric salts to affect resolution of the metal centred chirality has been attempted. The chiral isonitrile ligand containing compounds [(η5-C5H5)Ru(PPh3)(CNCH(Me)Ph)(Cl)] and [(η5-C5H5)Ru(PPh3)(CNCH(Me)Ph)(NH3)]PF6 have been prepared from (S)-α-methylbenzylisonitrile and the single crystal X-ray structure of both diastereomeric salts of the ammine compound has been determined.

Graphical abstractThe structure of diastereomeric salts containing a chiral amine and a metal centre has been investigated by single crystal X-ray crystallography and by observing diamagnetic anisotropy effects in NMR spectroscopy. Attempts to remove the amine ligand to produce homochiral at metal products are reported.Figure optionsDownload full-size imageDownload as PowerPoint slide