title: Generation and reactivity of enantiomeric (BINOLato)Ni+ complexes with chiral secondary alcohols in the gas phase.
abstract: In the presence of secondary alcohols, electrospray ionization of dilute methanolic solutions of nickel(II) salts and 1,1'-bis-2-naphthol (BINOL) leads to complexes of the formal composition [(BINOLato)Ni(CH3CH(OH)R)]+ (BINOLato refers to a singly deprotonated (R)- or (S)-1,1'-bis-2-naphthol ligand; R=CH3, C2H5, n-C3H7, n-C4H9, n-C5H11, n-C6H13, c-C6H11, and C6H5). Upon collision-induced dissociation, each mass-selected nickel complex either loses the entire secondary alcohol ligand or undergoes bond activation followed by elimination of the corresponding ketone, as revealed by deuterium labeling. When enantiomeric BINOLato ligands (R or S) are combined with chiral secondary alcohols (R or S), differences in the branching ratios between these channels for the two stereoisomers of the secondary alcohols provide insight into the chiral discrimination operative in the C--H- and O--H-bond activation processes. For saturated alkan-2-ols, the chiral discrimination is low, and if any preference is observed at all, ketone elimination from the homochiral complexes (R,R and S,S) is slightly favored. In contrast, the diastereomeric (BINOLato)Ni+ complexes of 1-phenylethanol exhibit preferential ketone losses for the heterochiral systems (S,R and R,S).
authors.affiliation: Institut für Chemie der Technischen Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin (Germany).
authors.forename: Francesca R
authors.initials: FR
authors.lastname: Novara
authors.forename: Philipp
authors.initials: P
authors.lastname: Gruene
authors.forename: Detlef
authors.initials: D
authors.lastname: Schröder
authors.forename: Helmut
authors.initials: H
authors.lastname: Schwarz
mesh_terms: D000438:Alcohols / Q000737:chemistry*; D005740:Gases; D007659:Ketones / Q000737:chemistry; D008024:Ligands; D009284:Naphthols / Q000737:chemistry*; D009532:Nickel / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D010626:Phenylethyl Alcohol / Q000737:chemistry; D013057:Spectrum Analysis
chemical_list: D000438:Alcohols; C406944:BINOL, naphthol; D005740:Gases; D007659:Ketones; D008024:Ligands; D009284:Naphthols; D009942:Organometallic Compounds; D009532:Nickel; D010626:Phenylethyl Alcohol