Cooperative Effect of a Classical and a Weak Hydrogen Bond for the Metal-Induced Construction of a Self-Assembled β-Turn Mimic
作者:Andy C. Laungani、Manfred Keller、John M. Slattery、Ingo Krossing、Bernhard Breit
DOI:10.1002/chem.200900662
日期:2009.10.12
means of unprecedented multiple noncovalent interactions (classical hydrogenbond, weakhydrogenbond, metal coordination, π‐stacking interaction) was developed and investigated. Our results address the importance and capability of weakhydrogen bonds (WHBs) as important attractive interactions in self‐assembling processes based on molecularrecognition. Together with a classical hydrogenbond, WHBs may
Water Soluble Cationic Phosphine Ligands Containing <i>m</i>-Guanidinium Phenyl Moieties. Syntheses and Applications in Aqueous Heck Type Reactions
作者:Antonella Hessler、Othmar Stelzer、Harald Dibowski、Karin Worm、Franz P. Schmidtchen
DOI:10.1021/jo961140n
日期:1997.4.1
Cationicphosphineligandscontaining m-guanidinium phenyl substituents Ph(3-n)P[C(6)H(4)-m-NHC(NH(2))(NMe(2))](n)}(n+) nCl(-) (n = 1-3) (17a-c) have been obtained by addition of dimethylcyanamide to the amino groups of tertiary (m-aminophenyl)phosphines in acidic medium. The tertiary (m-aminophenyl)phosphines Ph(3-n)P(C(6)H(4)-m-NH(2))(n) (4a-c) were prepared by reaction of (3-[N,N-bis(trimethyl
Ionic Interaction as a Powerful Driving Force for the Formation of Heterobidentate Assembly Ligands
作者:Henrik Gulyás、Jordi Benet-Buchholz、Eduardo C. Escudero-Adan、Zoraida Freixa、Piet W. N. M. van Leeuwen
DOI:10.1002/chem.200601640
日期:2007.4.16
An ionicinteraction has been used for the first time to assemble monophosphane ligands. NMR spectroscopy and X-ray studies show that cationic and anionic triphenylphosphane derivatives form ion pairs and subsequently act as a ligand in various transition-metal complexes. The position of the ionic functional groups allows both cis and trans coordination of the novel assemblyligand in square-planar
Catalysis by Design: Wide-Bite-Angle Diphosphines by Assembly of Ditopic Ligands for Selective Rhodium-Catalyzed Hydroformylation
作者:David Rivillo、Henrik Gulyás、Jordi Benet-Buchholz、Eduardo C. Escudero-Adán、Zoraida Freixa、Piet W. N. M. van Leeuwen
DOI:10.1002/anie.200701255
日期:2007.9.24
Enantioselective Supramolecular Catalysis Induced by Remote Chiral Diols
作者:Piet W. N. M. van Leeuwen、David Rivillo、Matthieu Raynal、Zoraida Freixa
DOI:10.1021/ja207912d
日期:2011.11.23
A new method of creating libraries of chiral diphosphines is presented. Supramolecular coordination compounds based on Ti, Rh, achiral ditopic ligands, and chiral diols were synthesized by in situ mixing and used as catalysts in the asymmetric hydrogenation of (Z)-methyl 2-acetamido-3-phenylacrylate, giving ee's of up to 92%. The ditopic ligands contain a Schiff base that coordinates to the assembly metal Ti and a phosphine as a ligand for Rh. Chirality is introduced by coordination of the chiral diols to Ti. The controlling chiral center and the substrate are separated by as much as 13 angstrom.