title: Spirocyclic zwitterionic lambda5Si-silicates with two bidentate ligands derived from alpha-amino acids or alpha-hydroxycarboxylic acids: synthesis, structure, and stereodynamics.
abstract: A series of zwitterionic lambda(5)Si-silicates with a (2,2,6,6-tetramethylpiperidinio)methyl group and two identical bidentate ligands derived from glycine, (S)-alanine, (S)-phenylalanine, glycolic acid, (S)-lactic acid, (S)-3-phenyllactic acid, or (S)-mandelic acid were synthesized and structurally characterized (solution and solid-state NMR spectroscopy; single-crystal X-ray diffraction). The chiral lambda(5)Si-silicates with ligands derived from optically active alpha-amino acids or alpha-hydroxycarboxylic acids were isolated as enantiomerically and diastereomerically pure compounds that undergo a (Lambda)/(Delta)-epimerization in solution.
authors.affiliation: Institut für Anorganische Chemie, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany. r.tacke@mail.uni-wuerzburg.de
authors.forename: Reinhold
authors.initials: R
authors.lastname: Tacke
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Bertermann
authors.forename: Christian
authors.initials: C
authors.lastname: Burschka
authors.forename: Simona
authors.initials: S
authors.lastname: Dragota
authors.forename: Martin
authors.initials: M
authors.lastname: Penka
authors.forename: Ingo
authors.initials: I
authors.lastname: Richter
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D002264:Carboxylic Acids / Q000737:chemistry*; D007477:Ions; D007700:Kinetics; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D015394:Molecular Structure; D017640:Silicates / Q000138:chemical synthesis / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000596:Amino Acids; D002264:Carboxylic Acids; D007477:Ions; D008024:Ligands; D017640:Silicates