title: [M(rac-N-benzyl Asp)(H2O)] (M = Co, Ni): noncentrosymmetric coordination polymeric chains with racemic chiral ligands.
abstract: The hydrothermal reaction of fumaric acid, benzylamine, and metal salts yielded M[(rac-N-benzyl-Asp)(H(2)O)] (M = Co, Ni), 1 and 2, and Ni[(rac-N-benzyl-Asp)(H(2)O)(3)]·H(2)O 3. Under mild hydrothermal conditions, Michael addition of benzylamine to fumaric acid led to the formation of a racemic mixture of N-benzyl aspartic acid enantiomers. The noncentrosymmetric structures of 1 and 2 consist of one-dimensional polymeric chains in which metal cations are bridged by d- and l-N-benzyl aspartate anions alternating along the chain. The centrosymmetric structure of 3 is composed of discrete Ni[(rac-N-benzyl-Asp)(H(2)O)(3)] units that are connected by hydrogen bonds into layers. The single layers are homochiral but are hydrogen bonded to similar homochiral layers that contain the N-benzyl aspartate with the opposite handedness. Compounds 1 and 2 showed second harmonic generation (SHG), and their magnetic and thermodynamic properties are described.
authors.affiliation: Department of Chemistry, Konkuk University, Seoul 143-701, Republic of Korea. junghwan@konkuk.ac.kr
authors.forename: Junghwan
authors.initials: J
authors.lastname: Do
authors.forename: Yumi
authors.initials: Y
authors.lastname: Lee
authors.forename: Jaeun
authors.initials: J
authors.lastname: Kang
authors.forename: Yong Sun
authors.initials: YS
authors.lastname: Park
authors.forename: Bernd
authors.initials: B
authors.lastname: Lorenz
authors.forename: Allan J
authors.initials: AJ
authors.lastname: Jacobson