title: Synthesis of novel chiral and acentric coordination polymers by the reaction of zinc or cadmium salts with racemic 3-pyridyl-3-aminopropionic acid.
abstract: Under hydrothermal (solvothermal) reaction conditions chiral compounds 1, 2, and 3 and one acentric compound 4 were obtained by the reaction of Zn(2+) or Cd(2+) with racemic 3-(3-pyridyl)-3-aminopropionic acid (rac-HPAPA). Compounds 1 and 2 crystallized in chiral space group P2(1)2(1)2(1). At 105 degrees C, racemic 3-pyridyl-3-aminopropionic acid (rac-HPAPA) reacted with Zn(ClO4)(2).6 H2O and dehydrogenated in situ to form the first chiral coordination polymer [Zn[(E)-3-C(5)H4N-C(NH2)=CH-COO]]ClO4 (1) with a beta-dehydroamino acid. Beyond 120 degrees C, the reaction of rac-HPAPA with Zn(ClO4)(2).6 H2O deaminates in situ to form chiral coordination polymer [Zn[(E)-3-C5H4N-CH=CH-COO](OH)] (2). At relatively low temperatures (70 degrees C), the solvothermal reaction of Zn(NO3)(2).6 H2O with rac-HPAPA in methanol does not lead to any change in the ligand and results in the formation of a chiral (P2(1)2(1)2(1)) coordination polymer [Zn(papa)(NO3)] (3). The same reaction of Cd(ClO4)(2).6 H2O with HPAPA also does not lead to any change in ligand and results in the formation of noncentric (Cc) coordination polymer [Cd(papa)(Hpapa)]ClO4.H2O (4). The network topology of both 1 and 3 is 10,3a, while 2 has a diamondoid-like (KDP-like, KDP=potassium dideuterophosphate) network. Particularly interesting from a topological perspective is that 4 has an unprecedented three-dimensional network. Compounds 1, 2, 3, and 4 are all second harmonic generation (SHG) active with 1 exhibiting the strongest response, while only 4 also displays good ferroelectric properties.
authors.affiliation: Coordination Chemistry Institute, The State Key Laboratory of Coordination Chemistry, Nanjing University, 210093 Nanjing, P. R. China.
authors.forename: Zhi-Rong
authors.initials: ZR
authors.lastname: Qu
authors.forename: Hong
authors.initials: H
authors.lastname: Zhao
authors.forename: Yi-Ping
authors.initials: YP
authors.lastname: Wang
authors.forename: Xi-Sen
authors.initials: XS
authors.lastname: Wang
authors.forename: Qiong
authors.initials: Q
authors.lastname: Ye
authors.forename: Yong-Hua
authors.initials: YH
authors.lastname: Li
authors.forename: Ren-Gen
authors.initials: RG
authors.lastname: Xiong
authors.forename: Brendan F
authors.initials: BF
authors.lastname: Abrahams
authors.forename: Zhi-Guo
authors.initials: ZG
authors.lastname: Liu
authors.forename: Zi-Ling
authors.initials: ZL
authors.lastname: Xue
authors.forename: Xiao-Zeng
authors.initials: XZ
authors.lastname: You