Chirality- and pH-Controlled Supramolecular Isomerism in Cobalt Phosphonates and Its Impact on the Magnetic Behavior.
Two pairs of enantiomeric compounds with formulas (S)- or (R)-Co3 (ppap)2 (4,4'-bpy)2 (H2 O)2 ⋅4 H2 O [(S)-1 or (R)-1], (S)- or (R)-Co3 (ppap)2 (4,4'-bpy)2 (H2 O)2 ⋅3 H2 O [(S)- or (R)-2), and related racemic compound Co3 (ppap)2 (4,4'-bpy)2 (H2 O)2 ⋅4 H2 O (rac-3; 4,4'-bpy=4,4'-bipyridine, H3 ppap=3-phenyl-2-[(phosphonomethyl)amino]propanoic acid) are reported. Compounds 1 and rac-3 show identical three-dimensional framework structures, whereas compounds 2 have two-dimensional layer structures. Compounds 1 and 2 are catenation isomers, formation of which is controlled solely by the pH of the reaction mixtures, whereas the formation of isomeric compounds 1 and rac-3 is controlled purely by the chirality of the phosphonate ligand. The magnetic properties of fully dehydrated (S)-1, (S)-2, and rac-3 are highly dependent on both structure and chirality.
State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (P. R. China).|School of Chemistry and Pharmaceutical Engineering, Sichuan University of Science & Engineering, Zigong 643000 (P. R. China).
Jian-Shen
JS
Feng
State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (P. R. China).
Song-Song
SS
Bao
State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (P. R. China).
Min
M
Ren
State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (P. R. China).
Zhong-Sheng
ZS
Cai
State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (P. R. China). lmzheng@nju.edu.cn.
Li-Min
LM
Zheng
N,O ligands; chirality; cobalt; isomers; magnetic properties