meta-Substituted benzamide oligomers that complex mono-, di- and tricarboxylates: folding-induced selectivity and chirality.
meta-Substituted arylamide trimer, pentamer and heptamer have been prepared from simple benzene-1,3-diamine, benzene-1,3-dicarboxylic acid, and 3-aminobenzoic acid units. 2D NOESY (1)H NMR experiments reveal that these flexible oligomers form folded conformations to complex di- and tricarboxylate anions of varying sizes and shapes in DMSO of high polarity, which is driven by multiple intermolecular N-H···O=C and C-H···O=C hydrogen-bonds between the amide and aromatic hydrogens of the oligomers and the carboxylate oxygens of the anions. Generally, tricarboxylate anions display an increased binding affinity compared with the dicarboxylate anions and the complexes formed by 1,3-benzenedicarboxylate anion are more stable than those formed by 1,2- or 1,4-benzenedicarboxylate anions. Circular dichroism experiments show that chiral glutamic acid dianion can induce the oligomers to produce chiral bias, leading to the formation of chiral supramolecular complexes.
State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China.
Zhu-Ming
ZM
Shi
Shi-Gui
SG
Chen
Xin
X
Zhao
Xi-Kui
XK
Jiang
Zhan-Ting
ZT
Li
D001549:Benzamides / Q000737:chemistry*; D002264:Carboxylic Acids / Q000737:chemistry*; D015394:Molecular Structure; D013237:Stereoisomerism
D001549:Benzamides; D002264:Carboxylic Acids; C037689:benzamide