Self-assembly of linear-shaped bi-dihydrazine derivative through intermolecular quadruple hydrogen bonding

A linear-shaped bi-1,3,4-oxadiazole derivative, oxalyl acid N',N'-di(4-(2 -ethylhexyloxy)benzoyl)-hydrazide (FH-Z8) was designed and synthesized. Quadruple hydrogen bonds between bi-dihydrazide units and pi-pi interactions cooperatively participated in forming supramolecules in chloroform at higher concentrations of FH-Z8. The association constants (K) in chloroform were 2.2 x 10(3) and 1.8 x 10(3) M-1 based on NH1 and NH2 in FH-Z8, respectively. FH-Z8 could gel dichloroethane efficiently with the critical gelation concentration (CGC) of 0.14 wt%, while spontaneously crystallized from the gel during storage. (C) 2008 Elsevier Ltd. All rights reserved.