The antimutagenic effects of 27 kinds of plant flavonoids on the mutagenicity of aflatoxin B1(AFB1) and N-methyl-N'-nitro-N-nitrosoguanidine(MNNG) in Salmonella typhimurium TA100 were investigated. In the mixed applications of AFB1 (1 microgram/plate) with the flavonoids (300 micrograms/plate) in the presence of a mammalian metabolic activation system (S9 mix), chrysin, apigenin, luteolin and its glucoside, kaempferol, fisetin, morin, naringenin, hesperetin, persicogenin, (+)-catechin and (-)-epicatechin showed the antimutagenic effect against AFB1 with more than 70% inhibition rate. A little or no antimutagenicities except flavone against MNNG (0.5 microgram/plate) were observed. For the antimutagenicity of the flavonoids on AFB1, the flavonoid structure that contains the free 5-, 7-hydroxyl group seemed to be essential. However, saturation of the 2,3-double bond or elimination of the 4-keto group did not affect the activity.

During the last four decades, the chemistry of macrocyclic and non-cyclic polyethers has attracted an increasing attention because of their selective complexation, cation transport and enzyme chemistry. [1][2][3][4][5] In the field of coordination chemistry, generally, non-cyclic, crown-type polyether affords the low complexation ability because of its conformational freedom while macrocyclic polyethers such as 18-crown-6 show the excellent complexing ability. However, the open chain oligoethylene glycols, so-called podands, with rigid aromatic donor end-groups at the both ends of the oligo(ethylene glycol) backbone have been reported on the considerable enhancement of complexing stabilities.4c Especially, the 1,13-bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane (L) has been spotlighted as a key podand because of its attractive characteristics to form a pseudo cyclic complex with metal ion by the intra-stacking interaction between two quinoline end-groups. 6 According to our and other's works on complexation of L against the transition metal ions, 7 L was also found to form the stable complexes with Ag + or Hg 2+ ions in solid state owing to two quinoline end-groups of L.Recently, we have reported the unique pseudo-cyclic Cd(II) complexes [Cd(L)(H2O)(CH3OH)](ClO4)2 (1a) and [Cd(L) (H 2 O)(NO 3 )](NO 3 ) (1b), in which the dipodal receptor (L) with quinoline end-groups wrapped around the cadmium atom in a helical mode, obtained by self-assembly of the dipodal ligand (L) and CdX2 (X = ClO4 and NO3) ( Figure S1 in Supporting Information).8 As a part of ongoing efforts for the complexation of L against transition metal ions, we prepared another Cd(II) complex with chloride anion. Herein, we report crystal structure and thermal behavior of dinuclear Cd(II) complex (2). Fig. 1. In the asymmetric unit of 2, there are two crystallographically independent Cd atoms which adopt the distorted pentagonal bipyramidal geometries with seven-coordinate number, being bound to three O and one N donors of L and three Cl atoms. The O3N donors of L and one bridging Cl atom (Cl3

2), have been synthesized by typical cross-coupling reactions. Both compounds have been characterized by single-crystal X-ray diffraction. Bipyridine 1 exhibits a fully extended structure in which the terminal pyridine rings are oriented away from each other, while bipyridine 2 displays a bent structure in which terminal pyridine rings are oriented in the same direction. Several intermolecular interactions lead to the formation of two-and three-dimensional supramolecular networks in the crystal structures of 1 and 2, respectively. Compound 1 bears fluorine substituents and emits a strong fluorescence with max = 325 nm, while methoxy-substituted compound 2 displays red-shifted emissions with max = 366 nm. The emissions observed in both compounds originate from phenyl-and 2,3 0 -bipyridine-based -* transitions, according to theoretical calculations. Both compounds have high triplet energies (T 1 ) ranging from 2.64 to 2.65 eV, which makes them potential host materials in organic light-emitting diodes (OLEDs).