Ordering of metal chelates on the basis of bilayer assembly

Abstract

We report herein strong intermetallic interactions of Cu(I1) chelates formed at the surface of bilayer aggregates.Synthetic bilayer membranes are two-dimensional arrays of molecules and are useful vehicles for ordering of part or whole molecules because of their structural flexibility. The molecular ordering produces various interesting properties. For instance, efficient energy migration among chromophores was implied in ammonium bilayers that contained anthracene' and carbazole2 units, and large enhancements due to extensive dipolar coupling were observed in circular dichroism of chiral bilayer membranes." These unique characteristics should be similarly applicable to preparation of ordered arrays of metal chelates.Simon and others carried out extensive investigations on micellar and liquid-crystalline metal c~m p l e x e s~~~ and found, among other results, a remarkable enhancement of the dioxygen stability constant for micellar cobaltous complexes.8 We examined previously the interaction of metal ions with ligands at the bilayer surface, which caused subsequent changes of membrane physical state^.^,'^ In these cases, however, the direct interaction of metal

Anion binding to neutral and positively-charged lipid membranes

“…Electrostatic considerations predict that the binding of aqueous anions should be enhanced by the presence of a positively charged membrane surface. Such a condition may be created by mixing neutral POPC with synthetic cationic amphiphiles (Winiski et al, 1986;Seelig and Scherer, unpublished results), Provided their hydrocarbon chains are sufficiently long, such amphiphiles spontaneously aggregate into bilayers (Kunitake, 1979;Fendler, 1980;Kunitake et al, 1986). Figures 5 and 6 show 2H NMR spectra and the corresponding 31P NMR spectra for lipid membranes composed of 20 mol % dihexadecyldimethylammonium bromide (DHDMAB) plus 80 mol % either a-CD2-or @-CD,-POPC, respectively, and hydrated in buffer with or without 1.0 M NaSCN.…”

Efficient Catalysis of a Diels−Alder Reaction by Metallo-Vesicles in Aqueous Solution

“…Several groups have reported bilayer structures with copper(II) as counterions , including vesicular morphology; also combinations of copper ions with chelating compounds, forming bilayer or vesicle − structures, are known.…”

Thermal Modulation of Photoisomerization in Double-Azobenzene-Chain Liposomes

“…Utilization of this principle is fostered by the assembly of AB-containing lipids into aggregates that function as molecular devices with photoresponsive properties. Kunitake's group, in particular, has pioneered the correlation between the molecular structure of AB lipids and the morphology and spectroscopic properties of their aggregates, especially bilayer assemblies. 1bc,− …”