RESOLUTION OF OPTICALLY-ACTIVE TRIS(DIKETONATO) AND BIS(DIKETONATO) METAL(III) COMPLEXES AND THEIR MONOLAYER PROPERTIES AT AN AIR-WATER-INTERFACE

The monolayer properties of tris- and his (diketonato) metal(III) comp lexes were investigated at the air-water interface. The following eigh t complexes were synthesized: [Cr(acacNO(2))(3)] (acacNO(2) = 3-nitrop entane-2,4-dionato), [Co(adacNO(2))(3)], [Ru(PHE)(3)] (PHE = 1,3-diphe nylpropane-1,3-dionato), [Ru(HPD)(3)] (HPD = heptane-3,5-dionato), [Ru (NND)(3)] (NND = nonane-4,6-dionato), [Ru(DMH)(3)] (DMH = dimethylhept ane-3,5-dionato),fac-[Ru(acacF(3))(3)] (acacF(3) = 1-1,3-bis(trifluoro methyl)propane-l,3-dionato) and [Ru(acac)(2)(PHE)]. When these complex es were eluted with a methanol-chloroform mixture on a column packed w ith Delta-[Ru(phen)(3)](2+)/laponite , resolution was achieved for [Cr (acacNO(2))(3)], [Co(acacNO(2))(3)], [Ru(HPD)(3)], [Ru(NND)(3)] and [R u(acac)(2)(PHE)]. To study the monolayer behavior, a chloroform soluti on of a ruthenium(III) complex was spread onto a water surface and a s urface pressure-molecular area (pi-A) curve was measured. The pi-A cur ves for [Ru(DMH)(3)],fac-[Ru(acacF(3))(3)] and [Ru(NND)(3)] were rever sible. The pi-A curves for other compounds displaced irreversibly towa rds smaller molecular areas on the second compression, indicating that the compounds formed microcrystallites under high surface pressure. I n the case of [Ru(NND)(3)], the stereochemical effects on monolayer fo rmation were studied by comparing the pi-A curves between a racemic mi xture and an enantiomer. As a result, the racemic mixture of the compl ex was found to form a more compact monolayer than the pure enantiomer .