화학공학소재연구정보센터
Inorganic Chemistry, Vol.42, No.15, 4545-4552, 2003
Trinuclear heterobimetallic complexes with binucleating dithioxamides: Stereoselective synthesis and solution behavior involving Pd-N bond rupture
Bischelate platinum(11) complexes of the type [Pt(H-R-2-N2C2S2)(2)] (H-R-2-N2C2S2- = dialkyl-dithioxamidate) are ditopic receptors which, after coordination of the first Pd(eta(3)-allyl)(+) moiety, induce the orientation of the second palladium-allyl fragment. Thus, a series of trimetallic complexes of formula bis-[(eta(3)-allyl)-palladium(II)](mu-bis-dialkyl-dithioxamidate-platinum(II) kappa-S,S-kappa-S',S'-Pt-kappa-N,N-Pd-kappa-N',N'-Pd') has been prepared in which the allyl fragments are oriented toward the same side of the molecular plane. We have also prepared the trimetallic complex using a dithioxamide obtained from the racemic phenylethylamine. Only two isomers were produced in equimolar ratio: the racemate that has four homochiral alkyl substituents and the mesoform containing the meso-dithioxamide that has homochiral substituents on the same side of molecular plane. Under the effect of the temperature, the trimetallic Pd-Pt-Pd complexes undergo rapid allyl isomerization; the mechanism of the isomerization, which is similar to that found by us in an analogue Pt-Pd bimetallic complex, is discussed. The crystal and molecular structure of bis-[(eta(3)-allyl)-palladium(II)](mu-bis-{S}-phenylethyl-dithioxamidate-platinum(11) kappa-S,S-kappa-S',S'-Pt-kappa-N,N-Pd-kappa-N',N'-Pd') has been reported.