Synthesis and Characterization of Self-Assembled Chiral Fe^II ₂ L₃ Cages.

ABSTRACT: We present here the synthesis of chiral BINOL-derived (BINOL=1,1'-bi-2-naphthol) bisamine and bispyridine-aldehyde building blocks that can be used for the self-assembly of novel chiral Fe^II ₂ L₃ cages when mixed with an iron(II) precursor. The properties of a series of chiral cages were studied by NMR and circular dichroism (CD) spectroscopy, cold-spray ionization MS, and molecular modeling. Upon formation of the M₂ L₃ cages, the iron corners can adopt various isomeric forms: mer, fac-?, or fac-?. We found that the coordination geometry around the metal centers in R-Cages?1 and 2 were influenced by the chiral BINOL backbone only to a limited extent, as a mixture of cages was formed with fac and mer configurations at the iron corners. However, single cage species (fac-RR-Cage and fac-RS-Cage) that are enantiopure and highly symmetric were obtained by generating these chiral M₂ L₃ cages by using the bispyridine-aldehyde building blocks in combination with chiral amine moieties to form pyridylimine ligands for coordination to iron. Next to consistent NMR spectra, the CD spectra confirm the configurations fac-(?,?) and fac-(?,?) corresponding to RR- and RS-Cage, respectively.

SUBMITTER: Sun B 

PROVIDER: S-EPMC6175241 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature