Differentiation of Epoxide Enantiomers in the Confined Spaces of an Homochiral Cu(II) MOF by Kinetic Resolution

TAMOF-1, a homochiral metal-organic framework (MOF) constructed from an amino acid derivative and Cu(II), was investigated as a heterogeneous catalyst in kinetic resolutions involving the ring opening of styrene oxide with a set of anilines. The branched products generated from the ring opening of styrene oxide with anilines and the unreacted epoxide were obtained with moderately high enantiomeric excesses. The linear product arising from the attack on the non-benzylic position of styrene oxide underwent a second kinetic resolution by reacting with the epoxide, resulting in an amplification of its final enantiomeric excess and a concomitant formation of an array of isomeric aminodiols. Computational studies confirmed the experimental results, providing a deep understanding of the whole process involving the two successive kinetic resolutions. Furthermore, TAMOF-1 activity was conserved after several catalytic cycles. The ring opening of a mesoepoxide with aniline catalyzed by TAMOF-1 was also studied and moderate enantioselectivities were obtained

Polynuclear Fe(II) complexes: Di/trinuclear molecules and coordination networks

We review here the recent progress made in the synthesis of spin crossover (SCO) Fe(II) coordination complexes with two or three metal atoms, as well as coordination polymers, with the main focus on that in the last five years. We discuss these as well as their magnetic properties to derive magnetostructural correlations. This manuscript is organized through the ligand types that serve to produce the various coordination systems presented. The ligand structure and essential SCO parameters of the complexes are gathered in comprehensive figures and tables. This review illustrates the richness and key parameters of coordination chemistry to develop multiple architectures with the desired properties involving this fascinating phenomeno

Molecular memory near room temperature in an iron polyanionic complex

Single molecules are the smallest processable units for information storage and sensing. However, molecular phenomena are typically limited to very low temperatures. Thermal energy is able to depopulate (erase) the excited state back to the ground state. Spin-crossover (SCO) molecules are an exception to this rule, showing memory effect above room temperature, but only when the electronic switchability is associated with a bulk phase transition. This synergy has its origin in the cooperativity among SCO molecules in the crystal, disappearing in diluted samples. We have found a surprising exception to this model: a polyanionic iron complex capable of showing memory effect even upon dilution. Our results demonstrate that molecular species can exhibit thermal hysteresis if intramolecular interactions are able to slow down the relaxation processes at the single-molecule level. Our findings open unprecedented opportunities for single-molecule memories at (and above) room temperature