Exploiting Reaction-Diffusion Conditions to Trigger Pathway Complexity in the Growth of a MOF

Abstract

Coordinationpolymers(CPs),includingmetal-organicframeworks(MOFs),are crystallinematerialswithpromisingapplicationsin electronics,magnetism,catalysis,andgas storage/separation.However,the mechanismsandpath-waysunderlyingtheirformationremainlargelyundisclosed.Herein,we demonstratethatdiffusion-controlledmixingofreagentsat the veryearlystagesof the crystallizationprocess(i.e., within 40 ms),achievedby usingcontinuous-flowmicrofluidicdevices,can be usedto enablenovelcrystallizationpathwaysofaprototypicalspin-crossover MOFtowards itsthermodynamicproduct.In particular,twodistinctandunprecedentednucleation-growth pathwayswere experimen-tallyobservedwhencrystallizationwas triggeredundermicro-fluidicmixing.Full-atommoleculardynamicssimulationsalsoconfirmthe occurrenceof thesetwo distinctpathwaysduringcrystalgrowth.In sharpcontrast,acrystallizationby particleattachmentwas observedunderbulk(turbulent)mixing.Theseunprecedentedresultsprovideasoundbasisfor understandingthe growth of CPsand openup newavenuesfor the engineer-ing of porousmaterialsby usingout-of-equilibriumconditions