Matthew Chrzanowski

Introduction of π-Complexation into Porous Aromatic Framework for Highly Selective Adsorption of Ethylene over Ethane

In this work, we demonstrate for the first time the introduction of π-complexation into a porous aromatic framework (PAF), affording significant increase in ethylene uptake capacity, as illustrated in the context of Ag(I) ion functionalized PAF-1, PAF-1-SO3Ag. IAST calculations using single-component-isotherm data and an equimolar ethylene/ethane ratio at 296 K reveal that PAF-1-SO3Ag shows exceptionally high ethylene/ethane adsorption selectivity (Sads: 27 to 125), far surpassing benchmark zeolite and any other MOF reported in literature. The formation of π-complexation between ethylene molecules and Ag(I) ions in PAF-1-SO3Ag has been evidenced by the high isosteric heats of adsorption of C2H4 and also proved by in situ IR spectroscopy studies. Transient breakthrough experiments, supported by simulations, indicate the feasibility of PAF-1-SO3Ag for producing 99.95%+ pure C2H4 in a Pressure Swing Adsorption operation. Our work herein thus suggests a new perspective to functionalizing PAFs and other types of advanced porous materials for highly selective adsorption of ethylene over ethane.

Metal–Organic Framework Based upon the Synergy of a Brønsted Acid Framework and Lewis Acid Centers as a Highly Efficient Heterogeneous Catalyst for Fixed-Bed Reactions

We report a strategy of combining a Brønsted acid metal-organic framework (MOF) with Lewis acid centers to afford a Lewis acid@Brønsted acid MOF with high catalytic activity, as exemplified in the context of MIL-101-Cr-SO3H·Al(III). Because of the synergy between the Brønsted acid framework and the Al(III) Lewis acid centers, MIL-101-Cr-SO3H·Al(III) demonstrates excellent catalytic performance in a series of fixed-bed reactions, outperforming two benchmark zeolite catalysts (H-Beta and HMOR). Our work therefore not only provides a new approach to achieve high catalytic activity in MOFs but also paves a way to develop MOFs as a new type of highly efficient heterogeneous catalysts for fixed-bed reactions.

Vertex-directed self-assembly of a high symmetry supermolecular building block using a custom-designed porphyrin

Metal–organic materials that are constructed from polyhedral supermolecular building blocks, SBBs, can offer exquisite control over structure and afford useful features such as multiple cage types and relatively narrow pores. This contribution describes how a custom-designed porphyrin, tdcpp, self-assembles with M(II) (M = Zn, Cd) cations to generate the first examples of SBBs that are uniform polyhedra based upon a porphyrin molecular building block, MBB. The faces of tdcpp moieties link triangular M2(CO2)3 or M(CO2)3 moieties to form small cubicuboctahedral SBBs that are in turn fused to adjacent SBBs at the opposite face of each tdcpp moiety. The resulting high symmetry augmented pcu topology networks, MMPF-4 (M = Zn) and MMPF-5 (M = Cd), exhibit two distinct polyhedral cages and are permanently microporous with selective CO2 uptake.

Formation of a Metalloporphyrin‐Based Nanoreactor by Postsynthetic Metal–Ion Exchange of a Polyhedral‐Cage Containing a Metal–Metalloporphyrin Framework

A change for the better: Exchange of Cd(II) in the catalytically inactive framework MMPF-5 (see scheme) with Co(II) afforded a metalloporphyrin-based nanoreactor, MMPF-5(Co). This framework, consisting of small cubicuboctahedral cages, demonstrated interesting performances in the catalytic epoxidation of trans-stilbene with tBuOOH.