Daniel Prochowicz

Cinchona Alkaloid-Metal Complexes: Noncovalent Porous Materials with Unique Gas Separation Properties**

The most common andeffective approach to design and prepare metal–organicframeworks (MOFs) or porous coordination polymers(PCPs) of desired topology and functionality is based oncoordination-driven self-assembly, and both the correctchoice of metal centers and the engineering of the ligandsfeatures, such as size, flexibility, and directionality of bindingcenters, play a decisive role.

Permanent Porosity Derived From the Self-Assembly of Highly Luminescent Molecular Zinc Carbonate Nanoclusters†

Over the past two decades, crystalline microporous materials have attracted major interest, owing to their applications in gas sorption, separation, catalysis, and sensing. Microporous crystalline materials can be constructed from coordinatively or covalently linked building blocks where rigid or semi-rigid molecular scaffolds separate void spaces of different size and geometry. Prominent examples of porous materials showing polymeric structures include zeolites, hybrid metal–organic frameworks (MOFs) or porous coordination polymers (PCPs), covalent organic frameworks (COFs), and Hbonded supramolecular organic frameworks (SOFs). The formation of bonding interactions between building units is an important factor that defines and controls the stability and robustness of these porous polymeric materials. However, discrete molecules may also pack in the solid state to form 3D assemblies that exhibit high permanent porosity. The resulting noncovalent porous materials (NPMs) are distinct from the above polymeric systems, as they are held together by weak noncovalent crystal-packing forces. Modifications of structure by cocrystallization of different building blocks can tune the microcavities in the solid state, and the material can thus conform to the shape or functionality of guest molecules. Moreover, these materials can be highly solubile, an important advantage in their processing to form porous thin films. NPMs can exhibit extrinsic and/or intrinsic porosity. Intrinsic porosity is associated with the structure of the single-molecule-containing voids, clefts, or cavities, as has been demonstrated for calixarenes, cucurbiturils, cyclodextrins, organic cage compounds, or discrete small organic molecules. In contrast, materials with extrinsic porosity are those where individual molecules pack in the solid-state to form structures with empty spaces between the individual molecules. As discrete molecules tend to form close-packed solids with minimal void volume, extrinsic porosity in NPMs remains a rare phenomenon. The rational design and preparation of NPMs showing extrinsic porosity based on molecular metal complexes is highly challenging and few examples have been reported. We have demonstrated previously that alkylzinc hydroxides RZnOH can be efficiently transformed into multinuclear alkyzinc carbonate nanoclusters or nanomaterials, such as discrete nanoparticulate zinc carbonate aerogels and ZnO nanoparticles. As shown in Scheme 1a, the reactivity of the RZnOH species can be rationalized in terms of the presence of both a proton-reactive Zn C bond and CO2-reactive Zn OH groups. We argued that introduction of an additional auxiliary ligand L to the RZnOH system, followed by CO2 fixation, could lead to the formation of novel molecular building blocks for new extrinsic NPMs. Herein, we report such a strategy in which the construction of a nanosized cluster [Zn10(m6-CO3)4(L)12] (WUT-1; WUT=Warsaw University of Technology) is achieved by fixation of CO2 by the tetranuclear hydroxo precursor [Zn4(m3-OH)2(L)4(tBu)2] (1;

Oxozinc carboxylate complexes: a new synthetic approach and the carboxylate ligand effect on the noncovalent-interactions-driven self-assembly.

An atom-efficient and mild synthesis of a series of oxozinc carboxylates [Zn(4)(μ(4)-O)(O(2)CR)(6)] [where R = Ph (2a), p-PhC(6)H(4) (2b), p-MeC(6)H(4) (2c), and p-MeSC(6)H(4) (2d)] from well-defined alkylzinc precursors and H(2)O is described. The molecular and crystal structures of the resulting complexes have been determined by single-crystal X-ray diffraction. A closer examination of their crystal structure provides a direct picture of the effect of the nature of substituents on the molecular self-assembly of the octahedral oxozinc through noncovalent interactions. It was revealed that these discrete oxozinc clusters can form diverse types of noncovalent assemblies ranging from structures representing zeolitic topologies in the case of 2a to soft porous materials with gated voids or open channels for the remaining molecular clusters.

Cation Dynamics in Mixed-Cation (MA)x(FA)1–xPbI3 Hybrid Perovskites from Solid-State NMR

Mixed-cation organic lead halide perovskites attract unfaltering attention owing to their excellent photovoltaic properties. Currently, the best performing perovskite materials contain multiple cations and provide power conversion efficiencies up to around 22%. Here, we report the first quantitative, cation-specific data on cation reorientation dynamics in hybrid mixed-cation formamidinium (FA)/methylammonium (MA) lead halide perovskites. We use 14N, 2H, 13C, and 1H solid-state MAS NMR to elucidate cation reorientation dynamics, microscopic phase composition, and the MA/FA ratio, in (MA)x(FA)1-xPbI3 between 100 and 330 K. The reorientation rates correlate in a striking manner with the carrier lifetimes previously reported for these materials and provide evidence of the polaronic nature of charge carriers in PV perovskites.

Mechanosynthesis of the hybrid perovskite CH3NH3PbI3: characterization and the corresponding solar cell efficiency

We present a facile mechanochemical route for the preparation of hybrid CH3NH3PbI3 (MAPbI3) perovskite particles with the size of several hundred nanometers for high-efficiency thin-film photovoltaic devices. Powder X-ray diffraction measurements demonstrate that mechanosynthesis is a suitable strategy to produce a highly crystalline CH3NH3PbI3 material showing no detectable amounts of the starting CH3NH3I and PbI2 reagents. Thermal stability measurements based on the thermogravimetric analysis data of mechanosynthesized perovskite particles indicated that the as-ground MAPbI3 is stable up to 300 °C with no detectable material loss at lower temperatures. The optical properties of newly synthesized perovskite particles were characterized by applying steady state absorption and fluorescence spectroscopy, which confirmed a direct band-gap of 1.48 eV. Time resolved single photon counting measurements revealed that 70% of charges undergo recombination with a 61 ns lifetime. The solar cell devices made from mechanosynthesized perovskite particles achieved a power conversion efficiency of 9.1% when applying a one step deposition method.

Phase Segregation in Cs-, Rb- and K-doped Mixed-Cation (MA)x(FA)1-xPbI3 Hybrid Perovskites from Solid-State NMR

Hybrid (organic–inorganic) multication lead halide perovskites hold promise for a new generation of easily processable solar cells. Best performing compositions to date are multiple-cation solid alloys of formamidinium (FA), methylammonium (MA), cesium, and rubidium lead halides which provide power conversion efficiencies up to around 22%. Here, we elucidate the atomic-level nature of Cs and Rb incorporation into the perovskite lattice of FA-based materials. We use 133Cs, 87Rb, 39K, 13C, and 14N solid-state MAS NMR to probe microscopic composition of Cs-, Rb-, K-, MA-, and FA-containing phases in double-, triple-, and quadruple-cation lead halides in bulk and in a thin film. Contrary to previous reports, we have found no proof of Rb or K incorporation into the 3D perovskite lattice in these systems. We also show that the structure of bulk mechanochemical perovskites bears close resemblance to that of thin films, making them a good benchmark for structural studies. These findings provide fundamental understanding of previously reported excellent photovoltaic parameters in these systems and their superior stability.

Trinuclear Cage‐Like ZnII Macrocyclic Complexes: Enantiomeric Recognition and Gas Adsorption Properties

Three zinc(II) ions in combination with two units of enantiopure [3+3] triphenolic Schiff-base macrocycles 1, 2, 3, or 4 form cage-like chiral complexes. The formation of these complexes is accompanied by the enantioselective self-recognition of chiral macrocyclic units. The X-ray crystal structures of these trinuclear complexes show hollow metal-organic molecules. In some crystal forms, these barrel-shaped complexes are arranged in a window-to-window fashion, which results in the formation of 1D channels and a combination of both intrinsic and extrinsic porosity. The microporous nature of the [Zn3 12 ] complex is reflected in its N2 , Ar, H2 , and CO2 adsorption properties. The N2 and Ar adsorption isotherms show pressure-gating behavior, which is without precedent for any noncovalent porous material. A comparison of the structures of the [Zn3 12 ] and [Zn3 32 ] complexes with that of the free macrocycle H3 1 reveals a striking structural similarity. In H3 1, two macrocyclic units are stitched together by hydrogen bonds to form a cage very similar to that formed by two macrocyclic units stitched together by Zn(II) ions. This structural similarity is manifested also by the gas adsorption properties of the free H3 1 macrocycle. Recrystallization of [Zn3 12 ] in the presence of racemic 2-butanol resulted in the enantioselective binding of (S)-2-butanol inside the cage through the coordination to one of the Zn(II) ions.

Construction of a Porous Homochiral Coordination Polymer with Two Types of CunIn Alternating Units Linked by Quinine: A Solvothermal and a Mechanochemical Approach

The polymer network: The reaction of quinine (QN) with CuI under solvothermal, as well as liquid-assisted grinding, conditions afforded a unique 1D homochiral coordination polymer {[Cu(4)(μ(3)-I)(4)(QN)(2)][Cu(3)(μ(3)-I)(2)(μ(2)-I)(QN)(2)](2)}(n), containing both triangular Cu(3)I(3) and cubane Cu(4)I(4) clusters as connecting nodes (see scheme). Van der Waals interactions between the adjacent 1D polymer chains lead to an extended quasi-honeycomb homochiral pillared 3D network with solvent-free 1D channels.

Molecularly Imprinted Polymer (MIP) Film with Improved Surface Area Developed by Using Metal–Organic Framework (MOF) for Sensitive Lipocalin (NGAL) Determination

Electropolymerizable functional and cross-linking monomers were used to prepare conducting molecularly imprinted polymer film with improved surface area with the help of a sacrificial metal-organic framework (MOF). Subsequent dissolution of the MOF layer resulted in a surface developed MIP film. This surface enlargement increased the analyte accessibility to imprinted molecular cavities. Application of the porous MIP film as a recognition unit of an extended-gate field effect transistor (EG-FET) chemosensor effectively enhanced analytical current signals of determination of recombinant human neutrophil gelatinase-associated lipocalin (NGAL).

Mechanosynthesis of pure phase mixed-cation MAxFA1−xPbI3 hybrid perovskites: photovoltaic performance and electrochemical properties

We report a facile mechanochemical route for the stabilization of a structurally stable α-FAPbI3 perovskite by fine and controllable stoichiometry modification in mixed-cation (MA)x(FA)1−xPbI3 perovskites. Moreover, the mechanoperovskite with a composition of (MA)0.25(FA)0.75PbI3 was used for solar cell fabrication showing a power conversion efficiency (PCE) of 14.98% with a high short circuit current (JSC) density at 23.7 mA cm−2.