Zeolites are readily available crystalline materials with intrinsic porosity, and their outstanding physical and chemical properties have been demonstrated in many areas, including catalysis, adsorption, ion exchange, and gas separation. Their insulating character has so far prevented the development of zeolite-based devices; however, given their non-toxic nature and abundance, it would be worthwhile to investigate their charge transport properties, as the inherent micro-, meso- and macropores offer specific structuring and modification options for various engineering and biomedical applications. Here, two faujasite Na-FAU type zeolites with different particle sizes, nanosized (n-FAU) and microsized (& micro;-FAU) zeolite samples, were prepared to comprehensively investigate their electrical properties. To elucidate the complex interplay between morphology, degree of hydration, and overall electrical performance of the studied zeolites, structural (powder X-ray diffraction under ambient and non-ambient conditions), microstructural (scanning electron microscopy, light-scattering particle size analysis, and porosimetry), thermal (thermogravimetry and differential scanning calorimetry), spectroscopic (vacuum infrared spectroscopy) and electrical (impedance spectroscopy) methods were used synergistically. The research results indicate that particle size affects the ionic conductivity of zeolites (1.97 & times; 10-5 S cm-1 for & micro;-FAU compared with 3.00 & times; 10-7 S cm-1 for n-FAU under dry conditions), as continuous channels in larger zeolite particles provide more efficient charge transfer pathways. Another important factor for the electrical properties of zeolites is relative humidity, or the degree of hydration, which causes a 4 order of magnitude change in ionic conductivity (3.00 & times; 10-7 S cm-1versus 2.75 & times; 10-3 S cm-1 for n-FAU under dry and humid conditions). This study demonstrates that the electrical characteristics of zeolites are highly tuneable, which may create new opportunities for the use of these porous functional materials in future sustainable applications.

Molecule-based crystals that respond to environmental stimuli such as light, temperature, pressure, electricity and humidity are attractive candidates for smart materials, i.e. sensors, actuators, optoelectronic devices, information storage, medical applications, etc. The design strategies for stimuli-responsive molecular materials are based on the interplay between weaker intermolecular interactions and flexible constituent units, e.g. pseudo-spherical organic cations and halogenometalate anions. In this context, solid-state structural transformations of a metal complex containing a natural alkaloid with a quasi-spherical fragment, the cinchoninium-trichloro-cobalt(ii), were investigated under the influence of various stimuli. The cinchoninium-trichloro-cobalt(ii) complex was dynamically modified post-synthetically by exposing it to (i) different small molecules in the vapour phase (water, methanol, acetonitrile, hydrochloric acid) or (ii) grinding conditions with small molecules (mechanochemical reaction), resulting in six different crystal phases. The structural transformations, their reversibility and selectivity towards small molecules were investigated by a combination of vacuum infrared spectroscopy and powder X-ray diffraction methods, supported by single-crystal X-ray diffraction analysis. The study of the effects of exposure to solvent molecules either in the vapour phase or by post-synthetic grinding on the crystal structure of the final product provided insights into the control of crystallographic symmetry (enhancement or breaking) and an understanding of the origin of the resistive sensing and static magnetic properties in the cinchonine-chloro-cobalt(ii) system.

We demonstrate a systematic application of the mechanochemical liquid-assisted grinding (LAG) methodology to screen for forms of zinc imidazolate (ZnIm2), of fundamental importance as the simplest member of the zeolitic imidazolate framework materials family. The exploration of 45 different liquid additives, selected based on their molecular structure and physicochemical properties has resulted in eight different ZnIm2 topological forms, appearing in 13 crystallographically distinct solid forms (including two previously unknown forms of the crb (BCT) topology), amorphous phases, and the interrupted moc-Zn4Im8HIm. All prepared topological forms were also explored computationally, using dispersion-corrected periodic density functional theory (DFT) calculations, enabling the rationalization of screening outcomes, and setting the stage for future prediction of additive-directed metal-organic framework (MOF) synthesis. This first systematic exploration of LAG in screening for three-dimensional MOFs demonstrates the potential of the liquid additive to not only accelerate materials synthesis, but also to direct it toward topologically different MOFs. The discovery of novel forms of a material that already exhibits at least 21 crystallographically and functionally different forms provides a strong testimony on the power of mechanochemistry in metal-organic materials discovery.

Two different synthesis methods to obtain hierarchical Beta zeolite are investigated: direct synthesis using cetyltrimethylammonium bromide (CTAB) as a mesoporous template and post-synthesis desilication by etching with NaOH and TPAOH. The main focus of this study is to show the possibility of fine tuning of the acid site (OH) strength (Brønsted and Lewis acid sites) through wet impregnation of these hierarchical Beta zeolites with divalent metal cations (Mg2+, Co2+, Ni2+, Cu2+, and Zn2+), which are important for various applications. Fourier transform infrared spectroscopy (FTIR) and deuterated acetonitrile as the probe molecule were used as a powerful technique to analyze the quantity and number of Brønsted/Lewis acid sites in the modified zeolite Beta structure. Investigating the influence of different divalent metal cations with a comparable ionic radius on the acidity of the hierarchical Beta zeolites, the present research aims to shed light on the structure–activity relationship that determines their catalytic behavior, for the development of efficient and environmentally friendly catalysts for various industrial applications.

Due to soft crystal packing driven by non-covalent interactions 3-quinuclidinone cations and (CoCl 4 ) 2– anions self-assemble along the preferred crystallographic orientation and form homogeneous thin films with switchable ferroelectric properties.

Capturing CO2 at low concentrations is essential for mitigating indoor air pollution and meeting the increasing demand for effective carbon capture technologies in environments where even trace levels of CO2 can significantly impact human health. This study introduces preparation of novel Zn(II)-based metal-organic framework, NICS-24, featuring diaminotriazole and oxalate linkers which form two types of square-shaped channels. NICS-24 was compared with compositionally related triazolate oxalate (CALF-20) and aminotriazolate oxalate (CALF-15) materials to evaluate the impact of amino functions on CO2 capture capabilities. While CALF-20 showed the highest CO2 uptake at 1 bar, NICS-24 excelled in capturing CO2 at low partial pressures, achieving 1.2 mmol/g at 2 mbar. The presence of amine functions in NICS-24 significantly enhanced CO2 binding and improved selectivity over N2 and O2, driven by narrower pores in comparison to CALF-20. In humid environment, NICS-24 maintained its structural integrity but exhibited reduced CO2 capture performance. In-depth investigation into CO2 adsorption mechanism under humid conditions was conducted, through the aspects of sorption breakthrough experiments, atomistic NMR studies and DFT computational approach. Competitive adsorption mechanism is in favour to water due to the specific framework hydrogen-bonding interactions. Gained understanding of the interaction between CO2 and water within the MOF framework could guide the modification via rational design with improved performance under real-world condition.

Acid catalysis is recognised as the most reliable industrial ì way to convert hydrocarbons into various products (methanol to olefins and aromatics, glycerol to olefins, methane dehydroaromatization, isomerization, etc.). In this concern, ZSM-5 is extensively used, also because of peculiar type of active sites of such zeolite. In this paper, a fine tuning of the acidity content and strength of ZSM-5 was investigated through a combination of post -synthesis treatments: desilication via alkaline solution and wet impregnation with Mg2+ ions followed by calcination. Results show that the insertion of Mg2+ has a large influence on the distribution and strength of Bronsted and Lewis acid sites of the hierarchical ZSM-5, as well as an improved crystallinity with respect to the desilicated-one. The hierarchical ZSM-5 zeolite incorporating Mg-species was tested in Methanol-to-olefins re-action and the reduction of acid strength of catalyst increased the selectivity toward light olefins (mainly pro-pylene) as well as it suppressed oligomerisation reactions delaying the coke formation.

A complex salt of tetraethylammonium cations and anions consisting of an inorganic {V4O8} core chelated with l-tartaric acid undergoes structural transformations triggered by changes in humidity and temperature, giving rise to switchable properties.

The number and the strength of acid sites in catalysts have paramount importance on their efficiency. In zeolites chemistry, increased content of framework Al in zeolites gives a higher number of strong acid sites. Their strength can be a disadvantage in catalytic reactions (e.g., methanol to olefins conversion) due to undesired secondary reactions of coke formation. Here, the Faujasite type of zeolite with higher content of Al has been used for investigating the role of defects in structure and inserted (wet impregnation and thermal treatment) metal cations (Mg, Co, Ni, Zn) on the strength of OH acid sites. Desorption of deuterated acetonitrile, as a probe molecule, was used for OH groups acid strength measurements at different temperatures (150, 200, and 300 °C).

Complex salts of DABCO- and ABCO-based cations and bis(oxalato)chromium( iii ) anions, prepared by a simple and environmentally friendly approach, exhibit stimuli-responsive structural transformations involving desolvation and resolvation processes.

This work brings into focus the superior coordination properties and facile applicability of amino acid hydrazide ligands for the design of molecular magnets and molecular ferroelectrics.

Two new coordination polymers composed of dipeptide ligand, glycyl-L-phenylalanine (Gly-L-Phe) and zinc or cadmium ions were synthesized, M(Gly-L-Phe)2 (M=Zn, Cd). Their structures were determined from powder diffraction data and it was found that they are composed of two interpenetrated coordination networks. It is the first example of such structures within the metal-dipeptide class of metal-organic frameworks (MOFs). Synthesized compounds were characterized with infrared spectroscopy, thermal and elemental analysis. Parameters of synthesis were systematically investigated and optimized. Solvothermal synthesis was tried with other metals but without positive outcome. Synthesis was also done by mechanochemical method and it gave the same compounds M(Gly-L-Phe)2 (M=Zn, Cd) but in much shorter time. In second part of thesis, mechanochemical synthesis of ZIF-8 (porous MOF) was monitored by in situ real time synchrotron X-ray diffraction. It was found that milling of ZnO and 2-methylimidazole, with addition of solution of acetic acid, produces ZIF-8 in very short time. By further milling, ZIF-8 becomes amorphous and then recrystallizes into new metastable intermediate phase which, on further milling, transforms to third ZIF-8 polymorph. New polymorph doesn't appear in every repeated reaction which is due to stochastic processes of nucleation from amorphous matrix. Added crystalline silicon as internal diffraction standard makes possible to quantify mechanochemical reaction.