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Crystal-to-crystal investigations of highly thermally stable three-dimensional coordination polymer based on sodium(I) ions and 4,4’-stilbenedicarboxylic acid

Groszek Marcin, Łyszczek Renata, Ostasz Agnieszka, Vlasyuk Dmytro

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 4

art. no. 172683

EN

The new three-dimensional coordination polymer termed {[Na2SDC(H2O)]} n (SDC2-= C16H10O42-) has been synthesized using workstation Easymax 102 while controlling the conditions and monitoring in-situ reagents. The metal complex was obtained in the reaction of sodium hydroxide with a suspension of 4,4’-stilbenedicarboxylic acid in aqueous medium. The compound was characterized by elemental analysis, single crystal, and powder X-ray diffraction methods, ATR-FTIR spectroscopy, SEM and optical microscopy, TG-DSC and TG-FTIR thermal analysis in air and nitrogen atmosphere. In the crystal structure of {[Na2SDC(H2O)]} n appears penta- and hexacoordinated sodium atoms joined by octa- and decadentate SDC2- linkers. Aqua ligand acts as bridge between Na1 and Na2 atoms. The as-synthesized sodium complex is thermally stable up to 86°C whereas its dehydrated form has extreme stability up to 491°C. Removal of water molecule leads to the crystal-to-crystal transformation yielded changes in coordination modes of COO groups. Reversibility of the hydration process in the studied complex was also examined.

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Struktura i właściwości fizykochemiczne polimerów koordynacyjnych oraz materiałów typu MOF kadmu(II) i cynku(II)

Pobłocki Kacper, Drzeżdżon Joanna, Jacewicz Dagmara

Wiadomości Chemiczne

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2021

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[Z] 75, 7-8

1041--1073

EN

In 1964, J.C. Bailat Jr. was one of the first scientists who use coordination polymers in his research. He established the rules of structure and the composition of compounds containing metal ions and organic ligands connected by coordination bonds to form layered or chain structures. He compared inorganic compounds belonging to polymeric species with organic polymers. The term Metal Organic Frameworks (MOF) was first used in the publication by О. M. Yaghia. Crystalline, microporous structures contain rigid organic ligands (used interchangeably: organic building blocks) that bind metal ions. This is called reticular synthesis. MOF surface area values usually range from 1000 to 10000 m2/g-1, thus exceeding the area values of traditional porous materials such as zeolites and carbons. Metal Organic Frameworks create porous three-dimensional structures, unlike coordination polymers. Inorganic minerals from the aluminosilicate group are used in the widespread heterogeneous catalysis and processes such as: adsorption and ion exchange, while compared to Metal Organic Frameworks, shows a lower potential than zeolites, moreover, the design of structures is less precise and rational due to the lack of shape, size and control functionalization of pores. To date, MOF are the most diverse and most numerous class of porous materials. All aspects have made them ideal structures for storing fuels such as hydrogen and methane. They are perfect for catalytic reactions and are good materials for capturing pollutants, e.g. CO2. The number of publications on coordination polymers (CP), Metal Organic Frameworks (MOF) or a group of hybrid compounds (organic-inorganic) increased tenfold at the turn of 2005, which proves the growing interest in this field by scientists around the world. MOF diversity in terms of structure, size, geometry, functionality and flexibility of MOF has led to the study of over 20,000 different MOF’s over the past decade. The search for new materials consists of combining molecular building blocks with the desired physicochemical properties. To produce a solid, porous material that can be used in the construction of a "molecular scaffold", rigid organic moieties, which are described in the literature as rods, must be combined with multi-core, inelastic inorganic clusters that act as joints (also called SBU secondary building units). By design, multi-core cluster nodes are able to impart thermodynamic stability through strong covalent bonds and mechanical stability due to coordination bonds that can stabilize the position of metals in the molecule. This property contrasts with those of the unstable single coordination polymers. The size and most importantly the chemical environment of the resulting voids are determined by the length and functions of the organic unit. Therefore, adjusting the appropriate properties of the material is made by appropriate selection of the starting materials. The isoretical method made it possible to use MOF structures with large pores (98 Á and low densities (0.13 g/cm3). This method involves changing the size and nature of Metal Organic Frameworks without changing the topology of their substrate. Thanks to this, it was possible to include large molecules such as vitamins (e.g. B12) or proteins (e.g. green fluorescence protein) into their structure and use the pores as reaction vessels. The thermal and chemical stability of many MOFs has made them amenable to functionalization by post-synthetic covalent organic complexes with metals. These properties make it possible to significantly improve gas storage in MOF structures and have led to their extensive research into the catalysis of organic reactions, activation of small molecules such as hydrogen, methane and water, gas separation, biomedical imaging and conductivity. Currently, methods of producing nanocrystals and MOF super crystals for their incorporation into specialized devices are being developed. Crystalline structures of MOF’s are formed by creating strong bonds between inorganic and organic units. Careful selection of MOF components produces crystals of giant porosity, high thermal and chemical stability. These features allow the interior of the MOF to be chemically altered to separate and store gases. The uniqueness of MOF materials is that they are the only solids to modify and increase the particle size without changing the substrate topology.

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Sieci metalo-organiczne jako multifunkcjonalne materiały przyszłości : mechanochemiczne podejście do syntezy

Jędrzejowski D.

Wiadomości Chemiczne

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2018

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[Z] 72, 9-10

645--666

EN

Metal-organic frameworks (MOFs) are a relatively new class of advanced inorganic-organic materials. Due to their modular structures and possible incorporation of various properties, that materials find more and more applications in many fields of science and industry. MOFs are coordination polymers, i.e. compounds with coordination bonds propagating infinitely in at least one dimension. Their characteristic feature is the presence of potential free spaces, i.e. pores. The free spaces often appear after proper activation, e.g. thermal activation. Other common properties of MOFs include for instance large specific surface areas and pore volumes, modifiable size and chemical environment of the pores, and network flexibility. All these properties result in the use of MOFs in e.g. selective sorption, separation or storage of gases, heterogeneous catalysis, design and fabrication of sensors, etc. During more than twenty years of the history of MOFs, many methods of their synthesis have been developed, including the most popular in solution at elevated temperatures (e.g. solvothermal method). Nevertheless, the activity of pro-ecological environments and the requirements set by international organizations encourage scientists to create new methods of synthesis, which, according to the guidelines presented by the 12 principles of green chemistry, will be safer, less aggressive, less toxic and less energy-consuming. One of the answers to meet these requirements is the use of mechanosynthesis. Mechanochemical synthesis relies on the supply of energy to a system by mechanical force, by grinding or milling. By combining or transforming solids in this way, the presence of a solvent, which is most often the main source of contamination and waste, can be minimised or completely excluded. Mechanical force is typically used for purposes other than MOF synthesis, e. g. catalyst grinding. Nevertheless, the use of mechanical force in synthesis is becoming more and more popular. The most important advantages of this approach, apart from its environmental impact, are very high efficiency (usually close to 100%) and drastically reduced reaction time. Of course, there are examples where these advantages are not observed. In such cases, mechanosynthetic modifications are introduced, such as e.g. addition of small amount of liquid (Liquid-Assisted Grinding) and/or a small addition of simple inorganic salt (Ion- and Liquid-Assisted Grinding). Furthermore, new instrument setups are being developed to monitor reaction mixtures in situ during mechanosynthesis, e.g. by use of such techniques as powder X-ray diffraction and Raman spectroscopy. This enables valuable insights into mechanisms and allows for mechanosynthesis optimization.

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Flexible magnetic coordination networks sensitive to guest molecules

Heczko M., Nowicka B.

Journal of Education and Technical Sciences

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2015

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Vol. 2, nr 1

19--21

EN

Structurally flexible coordination networks that react to different external stimuli with structure deformation, and consequently changes in magnetic properties, are potential candidates for molecular switches and sensors. The design of guest-sensitive molecular magnetic materials based on the specific building blocks: [Ni(cyclam)]2+ (cyclam = 1,4,8,11-tetraazacyclotetradecane) cation and polycyanometallate anions is discussed. The examples of different dimensionality networks and the changes in their structure and magnetic properties in response to sorption of small molecules are presented.

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Thallium I phenylsuccinic acid coordination polymer as precursor for preparation of thallium (III) oxide nano structures by direct thermal decomposition

Soltanian M J, Tabaroki S

Materials Science Poland

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2014

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Vol. 32, No. 1

23--27

EN

A new thallium (I) coordination polymer [Tl(PsucH)]n (PsucH = phenylsuccinic acid) has been synthesized and characterized by single crystal X-Ray analysis, elemental analysis and IR spectroscopy. The single crystal X-Ray analysis shows that this polymer is 2-D along a axis. Flower-like nanostructure thallium (III) oxide, Tl2O3 has been prepared by direct thermal decomposition of thallium (I) coordination polymer. The nanostructure was characterized by scanning electron microscopy (SEM), X-Ray powder diffraction (XRD) and IR spectroscopy. The thermal stability of the Tl2O3 nanostructure was studied by thermal gravimetric analysis and differential thermal analysis (TGA /DTA) too.