ANDROID APPLICATION FOR USER’S REAL-TIME INFORMATION REGARDING THE POSIBILITY OF BEING CONTACT TO A COVID-19 INFECTED PERSON

Soon after the pandemic inflicted by Covid-19 was declared, different organizations and smart application development companies suggested that artificial intelligence could be an useful tool in helping the medical staff monitoring the virus spread for a better understanding of its behavior. This paper presents a smart application CovidWatch developed for users real-time warning regarding the possibility of contracting the Sars-CoV-2 virus from an infected person. For this purpose, the developed application uses the Bluetooth module of the user’s device in order to check the social distance and to determine the possible contacts. The developed application has a number of four modules (the expert system (ES), the data retrieval, the real-time information and warning and the interface), that work on Android devices. Using the artificial intelligence techniques (knowledge-based systems), the application has a knowledge base populated with user’s data, the user’s time of contact and distance and the users identified as being contacts. If a user warns the android application that he has been infected with Covid-19, it further triggers the expert system inference engine, allowing the knowledge to be inferred. Based on the implemented rules, the inference engine analyses the data regarding the users that were in contact with an infected person. If those meet the conditions taken into consideration for declaring a person as being contact (a certain distance and time) they receive in real time a warning message and some advice regarding how it is recommended to act. The main advantage of android application is that it provides real-time warning regarding the possibility or probability of being infected with Covid-19, warning that can be deactivated only after the user has confirmed that the took note of this. A set of CovidWatch application simulation results is also presented taking into consideration different scenarios

Zeolite-like metal–organic frameworks (ZMOFs): design, synthesis, and properties

International audienceThis review highlights various design and synthesis approaches toward the construction of ZMOFs, which are metal-organic frameworks (MOFs) with topologies and, in some cases, features akin to traditional inorganic zeolites. The interest in this unique subset of MOFs is correlated with their exceptional characteristics arising from the periodic pore systems and distinctive cage-like cavities, in conjunction with modular intra-and/or extra-framework components, which ultimately allow for tailoring of the pore size, pore shape, and/or properties towards specific applications

catena-Poly[zinc-tris­(μ-dimethyl­carbamato-κ2 O:O′)-zinc-μ-(2-phenyl­benzimidazolido-κ2 N:N′]

The crystal structure of the title compound, [Zn2(C13H9N2)(C3H6NO2)3]n, displays a long chiral chain. This is composed of zinc-dimer clusters capped by dimethyl­carbamate ligands, which lie on crystallographic twofold rotation axes and are polymerically linked in one dimension by 2-phenyl­benzimidadole (2–PBImi) organic ligands. The two Zn2+ ions defining the dimetal cluster are crystallographically independent, but display very similar coordination modes and tetra­hedral geometry. As such, each Zn2+ ion is coordinated on one side by the N-donor imidazole linker, while the other three available coordination sites are fully occupied by the O atoms from the capping dimethyl­carbamates. The chirality of the chain extends along the c axis, generating a rather long 52.470 (11) Å cell axis. Inter­estingly, the chiral material crystallizes from completely achiral precursors. A twofold axis and 31 screw axis serve to generate the long asymmetric unit

Quest Towards the Design and Synthesis of Functional Metal-Organic Materials: A Molecular Building Block Approach

The design of functional materials for specific applications has been an ongoing challenge for scientists aiming to resolve present and future societal needs. A burgeoning interest was awarded to developing methods for the design and synthesis of hybrid materials, which encompass superior functionality via their multi-component system. In this context, Metal-Organic Materials (MOMs) are nominated as a new generation of crystalline solid-state materials, proven to provide attractive features in terms of tunability and versatility in the synthesis process. In strong correlation with their structure, their functions are related to numerous attractive features, with emphasis on gas storage related applications. Throughout the past decade, several design approaches have been systematically developed for the synthesis of MOMs. Their construction from building blocks has facilitated the process of rational design and has set necessary conditions for the assembly of intended networks. Herein, the focus is on utilizing the single-metal-ion based Molecular Building Block (MBB) approach to construct frameworks assembled from predetermined MBBs of the type MNx(CO2)y. These MBBs are derived from multifunctional organic ligands that have at least one N- and O- heterochelate function and which possess the capability to fully saturate the coordination sphere of a single-metal-ion (of 6- or higher coordination number), ensuring rigidity and directionality in the resulting MBBs. Ultimately, the target is on deriving rigid and directional MBBs that can be regarded as Tetrahedral Building Units (TBUs), which in conjunction with appropriate heterofunctional angular ligands are capable to facilitate the construction of Zeolite-like Metal-Organic Frameworks (ZMOFs). ZMOFs represent a unique subset of MOMs, particularly attractive due to their potential for numerous applications, arising from their fully exploitable large and extra-large cavities. The research studies highlighted in this dissertation will probe the validity and versatility of the single-metal-ion-based MBB approach to generate a repertoire of intended MOMs, ZMOFs, as well as novel functional materials constructed from heterochelating bridging ligands. Emphasis will be put on investigating the structure-function relationship in MOMs synthesized via this approach; hydrogen and CO2 sorption studies, ion exchange, guest sensing, encapsulation of molecules, and magnetic measurements will be evaluated

Quest Towards the Design and Synthesis of Functional Metal-Organic Materials: A Molecular Building Block Approach

The design of functional materials for specific applications has been an ongoing challenge for scientists aiming to resolve present and future societal needs. A burgeoning interest was awarded to developing methods for the design and synthesis of hybrid materials, which encompass superior functionality via their multi-component system. In this context, Metal-Organic Materials (MOMs) are nominated as a new generation of crystalline solid-state materials, proven to provide attractive features in terms of tunability and versatility in the synthesis process. In strong correlation with their structure, their functions are related to numerous attractive features, with emphasis on gas storage related applications. Throughout the past decade, several design approaches have been systematically developed for the synthesis of MOMs. Their construction from building blocks has facilitated the process of rational design and has set necessary conditions for the assembly of intended networks. Herein, the focus is on utilizing the single-metal-ion based Molecular Building Block (MBB) approach to construct frameworks assembled from predetermined MBBs of the type MNx(CO2)y. These MBBs are derived from multifunctional organic ligands that have at least one N- and O- heterochelate function and which possess the capability to fully saturate the coordination sphere of a single-metal-ion (of 6- or higher coordination number), ensuring rigidity and directionality in the resulting MBBs. Ultimately, the target is on deriving rigid and directional MBBs that can be regarded as Tetrahedral Building Units (TBUs), which in conjunction with appropriate heterofunctional angular ligands are capable to facilitate the construction of Zeolite-like Metal-Organic Frameworks (ZMOFs). ZMOFs represent a unique subset of MOMs, particularly attractive due to their potential for numerous applications, arising from their fully exploitable large and extra-large cavities. The research studies highlighted in this dissertation will probe the validity and versatility of the single-metal-ion-based MBB approach to generate a repertoire of intended MOMs, ZMOFs, as well as novel functional materials constructed from heterochelating bridging ligands. Emphasis will be put on investigating the structure-function relationship in MOMs synthesized via this approach; hydrogen and CO2 sorption studies, ion exchange, guest sensing, encapsulation of molecules, and magnetic measurements will be evaluated

Poly[guanidinium [tri-μ-formato-κ6O:O′-formato-κ2O,O′-yttrium(III)]]

In the title coordination polymer, {(CH6N3)[Y(CHO2)4]}n, the yttrium(III) ion is coordinated by one O,O-bidentate formate ion and six μ2 bridging formate ions, generating a square-antiprismatic YO8 coordination polyhedron. The bridging formate ions connect the metal ions into an anionic, three-dimensional network. Charge compensation is provided by guanidinium ions, which interact with the framework by way of N—H...O hydrogen bonds. The guanidine molecules reside in porous channels of 3.612 by 8.189 Å, when considering the van der Waals radii of the nearest atoms (looking down the a-axis)

Single-Metal-Ion-Based Molecular Building Blocks (MBBs) Approach to the Design and Synthesis of Metal-Organic Assemblies

The single-metal-ion-based molecular building blocks (MBBs) approach for the construction of metal–organic assemblies, in which hetero-coordinated single metal ions are rendered rigid and directional via nitrogen–oxygen chelation with judiciously selected ligands, has been implemented. Single-metal-ion-based MBBs of the general formula MNx(CO2)y constitute the building units of metal–organic frameworks (MOFs) and metal–organic polyhedra (MOPs) presented herein. The octahedral MBB, MN2(CO2)4, can occur as two structural isomers depending on the positioning of nitrogen atoms. The MN2(CO2)4 MBBs contain two rings of heterochelation, and depending on the position of the oxygen atoms involved in heterochelation it is possible to generate three different building units (BUs) from the cis-MN2(CO2)4 MBB and two BUs from the trans-MN2(CO2)4 MBB. Assembly of the different BUs derived from the cis-MN2(CO2)4 MBB, through a bifunctional ligand such as 2,5-pyridinedicarboxylic acid, permits the construction of diverse assemblies, such as a metal–organic 2D Kagomé lattice, a discrete octahedron, and a 3D diamondoid-like network. The fac-MN3(CO2)3 MBB mediates a BU with the appropriate geometry to facilitate the formation of a metal–organic cube, and the BU resulting from the mer-MN3(CO2)3 MBB is T-shaped. Tetrahedral building units (TBUs) can be derived either from MN4(CO2)2 or MN4(CO2)4 MBBs, from which zeolite-like MOFs have been constructed. Foremost, rationalization and systemization of such findings offer great potential toward the pursuit of the logical synthesis of functional metal–organic assemblies

Harnessing Particle Size‐Control and DNA‐Oligo Functionalization in ZIF‐76 for Biological Applications

Abstract Advanced therapeutics require novel nanocarriers to ensure their functionality is preserved during transit. Zeolitic imidazolate frameworks (ZIFs) have emerged as promising materials in this field owing to their combined biocompatibility, high porosity, and tunable chemistry. While a diverse family of ZIFs has been reported, few have been explored beyond the prototypical ZIF‐8. Herein, the size‐controlled synthesis of three distinct ZIF‐76 analogs is demonstrated, overcoming the unique synthetic challenges intrinsic to the lta topology and complex crystallization kinetics associated with the mixed linker approach. This assesses the materials’ platform effectiveness for intracellular delivery first by exploring the structural and colloidal stability in biologically relevant media. To circumvent particle aggregation, fluorescently labeled DNA oligonucleotides are post‐synthetically attached to the ZIF surface. This modification significantly improves the colloidal stability in media and facilitates particle internalization tracking. Finally, the particle‐cell interactions are assessed, revealing rapid cell membrane association with macrophages, but not lung epithelial cells, and ZIF accumulation within macrophages which increased over time. Importantly, this study outlines a generalized approach toward expanding the available library of ZIFs for biological applications, enabling the potential for targeted therapeutic delivery for intracellular infections treatment

4,4′-([4,4′-Bipyridine]-1,1′-diium-1,1′-diyl)dibenzoate dihydrate

We report here the synthesis of a neutral viologen derivative, C24H16N2O4·2H2O. The non-solvent portion of the structure (Z-Lig) is a zwitterion, consisting of two positively charged pyridinium cations and two negatively charged carboxylate anions. The carboxylate group is almost coplanar [dihedral angle = 2.04 (11)°] with the benzene ring, whereas the dihedral angle between pyridine and benzene rings is 46.28 (5)°. The Z-Lig molecule is positioned on a center of inversion (Fig. 1). The presence of the twofold axis perpendicular to the c-glide plane in space group C2/c generates a screw-axis parallel to the b axis that is shifted from the origin by 1/4 in the a and c directions. This screw-axis replicates the molecule (and solvent water molecules) through space. The Z-Lig molecule links to adjacent molecules via O—H...O hydrogen bonds involving solvent water molecules as well as intermolecular C—H...O interactions. There are also π–π interactions between benzene rings on adjacent molecules

Adapting UFF4MOF for Heterometallic Rare-Earth Metal–Organic Frameworks

Heterometallic metal–organic frameworks based on rare-earth metals (RE-MOFs) have potential in a number of applications where energy transfer between nearby metal atoms is required. This observation implies that it is important to understand the level of local mixing that is achieved between metals of different types during synthesis of RE-MOFs. Density functional theory calculations can give quantitative information on the relative energy of different configurations of RE-MOFs, but these calculations cannot be applied to the full range of medium- and long-range orderings that are possible in heterometallic materials. This limitation can be overcome using force field (FF)-based calculations if appropriate FFs are available. We show that an existing generic FF for MOFs, UFF4MOF, does not accurately predict energies of mixing in heterometallic Nd/Yb MOFs and introduce a modified FF to address this shortcoming. The resulting FF is used to explore metal orderings in large simulation volumes for a Nd/Yb MOF, illustrating the complexities that can arise in the structure of heterometallic RE-MOFs