Dibromido{N′-[1-(pyridin-2-yl)ethyl­idene]picolinohydrazide-κ2 N′,O}cadmium

The title compound, [CdBr2(C13H12N4O)], was obtained from the reaction of Cd(NO3)2·4H2O with meth­yl(pyridin-2-yl)methanone picolinoylhydrazone and sodium bromide. The Cd2+ cation is ligated by one O atom and two N atoms of the tridentate ligand and two bromide anions, forming a Br2CdN2O polyhedron with a distorted trigonal–bipyramidal coordination geometry. In the crystal, non-classical C—H⋯Br hydrogen bonds are observed. In addition, π–π stacking inter­actions [centroid–centroid distance = 3.7455 (19) Å] contribute to the stabilization of the crystal structure

New insight in severe acute respiratory syndrome coronavirus 2 consideration: Applied machine learning for nutrition quality, microbiome and microbial food poisoning concerns

Although almost two years have passed since the beginning of the coronavirus disease 2019 (COVID-19) pandemic in the world, there is still a threat to the health of people at risk and patients. Specialists in various sciences conduct various researches in order to eliminate or reduce the problems caused by this disease. Nutrition is one of the sciences that plays a very important supportive role in this regard. It is important for patients to pay attention to the potential of different diets in preventing or accelerating the healing process. The relationship between nutrition and microbiome regulation or the occurrence of food microbial poisoning is one of the factors that can directly or indirectly play a key role in the body's resilience to COVID-19. In this article, we introduce a link between nutrition, the microbiome, and the incidence of food microbial poisoning that may have great potential in preventing, treating COVID-19, or preventing deterioration in patients. In linking the components of this network, artificial intelligence (AI), machine learning (ML) and data mining (DM) can be important strategies and lead to the creation of a conceptual model called "Balance square", which we will introduce

Structural versatility of the quasi-aromatic Möbius type zinc(II)-pseudohalide complexes : experimental and theoretical investigations

In this contribution we report for the first time fabrication, isolation, structural and theoretical characterization of the quasi-aromatic Mobius complexes [Zn(NCS)(2)L-I] (1), [Zn-2(mu(1,1)-N-3)(2)(L-I)(2)][ZnCl3(MeOH)](2)center dot 6MeOH (2) and [Zn(NCS)L-II](2)[Zn(NCS)(4)]center dot MeOH (3), constructed from 1,2-diphenyl-1,2-bis((phenyl(pyridin-2-yl)methylene)hydrazono)ethane (L-I) or benzilbis(acetylpyridin-2-yl)methylidenehydrazone (L-II), respectively, and ZnCl2 mixed with NH4NCS or NaN3. Structures 1-3 are dictated by both the bulkiness of the organic ligand and the nature of the inorganic counter ion. As evidenced from single crystal X-ray diffraction data species 1 has a neutral discrete heteroleptic mononuclear structure, whereas, complexes 2 and 3 exhibit a salt-like structure. Each structure contains a Zn-II atom chelated by one tetradentate twisted ligand L-I creating the unusual Mobius type topology. Theoretical investigations based on the EDDB method allowed us to determine that it constitutes the quasi-aromatic Mobius motif where a metal only induces the pi-delocalization solely within the ligand part: 2.44|e| in 3, 3.14|e| in 2 and 3.44|e| in 1. It is found, that the degree of quasi-aromatic pi-delocalization in the case of zinc species is significantly weaker (by similar to 50%) than the corresponding estimations for cadmium systems - it is associated with the Zn-N bonds being more polar than the related Cd-N connections. The ETS-NOCV showed, that the monomers in 1 are bonded primarily through London dispersion forces, whereas long-range electrostatic stabilization is crucial in 2 and 3. A number of non-covalent interactions are additionally identified in the lattices of 1-3

Modulation of coordination in pincer-type isonicotinohydrazone Schiff base ligands by proton transfer

We present here two different coordination polyhedra of pincer type N2O hydrazone based ligands supplemented with thiocyanate ions. The compounds namely [Hg(SCN)2(HL1)] (1) and [Hg(SCN)2(HL2)] (2) have a common isonicotinohydrazone fragment and have been prepared by using a coordination driven self-assembly of the Hg(SCN)2 with two different ligands including 2-benzoylpyridine-isonicotinoylhydrazone (HL1), and 2-acetylpyridineisonicotinoylhydrazone (HL2). In compound 1 the ligand coordinated to the mercury center in the keto form (=N–NH=C=O) whereas, in compound 2, the proton at the hydrazine group have been shifted to the uncoordinated pyridine ring and the ligand acted as a zwitterion. The structures provide a complementary system for proton transfer within the ligand molecule involving the keto-enol tautomerization of amide group and 4-pyridyl N protonation. As a result, the relative location of orbitals and ligands in the complexes are different as well as the bonding strength and the coordination polyhedra. We have also studied electrostatically enhanced π···π (either conventional or involving the chelate ring) interactions observed in the solid state of both compounds and analyzed them using DFT calculations, Molecular Electrostatic Potential surface and the Bader’s theory of atoms in molecules

Lead(II) coordination polymers driven by pyridine-hydrazine donors : from anion-guided self-assembly to structural features

In this work, we report extensive experimental and theoretical investigations on a new series of PbII coordination polymers exhibiting extended supramolecular architectures, namely [Pb2(LI)(NCS)4]n (1), [Pb(HLII)I2]n (2), [Pb(LIII)I]n (3) and [Pb(HLIV)(NO3)2]n·nMeOH (4), which were self-assembled from different PbII salts and various pyridine-hydrazine based linkers, namely 1,2-bis(pyridin-3-ylmethylene)hydrazine (LI), (pyridin-4-ylmethylene)isonicotinohydrazide (HLII), 1-(pyridin-2-yl)ethylidenenicotinohydrazide (HLIII) and phenyl(pyridin-2-yl)methylenenicotinohydrazide (HLIV), respectively. It is recognized that the origin of self-assembling is fundamentally rooted in a dual donor (6s2/6p0 hybridized lone electron pair) and electrophilic behaviour of PbII. This allows production of extended topologies from a 1D polymeric chain in 4 through a 2D layer in 2 to the 3D frameworks in 1 and 3, predominantly due to the cooperative action of both covalent and non-covalent tetrel interactions of the overall type Pb-X (X = O, N, S, I). Counterintuitively, the latter, seemingly weak interactions, have appeared to be even stronger than the typical covalent bonds due to the presence of a bunch of supportive London dispersion dominated contacts: ππ, Lpπ, C-HO, C-HI, C-HH-C as well as more typical mainly electrostatically driven N-HO or N/O-HO hydrogen bonds. It is revealed that the constituting generally strong tetrel type Pb-X (X = O, N, S, I) bonds, though dominated by a classic Coulomb term, are therefore characterized by a very important London dispersion constituent, extremely strong relativistic effects and the two way dative-covalent Pb ↔ X electron charge delocalization contribution as revealed by the Extended Transition State Natural Orbital for Chemical Valence (ETS-NOCV) charge and energy decomposition scheme. It unravels that the pyridine-hydrazine linkers are also excellent London dispersion donors, and that together with the donor-acceptor properties of the heavy (relativistic) PbII atoms and nucleophilic counterions lead to extended self-assembling of 1-4

Di-mu-chlorido-bis(chlorido{N '-[phenyl(pyridin-2-yl-kappa N)methylidene]pyridine-2-carbohydrazide-kappa N-2 ',O}cadmium)

The title compound, [Cd2Cl4(C18H14N4O)(2)], was obtained from the reaction of Cd(NO3)(2)center dot 4H(2)O with 2-phenylpyridine-keton picolinoyl hydrazone and sodium chloride. Each Cd2+ cation is coordinated by two N atoms and one O atom of the tridentate ligand and three chloride anions, forming a distorted CdNOCl3 octahedron. Each pair of adjacent metal cations is linked by two bridging chloride ligands, resulting in a dinuclear complex unit. The molecular conformation is stabilized by intramolecular N-H center dot center dot center dot N and C-H center dot center dot center dot O hydrogen bonds. In the crystal, molecules are linked by nonclassical C-H center dot center dot center dot O and C-H center dot center dot center dot Cl hydrogen bonds into a three-dimensional network. In addition, pi-pi stacking interactions [centroid-centroid distances = 3.777 (2) and 3.631 (2) angstrom] contribute to the stabilization of the crystal packing

Sonochemical Synthesis of Cadmium(II) Coordination Polymer Nanospheres as Precursor for Cadmium Oxide Nanoparticles

Nanospheres of a new coordination polymer {[Cd2(µ-HL)(µ-L)(NO3)3(H2O)]·H2O}n (1) were easily prepared by a sonochemical method from cadmium(II) nitrate and HL (HL, pyridine-2-carboxaldehyde isonicotinoyl hydrazone) in ethanol. Single crystals of 1 were also obtained using a branched tube method. The crystal structure of 1 indicates that the µ-HL/µ-L− blocks act as linkers between the Cd(II) centers, assembling them into 1D tooth-shaped interdigitated chains, which are further interlinked into a complex 3D H-bonded network with a rare hms (3,5-conn) topology. Nanoparticles of 1 were characterized by elemental analysis, FT-IR spectroscopy, and powder X-ray diffraction (XPRD), while their spherical morphology was confirmed by transmission electron microscopy (TEM). Furthermore, in the presence of a surfactant, the thermolysis of sonochemically generated nanoparticles of 1 led to the formation of cadmium oxide nanospheres (cubic CdO) with an average diameter of 10 nm. This study extends the application of sonochemical synthetic methods for the generation of phase pure nanoparticles of coordination polymers and their thermolysis products

Solvent-driven azide-induced mononuclear discrete versus one-dimensional polymeric aromatic Möbius cadmium(ii) complexes of an N6 tetradentate helical ligand

We report the synthesis and structural characterization of a heteroleptic mononuclear discrete complex [Cd(N3)2(L)(MeOH)]·MeOH (1·MeOH) and a one-dimensional coordination polymer of the composition [Cd3(N3)6(L)]n (2), fabricated from Cd(NO3)2·4H2O and the helical organic ligand benzilbis((pyridin-2-yl)methylidenehydrazone) (L) in the presence of two equivalents of NaN3. The formation of different structures is driven by the solvent. The former complex is formed in the presence of MeOH, while the latter complex is formed in EtOH. The CdII centre in 1·MeOH is trapped by the two pyridyl-imine units of the tetradentate ligand L, two azide ligands and one oxygen atom of one methanol ligand with the CdN6O coordination polyhedron yielding a square face monocapped trigonal prism. The asymmetric unit of 2 consists of three symmetrically independent atoms of CdII, six azide anions and one L. The polymeric structure of 2 is realized through chains of the Cd(N3)2 units which are decorated with Cd(N3)2L units. The CdII atoms from the backbone of the coordination polymer have a distorted octahedral coordination, while the remaining CdII atom forms a trigonal prism with two basal planes nearly parallel to each other. In both complexes, the 12π electron chelate ring of the CdL fragment is shown to be aromatic by establishing it as a Möbius object. Hirshfeld surface analysis of 1 in 1·MeOH and L in 2 showed that the structures of both species are highly dominated by H⋯X (X = H, C and N) contacts, of which the latter two are highly favoured, as well as some contribution from highly enriched C⋯C contacts is clearly observed

Crystal structures of di-bromido-{ N-[(pyridin-2-yl-κ N)methyl-idene]picolinohydrazide-κ 2N', O}cadmium methanol monosolvate and di-iodido{ N-[(pyridin-2-yl-κ N)methyl-idene]picolinohydrazide-κ 2N', O}cadmium

TARAMAPUBMEDThe title compounds, [CdBr2(C12H10N4O)]·CH3OH, (I), and [CdI2(C12H10N4O)], (II), are cadmium bromide and cadmium iodide complexes of the ligand (E)-N'-(pyridin-2-yl-methyl-ene)picolinohydrazide. Complex (I) crystallizes as the methanol monosolvate. In both compounds, the Cd2+ cation is ligated by one O atom and two N atoms of the tridentate ligand, and by two bromide anions forming a Br2N2O penta-coordination sphere for (I), and by two iodide anions forming an I2N2O penta-coordination sphere for (II), both with a distorted square-pyramidal geometry. In the crystal of complex (I), mol-ecules are linked by pairs of N-H⋯O and O-H⋯Br hydrogen bonds, involving the solvent mol-ecule, forming dimeric units, which are linked by C-H⋯Br hydrogen bonds forming layers parallel to (101). In the crystal of complex (II), mol-ecules are linked by N-H⋯I hydrogen bonds, forming chains propagating along [010]. In complex (II), measured at room temperature, the two iodide anions are each disordered over two sites; the refined occupancy ratio is 0.75 (2):0.25 (2)

Structural versatility of the quasi-aromatic Möbius type zinc(ii)-pseudohalide complexes-experimental and theoretical investigations

In this contribution we report for the first time fabrication, isolation, structural and theoretical characterization of the quasi-aromatic Möbius complexes [Zn(NCS)2LI] (1), [Zn2(μ1,1-N3)2(LI)2][ZnCl3(MeOH)]2·6MeOH (2) and [Zn(NCS)LII]2[Zn(NCS)4]·MeOH (3), constructed from 1,2-diphenyl-1,2-bis((phenyl(pyridin-2-yl)methylene)hydrazono)ethane (LI) or benzilbis(acetylpyridin-2-yl)methylidenehydrazone (LII), respectively, and ZnCl2 mixed with NH4NCS or NaN3. Structures 1-3 are dictated by both the bulkiness of the organic ligand and the nature of the inorganic counter ion. As evidenced from single crystal X-ray diffraction data species 1 has a neutral discrete heteroleptic mononuclear structure, whereas, complexes 2 and 3 exhibit a salt-like structure. Each structure contains a ZnII atom chelated by one tetradentate twisted ligand LI creating the unusual Möbius type topology. Theoretical investigations based on the EDDB method allowed us to determine that it constitutes the quasi-aromatic Möbius motif where a metal only induces the π-delocalization solely within the ligand part: 2.44e in 3, 3.14e in 2 and 3.44e in 1. It is found, that the degree of quasi-aromatic π-delocalization in the case of zinc species is significantly weaker (by ∼50%) than the corresponding estimations for cadmium systems-it is associated with the Zn-N bonds being more polar than the related Cd-N connections. The ETS-NOCV showed, that the monomers in 1 are bonded primarily through London dispersion forces, whereas long-range electrostatic stabilization is crucial in 2 and 3. A number of non-covalent interactions are additionally identified in the lattices of 1-3