Theoretical and electrochemical studies on organometallic symmetrical schiff base complexes of Zn(II), Cu(II), Ni(II) and Co(II).

International audienceThe electronic communication between two redox centres through a Schiff base complex has been investigated in a series of ethylenediimine-bis(1-ferrocenyl-1,3-butanedionate) complexes of Zn(II) 1, Cu(II) 2, Ni(II) 3 and Co(II) 4. Cyclic voltammetry experiments of 1 and 2 exhibit a unique two-electron reversible oxidation wave, whereas in the case of 3 and 4 two and three one-electron oxidation processes are, respectively, observed. These results suggest some electronic interaction between the iron atoms of the ferrocenyl groups. DFT calculations carried out on model complexes show that for all the studied compounds the removal of the first two electrons corresponds to the oxidation processes of the iron centres in the weakly coupled ferrocenyl termini. The electronic communication between the two iron centres increases on going from 1 to 4. Finally, a re-indexation of the bands observed in the UV-Visible spectra has been carried out using TDDFT calculations

Di-μ-acetato-κ3 O,O′:O;κ3 O:O,O′-bis­[(acetato-κ2 O,O′)(1,10-phenan­throline-κ2 N,N′)cadmium(II)]

The title compound, [Cd2(C2H3O2)4(C12H8N2)2], consists of dimeric units built up around a crystallographic symmetry centre. Each cadmium(II) unit is chelated by a 1,10-phenanthroline (phen) group and two acetate ligands, one of which also acts as a bridge, linking both seven-coordinated cadmium(II) centres. The crystal structure is governed by a single π–π inter­action between stacked phen groups [centroid–centroid distance 3.5209 (11) Å], leading to a planar structure parallel to (010)

Transmission cluster of COVID-19 cases from Uruguay: emergence and spreading of a novel SARS-CoV-2 ORF6 deletion

BACKGROUND Evolutionary changes in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) include indels in nonstructural, structural, and accessory open reading frames (ORFs) or genes. OBJECTIVES We track indels in accessory ORFs to infer evolutionary gene patterns and epidemiological links between outbreaks. METHODS Genomes from Coronavirus disease 2019 (COVID-19) case-patients were Illumina sequenced using ARTIC_V3. The assembled genomes were analysed to detect substitutions and indels. FINDINGS We reported the emergence and spread of a unique 4-nucleotide deletion in the accessory ORF6, an interesting gene with immune modulation activity. The deletion in ORF6 removes one repeat unit of a two 4-nucleotide repeat, which shows that directly repeated sequences in the SARS-CoV-2 genome are associated with indels, even outside the context of extended repeat regions. The 4-nucleotide deletion produces a frameshifting change that results in a protein with two inserted amino acids, increasing the coding information of this accessory ORF. Epidemiological and genomic data indicate that the deletion variant has a single common ancestor and was initially detected in a health care outbreak and later in other COVID-19 cases, establishing a transmission cluster in the Uruguayan population. MAIN CONCLUSIONS Our findings provide evidence for the origin and spread of deletion variants and emphasise indels’ importance in epidemiological studies, including differentiating consecutive outbreaks occurring in the same health facility

Three isotypic polymeric complexes with rare earth cations, but-2-enoate anions and 4,4'-(ethane-1,2-diyl)dipyridine and 4,4'-(ethene-1,2-diyl)dipyridine bridging ligands

© 2015 International Union of Crystallography.Three isotypic rare earth complexes, catena-poly[[aquabis(but-2-enoato-κ2 O,O')yttrium(III)]-bis(μ-but-2-enoato)-κ3 O,O':O;κ3 O:O,O'-[aquabis(but-2-enoato-κ2 O,O')yttrium(III)]-μ-4,4'-(ethane-1,2-diyl)dipyridine-κ2 N:N'], [Y2(C4H5O2)6(C12H12N2)(H2O)2], the gadolinium(III) analogue, [Gd2(C4H5O2)6(C12H12N2)(H2O)2], and the gadolinium(III) analogue with a 4,4'-(ethene-1,2-diyl)dipyridine bridging ligand, [Gd2(C4H5O2)6(C12H10N2)(H2O)2], are one-dimensional coordination polymers made up of centrosymmetric dinuclear [M(but-2-enoato)3(H2O)]2 units (M = rare earth), further bridged by centrosymmetric 4,4'-(ethane-1,2-diyl)dipyridine or 4,4'-(ethene-1,2-diyl)dipyridine spacers into sets of chains parallel to the [20 ] direction. There are intra-chain and inter-chain hydrogen bonds in the structures, the former providing cohesion of the linear arrays and the latter promoting the formation of broad planes parallel to (010)

Hexakis(imidazole-N3)nickel(II) oxydiacetate ethanol solvate

The crystal structure of the title complex, [Ni(C3H4N2)6](C4H 4O5)·C2H5OH, is a tightly woven three-dimensional network composed of [Ni(Him)6]2+ cations (Him is imidazole) interlinked by the oxydiacetate anion through six different N-H⋯O bonds, in which all the N-H imidazole groups, as well as all the carboxylate O atoms, take part. This structure is the first to show an [Ni(Him)6]2+ group which does not display any crystallographic symmetry. © 1999 International Union of Crystallography

Synthesis and characterization of polynuclear complexes of molybdenum carbonyl derivatives with pyridine-2-carbaldehyde azine (pa) and ferrocenylphosphines. Crystal structure of [Mo2(CO)6(μ-dppf)(μ-pa)] (dppf = 1,1′-bis(diphenylphosphino)ferrocene)

Novel mono- and didentate ferrocenylphosphines containing complexes, [Mo2(CO)6(dfpp)2(μ-pa)] (dfpp = diferrocenylphenylphosphine) and [Mo2(CO)6(μ-dppf)(μ-pa)], have been isolated and characterized by infrared and electronic spectroscopy, and cyclic voltammetry. For the [Mo2(CO)6(μ-dppf)(μ-pa)] complex a single crystal X-ray structure analysis evidences its double bridge nature and the asymmetry of the bridging ligands due to steric constraints. In the visible region, the new compounds show strong solvatochromic bands and this effect has been evaluated by using the E*MLCT parameter. The redox behaviour of the complexes involves molybdenum and ferrocene-based oxidations and pa-based reductions. The results are compared to the previously characterized analogous complexes based on the related ligands triphenylphosphine and 1,2-bis(diphenylphosphino)ethane. © 1998 Elsevier Science Ltd. All rights reserved

Catena(hexa-aqua-cobalt(II) tetra-aqua-(μ2-1,2,4,5-benzenecarboxylato-o, o') -cobalt(II) hydrate): A new symmetry for an old polymorphic phase

The title cobalt complex (C10H38Co2O26) consists of [Co(H2O)4(C10H2O8)]2-n anionic chains, balanced by [(Co(H2O)6]2+ cations and eight solvato water molecules, some of which are disordered. The chains are formed by Co(H2O)4 "beads" threaded by fully deprotonated benzenecarboxylato anions binding in a stretched, trans fashion, and they are linked by H-bonds into a 2D structure. The cationic groups and solvato water molecules form a second kind of 2D arrays, "sanwiched" by the latter ones and linking the lot into a 3D structure through a very complex H-bonding interaction scheme. The structure presents a very conspicuous pseudo symmetry, and it appears to be a slight polymorphic modification of an already published isologue of identical formulation but with the higher symmetry properly attained, in a volume half as large. The slight differences between both structures seems to reside mainly in the (disordered) solvates, as suggested by the overlap of both models

The crystal and molecular structures of two bromo bis(N,N-dipropylthiocarbamoyl) sulfidocopper(I) complexes

The reaction of copper(I) bromide, CuBr, with the tetraalkylthiurammonosulfides R4tms (R = iPr, nPr) affords the copper(I) complexes iPr4tmsCuBr (I) (C14H28BrCuN2S2, orthorhombic, Pna21, Z = 4, a = 12.487(2), b = 12.699(2), c = 12.742(2) Å) and nPr4tmsCuBr (II) (C14H28BrCuN2S3, monoclinic, P21/n, Z = 4, a = 9.092(5), b = 23.408(11), c = 10.082(7) Å, β = 104.90(5)°), which exist in the solid as monomeric units featuring three-coordinate copper(I). The ligands are bidentate and coordination is completed by the bromine atoms. The configurations of the six-membered metal-ligand ring in (I) and (II) are more severely distorted than the previously reported structurally related complexes of ethyl series. The crystal structural studies are complemented and confirmed by IR and 1H-NMR spectroscopies, as well as room temperature, magnetic, solution conductivity, and molecular weight studies

Triaquatris(μ-oxydiacetato)europium(III)-lanthanum(III) pentahydrate

The new heterobimetallic complex [{LaEu(oda)3(H2O)3.-5H2O} n] (oda = -O2CCH2OCH2CO2 -) has been synthesized and structurally characterized. Three tridentate oda ligands are coordinated to the smaller EuIII cation, while six adjacent outer carboxylate O atoms and three metal-bound water O atoms are bonded to the larger LaIII cation. The structure consists of a three-dimensional network with the metal centers bridged by oda carboxylate groups, with Eu⋯La separations of 6.95 (1) Å