trans-Dichloridotetrakis­[1-(2-hydroxy­ethyl)-1H-tetrazole-κN 4]cobalt(II)

The title cobalt(II) complex, [CoCl2(C3H6N4O)4], was obtained from metallic cobalt by direct synthesis. There are two Co atoms in the asymmetric unit, each lying on an inversion centre and adopting a distorted octa­hedral coordination. Classical and non-classical hydrogen bonds are responsible for formation of a three-dimensional polymeric network in the crystal

catena-Poly[cobalt(II)-di-μ-chlorido-κ4 Cl:Cl-μ-1,5-dimethyl-1H-tetra­zole-κ2 N 3:N 4]: an X-ray powder investigation

The asymmetric unit of the title compound, [CoCl2(C3H6N4)]n, contains two Co atoms, both lying on inversion centres, two Cl atoms and one 1,5-dimethyl­tetra­zole ligand. The coordination polyhedra of both Co atoms adopt flattened octa­hedral geometry, with two N atoms from two ligands in axial positions and four Cl atoms in equatorial sites. Neighbouring Co atoms are linked together via two bridging Cl atoms and one tetra­zole ring to form polymeric chains running along the a axis

catena-Poly[[bis­[1-(2-hydroxy­ethyl)-1H-tetra­zole-κN 4]copper(II)]-di-μ-chlorido]: a powder study

The crystal structure of the title polymeric complex, [CuCl2(C3H6N4O)2]n, was obtained by the Rietveld refinement from laboratory X-ray powder diffraction data collected at room temperature. The unique CuII ion lies on an inversion center and is in a slightly distorted octa­hedral coordination environment. In the hydroxy­ethyl group, all H atoms, the O atom and its attached C atom are disordered over two positions; the site occupancy factors are ca 0.6 and 0.4. The OH group is involved in an intra­molecular O—H⋯N hydrogen bond

The effect of climate change on avian offspring production: A global meta-analysis

Climate change affects timing of reproduction in many bird species, but few studies have investigated its influence on annual reproductive output. Here, we assess changes in the annual production of young by female breeders in 201 populations of 104 bird species (N = 745,962 clutches) covering all continents between 1970 and 2019. Overall, average offspring production has declined in recent decades, but considerable differences were found among species and populations. A total of 56.7% of populations showed a declining trend in offspring production (significant in 17.4%), whereas 43.3% exhibited an increase (significant in 10.4%). The results show that climatic changes affect offspring production through compounded effects on ecological and life history traits of species. Migratory and larger-bodied species experienced reduced offspring production with increasing temperatures during the chick-rearing period, whereas smaller-bodied, sedentary species tended to produce more offspring. Likewise, multi-brooded species showed increased breeding success with increasing temperatures, whereas rising temperatures were unrelated to repro- ductive success in single-brooded species. Our study suggests that rapid declines in size of bird populations reported by many studies from different parts of the world are driven only to a small degree by changes in the production of young

The First Characterized Coordination Compounds of Macrocyclic Ligands Including Incorporated Tetrazole Rings

The macrocyclic binuclear tetrazole, 2,2,5,5-tetramethyl-12-oxa-1,6,7,8,16,17,18,19-octaazatricyclo­[13.2.1.16,9]­nonadeca-7,9(19),15(18),16-tetraene (<b>L</b>), reacts with copper­(II) chloride or copper­(II) tetrafluoroborate hexahydrate to give complexes [Cu₃Cl₆L₂] (<b>1</b>) or [CuL₂(H₂O)₂]­(BF₄)₂(H₂O) (<b>2</b>), respectively. According to single crystal X-ray analysis, both complexes were found to be coordination polymers. In the crystal structure of complex <b>1</b>, there are neutral linear bibridged trinuclear units Cu₃Cl₆, in which the copper atoms are linked together by double chlorine bridges. Neighboring Cu₃Cl₆ units are bonded to each other by two bridging macrocyclic ligands L due to coordination bonds Cu–N between terminal copper atoms of Cu₃Cl₆ units and the tetrazole ring nitrogen atoms of ligands L to form polymeric chains. In complex <b>2</b>, the copper atom is bonded to three ligands L via the tetrazole ring nitrogen atoms, and to two water molecules, with formation of a square-pyramidal coordination of the metal. In this complex, one of two independent ligands L shows monodentate coordination, whereas another ligand plays the role of a bridge between two neighboring copper atoms being responsible for formation of polymeric cationic chains [CuL₂(H₂O)₂]_<i>n</i>^2<i>n</i>+. A complex system of hydrogen bonds connects the chains and the anions BF₄^– into a three-dimensional network. The temperature-dependent magnetic susceptibility measurements of complex <b>1</b> revealed that the copper­(II) ions were ferromagnetically coupled showing a coupling constant <i>J</i> of 50 cm^–1