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Two new coordination polymers of cadmium-containing polynitrile ligands have been synthesized using sovothermal methods. In both poly[trans,trans,trans-bis(μ-dicyanamido-κ2 N 1:N 3)bis(2-methylbenzimidazole-κN)cadmium(II)], [Cd(C2N3)2(C8H8N2)2] n , (I), and poly[trans,trans,trans-bis(2-methylbenzimidazole-κN)bis(μ-tricyanomethanido-κ2 N:N′)cadmium(II)], [Cd(C4N3)2(C8H8N2)2] n , (II), the Cd atom lies on a centre of inversion, in space groups P21/n and P21/c, respectively. In each polymer, each anionic ligand acts as a bridge between two metal centres, forming sheets of 24-membered rings, and in each structure a single N—H...N hydrogen bond links the polymer sheets to form a three-dimensional framework structure. Comparisons are made with the structures of some related complexes.

The title metal–organic polymer, catena-poly[[(5,5′-dimethyl-2,2′-bipyridine-κ2 N,N′)iron(II)]-di-μ-azido-κ2 N 1:N 3-[(5,5′-dimethyl-2,2′-bipyridine-κ2 N,N′)iron(II)]-di-μ-azido-κ2 N 1:N 1], [Fe(N3)2(C12H12N2)] n , features alternating μ-1,1 (end-on mode of coordination) and μ-1,3 (end-to-end mode of coordination) double azide bridges, forming chains running in the [100] direction. The octahedral coordination geometry around the FeII centre is completed by a bidentate 5,5′-dimethyl-2,2′-bipyridine ligand. Two polymorphs for this compound were obtained from the crude reaction product, the first in the space group P-1 and the other in P21/c. The molecular and crystal structures are very similar for both forms, the main difference being that the eight-membered Fe(μ-1,3-N3)2Fe metallacycle formed with end-to-end azide ligands has a nearly flat conformation in the triclinic form and a chair conformation in the monoclinic form. In spite of this geometric difference, both forms have the same density, the same packing index and similar arrangements of the one-dimensional chains in the crystal. As a consequence, they also share very similar Hirshfeld surfaces and fingerprint plots. However, a density functional theory (DFT) computational study showed that the monoclinic form is more stable than the triclinic form by ca 30.5 kJ mol−1.

Topological analysis of all known dicyanamides (dca) of metal ions was carried out. Regularities observed were applied in the design of five novel compounds.

The title compound, [Cu(C9H5N4O)2(C10H9N3)2], was synthesized solvothermally. The complex exhibits a distorted octahedral coordination geometry. The CuII atom is located on an inversion centre. The distorted octahedral CuN6 coordination sphere is composed of bidentate 2,2′-dipyridylamine in the equatorial sites while the axial sites are occupied by 1,1,3,3-tetracyano-2-ethoxypropenide ligands. In the crystal, N—H...N hydrogen bonding results in chains parallel to [010].

The synthesis, characterization, crystal structure and detailed magnetic properties of a pyrazine (pyz) and azido (N3) bridged cobalt(II) compound of formula [Co(N3)2(pyz)] (1) are reported. Compound 1 shows a layered structure formed by Co(II) chains with double μ-N3(κN1,N1) bridges that are further connected by μ-(pyrazine-κN1,N4) bridges. The layers present weak van der Waals interactions between azido terminal groups. The magnetic properties show the presence of a metamagnetic behaviour in 1 with two critical fields of 200 and 400 mT at low temperatures. AC magnetic measurements show the presence of a long-range 2D ferromagnetic order at Tc ≈ 8.0-7.0 K for dc fields above 200 mT and a long-range 3D ferromagnetic order at Tc ≈ 4.5 K for dc fields above 400 mT.

The synthesis, characterization, crystal structure and detailed magnetic properties of a pyrazine (pyz) and azido (N

The title structure consists of [Ni(CN)4]2– square-planar anions separated by layers of (C10H10N3)+ cations. The crystal packing features N—H⋯N hydrogen bonds, which generate [101] chains., In the title mol­ecular salt, (C10H10N3)2[Ni(CN)4], the dihedral angle between the pyridine rings in the cation is 1.92 (13)° and the complete anion is generated by a crystallographic centre of symmetry. An intra­molecular N—H⋯N hydrogen bond occurs in the cation, which closes an S(6) ring. In the crystal, the components are linked by N—H⋯N and weak C—H⋯N hydrogen bonds, which generate chains propagating in the [101] direction. Weak aromatic π–π stacking inter­actions are also observed. A Hirshfeld surface analysis and two-dimensional fingerprint plots indicate that the most important contact types in the crystal packing are N⋯H/H⋯N, C⋯H/H⋯C and H⋯H with contributions of 37.2, 28.3 and 21.9%, respectively.

The CoII atom in the title complex is octa­hedrally coordinated within an N2O4 donor set defined by two N-atom donors of the 1,10-phenanthroline ligand, sulfate-O and three aqua-O atoms, the latter occupying an octa­hedral face. In the crystal, supra­molecular layers parallel to (110) are sustained by aqua-O—H⋯O(sulfate) hydrogen bonding., The CoII atom in the title complex, [Co(SO4)(C12H8N2)(H2O)3] (or C12H14CoN2O7S), is octa­hedrally coordinated within a cis-N2O4 donor set defined by the chelating N-donors of the 1,10-phenanthroline ligand, sulfate-O and three aqua-O atoms, the latter occupying an octa­hedral face. In the crystal, supra­molecular layers lying parallel to (110) are sustained by aqua-O—H⋯O(sulfate) hydrogen bonding. The layers stack along the c-axis direction with the closest directional inter­action between them being a weak phenanthroline-C—H⋯O(sulfate) contact. There are four significant types of contact contributing to the calculated Hirshfeld surface: at 44.5%, the major contribution comes from O—H⋯O contacts followed by H⋯H (28.6%), H⋯C/C⋯H (19.5%) and C⋯C (5.7%) contacts. The dominance of the electrostatic potential force in the mol­ecular packing is also evident in the calculated energy frameworks. The title complex is isostructural with its manganese, zinc and cadmium containing analogues and isomeric with its mer-tri­aqua analogue.

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In the title compound, [CdNi(C9H8N2)2(CN)4] n , the Cd and Ni atoms both lie on centres of inversion in space group P21/c. The Cd atom is coordinated by two bidentate quinolin-8-amine ligands and by the N atoms of two cyano ligands, while the square planar Ni atom is coordinated by the C atoms of four cyano ligands. These units form a one-dimensional coordination polymer containing an (–NC—Ni—CN—Cd–) n backbone, and the coordination polymer chains are linked into a three-dimensional array by a combination of N—H...N and C—H...N hydrogen bonds, augmented by a π–π stacking interaction.

International audience; The compound [BiCNIm]3[DyCl6] was synthesized from a nitrile-functionalized imidazolium ionic liquid [BiCNIm][Cl] and DyCl3 ⋅ 6H2O in acetonitrile using solvothermal conditions. Structural characterization reveals that the Dy3+ ions are in a quasi-regular octahedral environment, formed by six chloride anions. The magnetic study indicates that this mononuclear compound exhibits a Single Ion Magnet behaviour. This behaviour is compared to that of other mononuclear compounds containing Dy3+ ions in various octahedral environment.

The cocrystal salt tetraaquabis[trans-1,2-bis(pyridin-4-yl)ethene-κN]iron(II) bis(1,1,3,3-tetracyano-2-ethoxypropenide)–trans-1,2-bis(pyridin-4-yl)ethene (1/2), [Fe(C12H10N2)2(H2O)4](C9H5N4O)2·2C12H10N2, is a rare example of a mononuclear FeII compound with trans-1,2-bis(pyridin-4-yl)ethane (bpe) ligands. The complex cation resides on a crystallographically imposed inversion center and exhibits a tetragonally distorted octahedral coordination geometry. Both the symmetry-independent bpe ligand and the cocrystallized bpe molecule are essentially planar. The 1,1,3,3-tetracyano-2-ethoxypropenide counter-ion is nonplanar and the bond lengths are consistant with significant electron delocalization. The extended structure exhibits an extensive O—H...N hydrogen-bonding network with layers of complex cations joined by the cocrystallized bpe. Both the coordinated and the cocrystallized bpe are involved in π–π interactions. Hirshfeld and fingerprint plots reveal the important intermolecular interactions. Density functional theory was used to estimate the strengths of the hydrogen-bonding and π–π interactions, and suggest that the O—H...N hydrogen bonds enhance the strength of the π-interactions by increasing the polarization of the pyridine rings.

Polynitrile anions are known for their ability to combine with transition metals and co-ligands to form ternary systems. Here we report on the crystal structure of tris­(2–2′-bi­pyridine)­cobalt(II) bis­(1,1,3,3-tetra­cyano-2-eth­oxy­propenide)., In the title compound, [Co(C10H8N2)3](C9H5N4O)2, the tris­(2,2′-bi­pyridine)­cobalt(II) dication lies across a twofold rotation axes in the space group C2/c. The N atoms of the three bi­pyridine ligands form a distorted octa­hedron around the cobalt ion. All the N atoms of the polynitrile 1,1,3,3-tetra­cyano-2-eth­oxy­propenide anions participate in C—H⋯N hydrogen bonds ensuring crystal cohesion and forming a three-dimensional structure. The structure is further stabilized by C—H⋯π(cation) and anion⋯π(cation) inter­actions.

A new polymeric, two-dimensional compound [Fe(4,4’-bpy)(µ1,5-dca)2].0.24(4,4’-bpy).0.5(EtOH) (1), in which dca= dicyanamide and 4,4’-bpy = 4,4’-bipyridine, has been synthesized under solvothermal conditions and fully characterized by elemental analysis, FT-IR spectroscopy and X-ray single crystal diffraction. Structural analysis of compound 1 showed it is a novel two dimensional coordination polymer, constructed from repetition of 4,4’-bpy and dca as a bidentate bridging ligand. Using the co-ligand 4,4’-bpy, lead to completely different structure geometry and network, which confirms the substantial effect of co-ligand. Furthermore, magnetic properties have been performed to understand the correlation structure-properties.

Two new compounds of general formula [M(N3)2(dmbpy)] in which dmbpy = 5,5′-dimethyl-2,2′-bipyridine, and M = Mn(II) or Co(II), have been solvothermally synthesized and characterized structurally and magnetically. The structures consist of zig-zag polymeric chains with alternating bis-µ(azide-N1)2M and bis-µ(azide-N1,N3)2M units in which the cis-octahedrally based coordination geometry is completed by the N,N’-chelating ligand dmbpy. The molecular structures are basically the same for each metal. The Mn(II) compound has a slightly different packing mode compared to the Co(II) compound, resulting from their different space groups. Interestingly, relatively weak interchain interactions are present in both compounds and this originates from π–π stacking between the dmbpy rings. The magnetic properties of both compounds have been investigated down to 2 K. The measurements indicate that the manganese compound shows spin-canted antiferromagnetic ordering with a Néel temperature of TN = 3.4 K and further, a field-induced magnetic transition of metamagnetism at temperatures below the TN. This finding affords the first example of an 1D Mn(II) compound with alternating double end-on (EO) and double end-to-end (EE) azido-bridged ligands, showing the coexistence of spin canting and metamagnetism. The cobalt compound shows a weak ferromagnetism resulting from a spin-canted antiferromagnetism and long-range magnetic ordering with a critical temperature, TC = 16.2 K.

We report the synthesis, crystal structure and Hirshfeld surface analysis of Fe(II) complex based on a pentadentate N4Py (N4Py = N,N-bis(2-pyridylmethyl)-N-(bis-2-pyridylmethyl)amine) and polynitrile tcnspr (1,1,3,3-tetracyano-2-thiopropylpropenide) ligands, [Fe(N4Py)(tcnspr)](tcnspr) 1. The X-ray result, indicates that 1 is low-spin Fe(II) complex. The tcnspr coordinated molecule in the cation exhibits disorder over two sets of atomic sites having occupancies of 0.681 (6) and 0.319 (6) and the uncoordinated tcnspr anion is also disordered over two sets of atomic sites with occupancies 0.574 (7) and 0.426 (7). The crystal packing of 1 is established mainly by weak intermolecular C–H…N/S/C hydrogen bonds and stacking interactions involving the pyridine ring and/or the C–C≡N moieties. Hirshfeld surface analysis employing three-dimensional molecular surface contours and contacts enrichment ratio calculations were used to understand the intermolecular interactions present in the structure.

FS gratefully acknowledges the Algerian MESRS (Ministere de l’Enseignement Superieur et de la Recherche Scientifique), the DGRSDT (Direction Generale de la Recherche Scientifique et du Developpement Technologique), as well as the Universite Ferhat Abbas Setif 1 for financial support. In the title compound, [Fe{(C5H4N)3N}2][C{C(CN)2}3], both ions lie across centres of inversion, with the anion being statistically disordered over two sets of atomic sites having equal occupancy. The cation and anion have approximate 3 and 32 symmetry, respectively, and the Fe---N bond lengths indicate low-spin FeII. A combination of two-centre C—H···N and three-centre C—H···(N)2 hydrogen bonds link the ions into complex sheets. Several low-occupancy water molecules are present, whose H atoms could not be located: accordingly, the reflection data were subjected to the SQUEEZE procedure [Spek (2015). Acta Cryst. C71, 9-18]. Publisher PDF

In crystal structures of two chain coordination polymers [M(tcnopr3OH)2(H2O)2] (M = NiII and CoII; tcnopr3OH− = [(NC)2CC(O(CH2)3OH)C(CN)2]−) based on a N,O or N,N′-bridge polynitrile ligand, the parallel chains are connected via, respectively, CN⋯H–O and O–H⋯O hydrogen bonds between uncoordinated functional groups of the ligand and coordinated water molecules. Upon heating, both solids undergo dehydration accompanied by degradation of their single crystals. Powder X-ray diffraction showed that non-isostructural triclinic single crystals transformed to isostructural monoclinic compounds. The solid-state reaction yielded 3D coordination polymers [M(tcnopr3OH)2] (M = NiII and CoII) based on a N,N′,O-connected tcnopr3OH−. Although previously tens of complexes based on tcnopr3OH and similar anions were synthesized and X-ray characterized, none of these contain a tridentate polynitrile ligand. Thus, this study provides evidence that solid-state reactions allow obtaining novel coordination modes of polynitrile ligands. The possible pathways for the transformation of H-bonded networks to 3D coordination polymers are discussed on the basis of the topological approach. Applicability of the topological approach to predict possible networks of solid-state reaction products based on the crystal structures of initial compounds is demonstrated.

In the title compound, [Fe(C11H11N3)2](C10N6), the FeII cation is coordinated by two bis(pyridin-2-yl)methanamine (dipa) ligands and has crystallographic twofold symmetry. There are deviations from ideal octahedral geometry due to the steric requirements of the ligands. The polynitrile 1,1,3,3-tetracyano-2-(dicyanomethylidene)propane-1,3-diide (tcpd2−) dianion is disordered about an inversion center and is not coordinated to the Fe atom. The anion is not planar but has a propeller shape. In the crystal, weak N—H...N interactions between the amine H atoms of the dipa ligands and two nitrile groups of the anion form an alternating chain of cations and anions related by the C-centering of the unit cell.

The solvothermal synthesis and structural characterization of the new high-spin iron(II) complex trans,trans,trans-[bis(azido)bis(4-amino-3,5-bis(2-pyridyl)-1,2,4-triazole)iron(II)] is reported. The complex crystallizes in the triclinic space group Pī with Z = 1, a = 6.6648(3) A, b = 8.4012(3) A, c = 11.7970(5) A, α = 85.063(2)°, β = 95.063(2)°, γ = 98.5080(10)°. It is centrosymmetric with mutually trans pairs of azido, pyridyl and triazole N atoms, the Fe–N distances indicate a high-spin configuration. A combination of N H···N hydrogen bonds and π···π stacking interactions generates a sheet structure in which the shortest Fe···Fe distance is 6.6648(3) A. Hirshfeld surface analysis has been performed for visualizing, exploring and quantifying intermolecular interactions that stabilize the crystal packing of the complex. Non-covalent interactions present in the crystal structure have also been analysed by means of computational tools. The interaction energies associated with the different interaction topologies were calculated and QTAIM and NBO analyses were applied to study the origin and nature of the attractive forces.

A p-Cu 2 O/n-ZnO heterojunction was grown directly on fluorine-doped tin oxide (FTO) substrate by two-step electrodeposition in aqueous solution. The electrical characteristics of the p-Cu 2 O/FTO and n-ZnO/FTO were studied using the Mott-Schottky (M-S) analysis in the electrolyte solution. High donor and acceptor concentrations were obtained for ZnO and Cu 2 O layers, respectively. The p-Cu 2 O/n-ZnO heterojunction show long electron lifetime and high electron–hole separation efficiency according to the electrochemical impedance spectroscopy (EIS) measurements and photocurrent response. The morphological, structural, optical, and electrical characteristics of p-Cu 2 O/n-ZnO heterojunction were investigated by field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), UV–Vis and photoluminescence (PL) analysis. The FE-SEM cross-section images confirm the formation of well-defined cubic Cu 2 O grains on continuous and flat surface of ZnO layer. XRD result points to high crystallinity of (111)-oriented p-Cu 2 O layer on (101)-oriented n-ZnO layer. The optical band gap energies of n-ZnO and p-Cu 2 O thin film are 3.3 and 2.3 eV, respectively. The current–voltage (I–V) characteristics of Au/p-Cu 2 O/n-ZnO/FTO heterojunction shows well-defined rectifying behavior with turn on voltage of 0.5 V in dark and high photoresponse under illumination.

The synthesis, structure and properties of cis-diaquabis(2,2′-dipyridylamine)zinc bis(1,1,3,3-tetracyano-2-propoxy-propenide), [Zn(H2O)2(2,2′-dpa)2][tcnopr]2, I, and its isomorphous Cd analog, II, are reported. These two coordination compounds were prepared through hydrothermal reactions of Zn(II)/Cd(II) acetate with potassium 1,1,3,3-tetracyano-2-propoxy-propenide (tcnopr– = [(NC)2CC(OPr)C(CN)2]−) in the presence of 2,2′-dipyridylamine (dpa = C10H9N3) as a co-ligand. Both new compounds were fully characterized by elemental analysis, FT-IR spectroscopy, powder XRD and X-ray single-crystal diffraction. Single-crystal X-ray analysis has revealed that compounds I and II are isostructural containing octahedrally coordinated metal ions, and exhibit 3D supramolecular architectures, including multiple anion-π interactions. Furthermore, the photoluminescence properties in the solid state at room temperature and Hirshfeld surfaces analysis to understand the packing have also been investigated in detail.

The synthesis, characterization and 3D structure determination of Zinc and Cadmium compounds are reported, containing the non-chelating bidentate ligand 4,4'-bipyridine and the anions 1,1,3,3-tetracyano-2-propoxy-propenide (tcnopr) or 1,1,3,3-tetracyano-2-ethoxy-propenide (tcnoet). The structures consist of linear chains (1D) built from metal ions and 4,4'-bipyridine, where the octahedral coordination around the metals is completed by two trans anions tcnoet (or tcnopr), and two trans-oriented water molecules. Weak interchain interactions are present, based on hydrogen bonds between the water ligands (both hydrogens are involved) and two CN groups of two nearby other chains. Metal-ligand distances appear as uneventful. For the same anion, the Zn and Cd compounds are isomorphous. Possible decomposition of the compounds has been investigated in the temperature range 30-800 degrees C in a static air atmosphere. Thermal analysis studies (TG, DTG, DTA) show that the axial water ligands for all three compounds are gradually lost upon heating above 60 degrees C to about 170 degrees C. Luminescence properties, recorded as powders, are reported as well, and these appear as strong for the Cd compound I, when irradiated at 390 nm, extremely weak for the Cd compound II, when irradiated at wavelengths from 300-400 nm, and moderately weak for the Zn compound III when irradiated at 385 nm. (C) 2019 The Author(s). Published by Elsevier Ltd.

The cocrystal salt tetraaquabis[trans-1,2-bis(pyridin-4-yl)ethene-κN]iron(II) bis(1,1,3,3-tetracyano-2-ethoxypropenide)-trans-1,2-bis(pyridin-4-yl)ethene (1/2), [Fe(C