Tetragonal Pyramid Research Articles

Квантово-химическое исследование механизмов реакций бензамида и бензолсульфонамида с хлорангидридом 3-нитробензолсульфокислоты в газовой фазе

Quantum-chemical simulation of mechanisms of 3-nitrobenzenesulfonic acid chloride interactions with benzoic and benzenesulfonic acids amides in the gas phase was carried out by calculating the three-dimensional potential energy surfaces of these reactions (DFT//B3LYP/6-311G(d,p) level). It was found that in both of the processes considered, a single route can be realized containing a single saddle point and starting as an axial attack of the nucleophile. Further approach of the reagent molecules proceeds with a decrease in the angle of nucleophilic attack to ≈ 130o in the reaction transition state and ≈ 100o – in the reaction product – sulfonamide. It was shown that the studied reactions proceed according to the bimolecular concerted mechanism of nucleophilic substitution SN2, which implies the formation of a single transition state along the reaction pathway. It was found that the geometric structure of the reaction centers in the transition states of the processes is intermediate between the trigonal bipyramid and the tetragonal pyramid, which is explained by the change in the angle of nucleophilic attack when the reagent molecules approach each other. It was found that in benzamide sulfonylation reaction, a cyclic transition state is formed, in which the forming and loosening bonds lie in the same plane, and the H-Cl distance corresponds to the length of the hydrogen bond. In benzenesulfonamide reaction with 3-nitrobenzenesulfonyl chloride, the transition state is not cyclic. The activation energies of the reactions are calculated; they were 155 kJ/mol in the benzamide sulfonylation reaction and 150 kJ/mol in the process with the participation of benzenesulfonic acid amide. The closeness of the obtained values is associated with the similar structure of the amide and sulfamide groups containing electrophilic centers near the amino groups. A significant difference in the rate constants of the studied reactions, which was found earlier, when they occur in aqueous dioxane, is explained by the features of –CONH2 and –SO2NH2 groups specific solvation and the contribution of the entropy factor to the reaction rate: the cyclic transition state of the benzamide reaction with 3-nitrobenzenesulfonyl chloride is more ordered in comparison with a non-cyclic transition state of the reaction with benzenesulfonamide participation, which can promote faster occurence of the first process.

Density Functional Theory Modeling of Molecular Structures of Heteroligand 3d M(IV) Complexes with Porphyrazine and Oxo Anion

The molecular structures of (6666) macrotetracyclic (M(IV) chelates (M = Ti, V, Cr, Mn, Fe, Co, Ni, Cu) with the (NNNN)-donor ligand porphyrazine and the oxo ligand have been calculated by the DFT OPBE/TZVP method. Selected bond lengths and bond and nonbonded angles in the complexes have been reported. The standard enthalpies, entropies, and Gibbs energies of formation of these compounds have been calculated. All these complexes have a structure of a distorted tetragonal pyramid, where the complex-forming M(IV) atom is located above the base formed by the donor nitrogen atoms. It has been demonstrated that all six-membered metal chelate rings in each of these structures are identical to each other both in the sum of their bond angles and in their set, although none of them is flat. The images of the molecular structures of some of these coordination compounds are presented.

Investigation of thermal behavior of mixed-valent iron borates vonsenite and hulsite containing [OM4]n+and [OM5]n+oxocentred polyhedra byin situhigh-temperature Mössbauer spectroscopy, X-ray diffraction and thermal analysis

The investigation of elemental composition, crystal structure and thermal behavior of vonsenite and hulsite from the Titovskoe boron deposit in Russia is reported. The structures of the borates are described in terms of cation-centered and oxocentred polyhedra. There are different sequences of double chains and layers consisting of oxocentred [OM4]n+ tetrahedra and [OM5]n+ tetragonal pyramids forming a framework. Elemental composition was determined by energy-dispersive X-ray spectroscopy (EDX). Oxidation states and coordination sites of iron and tin in the oxoborates are determined using Mössbauer spectroscopy and compared with EDX and X-ray diffraction data (XRD). According to results obtained from high-temperature Mössbauer spectroscopy, the Fe2+ to Fe3+ oxidation in vonsenite and hulsite occurs at approximately 500 and 600 K, respectively. According to the high-temperature XRD data, this process is accompanied by an assumed deformation of crystal structures and subsequent solid-phase decomposition to hematite and warwickite. It is seen as a monotonic decrease of volume thermal expansion coefficients with an increase in temperature. A partial magnetic ordering in hulsite is observed for the first time with Tc ≃ 383 K. Near this temperature, an unusual change of thermal expansion coefficients is revealed. Vonsenite starts to melt at 1571 K and hulsite melts at 1504 K. Eigenvalues of thermal expansion tensor are calculated for the oxoborates as well as anisotropy of the expansion is described in comparison with their crystal structures.

One-dimensional corner-shared hybrid lead halides with broadband emission

Herein, by well-designing organic cations as templates, we reported three new one-dimensional (1D) lead halides, [(Me)4-pipz]PbCl4 (1), [(Me)4-pipz]PbBr4 (2) and [DAPr-pipz]PbCl4·H2O (3), connected by purely corner-shared tetragonal pyramid building units of PbX5 (X = Cl, Br). Remarkably, compound 3 exhibits broadband yellow-green emission with photoluminescence quantum yield (PLQY) of 1.64% excited by UV light at room temperature, which shows potential in fabrication of white-light emitting diodes. This work provides a novel structural model to understand the relationship between structure and photoluminescence.

Kainotropite, Cu4Fe3+O2(V2O7)(VO4), a new mineral with a complex vanadate anion from fumarolic exhalations of the Tolbachik volcano, Kamchatka, Russia

ABSTRACT The new mineral kainotropite Cu4Fe3+O2(V2O7)(VO4) was found in sublimates of fumaroles related to the Tolbachik volcano, Kamchatka, Russia. The holotype specimen originates from the Yadovitaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption; associated minerals are hematite, langbeinite, calciolangbeinite, tenorite, piypite, lyonsite, rutile, pseudobrookite, sanidine, and lammerite. In paleo-fumarolic deposits of Mountain 1004 kainotropite is associated with diopside and hematite. It forms prismatic crystals up to 0.2 × 0.2 × 0.5 mm3, isolated or combined in clusters up to 0.7 mm across. Kainotropite is iron-black to reddish-black, with semi-metallic luster. Dcalc is 4.10 g/cm3. In reflected light, kainotropite is grey, weakly anisotropic. The reflectance values [Rmax–Rmin,% (λ, nm)] are: 18.3–17.3 (470), 17.3–16.3 (546), 16.9–15.7 (589), 16.3–15.1 (650). The chemical composition of the holotype sample (wt.%, electron microprobe) is: CuO 46.69, Al2O3 1.40, Fe2O3 10.04, TiO2 0.32, V2O5 37.58, As2O5 2.55, MoO3 0.76, total 99.34. The empirical formula, based on 13 O apfu, is: Cu3.96Fe3+0.85Al0.19Ti0.03(V2.78As0.15Mo0.04)Σ2.97O13. Kainotropite is orthorhombic, Pnma, a = 14.139(2), b = 6.7102(7), c = 11.4177(15) Å, V = 1083.3(2) Å3, and Z = 4. The strongest reflections of the powder XRD pattern [d,Å(I)(hkl)] are: 8.89(100)(101), 5.728(33)(002), 3.698(35)(212), 3.357(52)(020,203), 3.034(77)(220), 2.968(60)(303), and 2.655(27)(321,204). The crystal structure was solved from single-crystal XRD data, R = 0.085. Kainotropite represents a novel structure type. Cu2+ polyhedra (distorted tetragonal pyramids and strongly distorted octahedra) and Fe3+ octahedra are connected via common edges to form zigzag ribbons. Adjacent ribbons are connected by both V2O7 and VO4 groups (isolated from each other) to form a heteropolyhedral pseudo-framework. The name kainotropite is derived from the Greek word καινóτρoπoς, unusual, in allusion to its uncommon (for natural vanadates) anionic composition: it is the first mineral containing both pyrovanadate (V2O7)4– and orthovanadate (VO4)3– anions.

Synthesis, structural characterization and antiproliferative potential of copper 4′-phenyl-terpyridine complexes constructed from building block reaction

Reactions between 4′-phenyl-terpyridine (L0) and Cu(II) nitrate resulted in the formation of complex [Cu(NO3)2L0](H2O) (1). Further reaction of this compound as a building block with sodium citrate, sodium benzoic and a tetra-methylpyridyl functionalized Cyclam ligand led to the compounds as [Cu(L0)2](NO3)2(H2O)1.5 (2), [Cu(ONO2)L0(OCOC6H5)](1.5H2O)(0.5CH3CN) (3) and [Cu2(NO3)2(L0)2L](NO3)2(H2O)2 (4), respectively. The four compounds were characterized by Elemental analysis, IR, UV–vis, and single crystal X-ray diffraction. Moreover, the thermal stability of 1 and 4 were determined by TG-DTA. In 1, 3 and 4, Cu ion is coordinated with one terpyridine motif and two oxygen atoms or one oxygen and one nitrogen atoms from two auxiliary ligands, resulting in a distorted CuN3O2 or CuN4O tetragonal pyramid geometry, while 2 is a sandwich structure, forming a regular-octahedron CuN6 coordination structure. The functionalized cyclam ligand L shows only one conformation with two pendant pyridyl groups coordinating to two copper ions and the other two being free in a para-mode conformation. The separation between the two copper ions in one molecule is 14.9398 (9) Å. Three human cancer cell lines were used for antiproliferative potential: human lung cancer cell line (A549), human colon cancer cell line (HCT-8) and human breast cancer cell line (MCF-7). The results have shown that these copper compounds have good inhibitory effects on cancer cells, which are better than that of the commonly used clinical drug cisplatin.

A New Energetic Complex: Synthesis, Structure, and Combustion Catalysis Performance

The potential of tetrazole-based ligands for forming energetic complexes applied in pyrotechnics and propellants is demonstrated with the use of 5,5’-(1,3-phenylene)bis(1H-tetrazole) (H2BTB) to generate an energetic complex with high energy. A new energetic complex of PbII-tetrazolate, [Pb2(BTB)2(H2O)8]·5H2O (1), was synthesized and structurally characterized by single crystal X-ray diffraction. Structural analysis reveals that the central PbII ions present two distinct coordination environments in the asymmetric unit, including distorted pentagonal bipyramid and distorted tetragonal pyramid geometries, respectively. To identify potential combustion catalyst as additives in propellants, we employed differential scanning calorimetry technique to evaluate the influence of the complex on thermal decomposition of ammonium perchlorate (AP) and cyclotrimethylenetrinitramine (RDX). The kinetic parameters of an exothermic process for the catalytic system of RDX+1 were investigated by the Kissinger’s and Ozawa-Doyle’s methods. For both AP and RDX, the decomposition temperature decreased obviously in the presence of 1, and the released heat could effectively compensate the propellants. Our observations demonstrate that 1 shows good catalytic activity toward the thermal decomposition of AP and RDX.

Unprecedented Dinuclear CuII N,O-Donor Complex: Synthesis, Structural Characterization, Fluorescence Property, and Hirshfeld Analysis

An unprecedented dinuclear CuII complex, [Cu2(L2)2], derived from a salamo-like chelating ligand H2L2, was produced by the cleavage of a newly synthesized, half-salamo-like ligand HL1 (2-[O-(1-ethyloxyamide)]oxime-3,5-dichloro-phenol). This was synthesized and characterized by elemental analyses, IR, UV–Vis and fluorescent spectra, single crystal X-ray diffraction analysis, and Hirshfeld surface analysis. X-ray crystallographic analysis indicated that the two CuII (Cu1 and Cu2) ions bore different (N2O3 and N2O2) coordination environments, the penta-coordinated Cu1 ion possessed a slightly twisted tetragonal pyramid geometry with the τ value τ = 0.004, and the tetra-coordinated Cu2 ion showed a slightly twisted square planar geometry. Interestingly, one oxime oxygen atom participated in the coordination reported previously. Moreover, an infinite two-dimensional layered supramolecular network was formed. Compared with HL1, the CuII complex possessed the characteristic of fluorescence quenching.

Heterospin Cobalt, Nickel, and Copper Complexes: 4-TEMPO-oxy-3,6-di-tert-butyl-o-Benzoquinone Derivatives

A series of heterospin bis-o-semiquinone cobalt, nickel, and copper complexes (4-TEMPO-oxy-3,6-di-tert-butyl-o-benzoquinone derivatives) is synthesized: (DMSO)Cu(4-TEMPO-O-3,6-DBSQ)2 (I), (THF)2Ni(4-TEMPO-O-3,6-DBSQ)2 (II), (Py)2Ni(4-TEMPO-O-3,6-DBSQ)2 (III), and (Py)2Ni(4-TEMPO-O-3,6-DBSQ)2 (IV) (4-TEMPO-O-3,6-DBQ is 4-(3,6-di-tert-butyl-1,2-dioxocyclohexa-3,5-dien-4-yloxy)-2,2,6,6-tetramethylpiperidine-1-oxyl 4-oxy-2,2',6,6'-tetramethylpiperidine-1-oxyl). All complexes are characterized by elemental analysis, IR spectroscopy, magnetochemistry, and EPR. The structure of complex I is determined by X-ray diffraction analysis (CIF file CCDC no. 1882878). The coordination polyhedron of the copper atom in the molecular structure of the Cu(II) bis-o-semiquinone complex with dimethyl sulfoxide (DMSO) is a distorted tetragonal pyramid, whose equatorial plane contains the o-semiquinone ligands, and the DMSO molecule occupies the apical position. The magnetic properties of complexes I–IV are consistent with their compositions and structures. The magnetic behavior of copper complex I and nickel complexes II and III is determined by the balance of two contributions: metal–ligand ferromagnetic exchange interaction and ligand–ligand antiferromagnetic interaction. The temperature dependence of the magnetic moment of cobalt complex IV shows the redox isomeric transformation conjugated with the spin transition, which is characteristic of complexes of this type. No participation of nitroxyl radical centers is observed in intermolecular coordination.

Two organic–inorganic hybrid Schiff base copper materials: synthesis and their catalytic properties for constructing C–N bonds

Two Schiff base copper complexes: [Cu(H2O)2(HL1)]·2H2O (1) (H3L1 =2-((2,4-dihydroxybenzylidene)amino)acetic acid) and [Cu(L2) (CH3OH)]4 (2) (H2L2 = 3-phenyl-2-(2-hydroxy-5-chlorobenzylideneamino)propane-1-ol), have been simply synthesized and fully characterized. Single crystal X-ray diffraction (SXRD) revealed that 1 consists of one five-coordinated copper atom and one deprotonated Schiff base ligand HL1. The copper atom in 1 showed the distorted tetragonal pyramid geometry, whereas, four copper atoms in 2 were six-coordinated and exhibited the distorted octahedron geometry. Importantly, two Schiff base complexes were further used as catalysts in Chan–Lam coupling reaction and 2 demonstrated excellent catalytic performance in construction of C–N bonds (yields up to 87%).

A Temperatural Semi-Memorized Phase Transition in a 1D Organic-Inorganic Hybrid Material of Sb|||-Based [(CH2)3NH2S]2SbCl5.

The hybrid organic-inorganic materials have received extraordinary attention from the academic community not only because of their natural chemical tunability but also because of their potential in producing exotic physical properties. However, these characteristics are usually caused by the phase transition of materials under changing of external terms, and it is crucial to fully understand their origins. Here, we research an unusual phase transition near room temperature between two ordered phases in a one-dimensional (1D) hybrid organic-inorganic material of Sb|||-based [(CH2)3NH2S]2SbCl5 (1). This phase transition is caused by collective actions, including the primary variation in the bonds of inorganic five-coordinated tetragonal pyramids, displacement and rotation of organic and inorganic components, along with concurrent hydrogen bonds transformation. Afterward, we observe a significant dielectric anomaly at low frequencies between low and high temperatures. This attributed to the fact that two phases coexist with the lessening temperature, which means that a small number of high-temperature features remained but did not occur during the heating process. These findings offer an avenue for inventing a fresh phase transition and dielectric switch hybrid materials, which further open up the prospect for their practical application.

Syntheses, luminescences and Hirshfeld surfaces analyses of structurally characterized homo-trinuclear ZnII and hetero-pentanuclear ZnII-LnIII (Ln = Eu, Nd) bis(salamo)-like complexes

Homo-trinuclear [Zn3(L)(μ2-OAc)2(H2O)].CH2Cl2 (1) and hetero-pentanuclear [Zn4(L)2Eu(NO3)3(H2O)] (2) and [Zn4(L)2Nd(NO3)3(H2O)]·CH3CH2OH (3) complexes containing a coumarin-skeleton bis(salamo) ligand H4L, were successfully prepared and characterized via the means of elemental analyses, single crystal X-ray crystallography, FT-IR, UV–Vis absorption spectroscopy and Hirshfeld surfaces analyses. Complex 1 is a 1:3 ((L)4−:ZnII) structure, and complexes 2 and 3 are 2:4:1 ((L)4−:ZnII:LnIII) structure. All ZnII atoms in complexes 1–3 occupied the N2O2 sites are five-coordinated with geometries of slightly distorted tetragonal pyramid and trigonal bipyramid. Rare earth metal (EuIII and NdIII) atoms are both coordinated with phenolic oxygen atoms, and eight-coordinated with the square antiprism geometries in complexes 2 and 3. Water molecules as coordinating solvents participate in the coordination. Supra-molecular structures are built by CH…π and hydrogen bonding interactions in complexes 1–3. Moreover, Hirshfeld surfaces analyses of complexes 1–3 were also analysed in detail. Most important of all, luminescences of complexes 1–3 were discussed.

Wolfgang Schnick

Wolfgang Schnick

Octasodium bis-(Nitrilo-tris-Methylenephosphanatooxovanadate(IV))-Dioxo-bis-Oxovanadium(IV) Icosohydrate Na8[(VO)2(μ−O)2{(VO)μ3−N(CH2PO3)3}2]·20H2O

Crystal hydrate of sodium salt of an oxovanadium(IV) complex with nitrilo-tris-methylenephosphonic (NTP) acid Na8[(VO)2(μ−O)2{(VO)μ3−N(CH2PO3)3}2]·20H2O is synthesized, isolated, and studied: space group P1, Z = 2, a = 12.5829(2) A, b = 13.9297(2) A, c = 15.1051(3) A, α = 72.233(2)°, β = 76.907(2)°, γ = 70.388(2)°. The NTP ions are completely deprotonated and hexadentate. In coordinating the VO2+ ion each NTP ion closes three N–V–O–P–C cycles with a common N–V bond. By means of bridging vanadyl ions and oxo ligands the four-membered V–O–V–O cycle and the [–V–O–P–O–]4 macrocycle are closed. Coordination V polyhedra are distorted tetragonal pyramids. With regard to the occurrence of weak V–N bonds the polyhedra of two V atoms can be completed to strongly distorted octahedra.

Redefinition of Lemanskiite: New Mineralogical Data, Crystal Structure, and Revised Formula NaCaCu5(AsO4)4Cl · 3H2O

The crystal structure of lemanskiite is determined for the first time (R = 0.019) and the mineral is redefined. Its chemical formula, crystal system, space group and unit-cell parameters are revised. The powder X-ray diffraction pattern of lemanskiite has been correctly indexed; the IR spectrum of an impurity-free sample has been obtained. It has been shown that the mineral is not a dimorph of lavendulan NaCaCu5(AsO4)4Cl · 5H2O and differs from the latter by a lower H2O content. The studied sample was from the oxidation zone of the Perseverancia deposit, Guanako, Antofagasta, Chile. It empirical formula is Na0.98(Ca0.98Sr0.03)Σ1.01Cu5.07As3.97O15.97Cl1.03 · 3H2O; the idealized formula is NaCaCu5(AsO4)4Cl · 3H2O. The mineral is monoclinic, P21/m, a = 9.250(2), b = 10.0058(10), с = 10.0412(17) A, β = 97.37(3)°, V = 921.7(3) A3, Z =2. Lemanskiite represents a new structure type in the lavendulan group. Its structure is based on heteropolyhedral layers composed of clusters consisting of four edge-shared distorted Cu-centered tetragonal pyramids joined with eight AsO4 tetrahedra, which are also linked with a Cu-centered plane squares not involved in the clusters. Interlayer edge-shared Na-centered trigonal prisms and Ca sevenfold polyhedra are linked with the heteropolyhedral layers from both sides.

Co(III), V(IV) and Cu(II) complexes of bidentate N,O‐donor Schiff base ligands: Characterization, anticancer activities and metal oxide nanoparticles preparation via solid state thermal decomposition

Three new mononuclear Schiff base complexes [Co(L1)3 (1), VO(L1)2 (2) and Cu(L2)2 (3)] were synthesized, characterized and used as a precursor for preparation of metal oxide nanoparticles. The crystal structure of compounds was determined using single crystal X‐ray diffraction. The Co(III) coordination sphere consists of three phenolato oxygens and three imino nitrogen atoms from three Schiff base ligands, thus forming a distorted octahedral geometry. In complex (2), the vanadium(IV) is five‐coordinated in a regular tetragonal pyramid fashion and the Cu(II) ion is four coordinated with a square‐planar geometry in the complex (3). The nanoparticles were characterized by Fourier transform infrared spectroscopy (FT‐IR), X‐ray powder diffraction (XRD) and field emission scanning electron microscopy (FE‐SEM). In vitro cell proliferation via MTT assay was studied to calculate the cytotoxicity of complexes and metal oxide nanoparticles against gastric cancer cell line (MKN‐45). The results showed that all compounds have anticancer activity with dose–response dependency.

Complexes of An(VI) with Cyclobutanecarboxylic Acid Anions and Outer-Sphere Alkali Metal Cations

New complexes of hexavalent actinides with cyclobutanecarboxylic acid (Hcbc) anions, Na4[NpO2· (cbc)3]4·H2O (I), K[NpO2(cbc)3] (II), Cs[NpO2(cbc)3] (III), and Cs[PuO2(cbc)3] (IV), cbc = C4H7(COO)–, were synthesized and studied by single crystal X-ray diffraction. The structures of I–IV are based on the anionic complexes [AnO2(cbc)3]– surrounded by alkali metal cations. The AnO 2 2+ cation in the anionic complex is bonded with three chelating C4H7COO– anions, and the coordination polyhedron (CP) of An is a hexagonal bipyramid with the O atoms of the AnO 2 2+ cations in apical positions. The coordination number (CN) of the alkali metal cations in the structures of II–IV is the same and equal to 6; the coordination surrounding of the K+ and Cs+ cations is constituted by the O atoms of six C4H7COO– anions. The crystal structures of II–IV are examples of cubic 3-connected networks (10,3) built of alkali metal and actinide cations. In the structure of I, there are four kinds of crystallographically different NpO 2 2+ and Na+ cations. The coordination surrounding of the NpO 2 2+ cations differs only in the conformational characteristics of the C4H7COO– ligands. Four independent Na+ cations differ from each other in the structure of the coordination surrounding. The CPs of the Na(1) and Na(4) atoms can be described as distorted octahedra (CN 6); that of Na(3), as a trigonal prism (CN 6); and that of Na(2), as a tetragonal pyramid (CN 5) with one of the basal vertices occupied by the Ow(1) atom of a water molecule. In the structure of I, the configuration of the network formed by the Na and Np cations differs from the cubic 3-connected network found in the structures of II–IV.

Structural Insight into Redox Dynamics of Copper Bound N-Truncated Amyloid-β Peptides from in Situ X-ray Absorption Spectroscopy.

X-ray absorption spectroscopy of CuII amyloid-β peptide (Aβ) under in situ electrochemical control (XAS-EC) has allowed elucidation of the redox properties of CuII bound to truncated peptide forms. The Cu binding environment is significantly different for the Aβ1-16 and the N-truncated Aβ4-9, Aβ4-12, and Aβ4-16 (Aβ4-9/12/16) peptides, where the N-truncated sequence (F4R5H6) provides the high-affinity amino-terminal copper nickel (ATCUN) binding motif. Low temperature (ca. 10 K) XAS measurements show the adoption of identical CuII ATCUN-type binding sites (CuIIATCUN) by the first three amino acids (FRH) and a longer-range interaction modeled as an oxygen donor ligand, most likely water, to give a tetragonal pyramid geometry in the Aβ4-9/12/16 peptides not previously reported. Both XAS-EC and EPR measurements show that CuII:Aβ4-16 can be reduced at mildly reducing potentials, similar to that of CuII:Aβ1-16. Reduction of peptides lacking the H13H14 residues, CuII:Aβ4-9/12, require far more forcing conditions, with metallic copper the only metal-based reduction product. The observations suggest that reduction of CuIIATCUN species at mild potentials is possible, although the rate of reduction is significantly enhanced by involvement of H13H14. XAS-EC analysis reveals that, following reduction, the peptide acts as a terdentate ligand to CuI (H13, H14 together with the linking amide oxygen atom). Modeling of the EXAFS is most consistent with coordination of an additional water oxygen atom to give a quasi-tetrahedral geometry. XAS-EC analysis of oxidized CuII:Aβ4-12/16 gives structural parameters consistent with crystallographic data for a five-coordinate CuIII complex and the CuIIATCUN complex. The structural results suggest that CuII and the oxidation product are both accommodated in an ATCUN-like binding site.

Coordination‐directed and Hydrogen‐bonded Assembly of Supramolecular Architectures Constructed from Diverse Coordination of Linear, Triangular, Tetragonal Pyramid, Trigonal Bipyramid, and Octahedral Mononuclear Units

Reaction of a imidazole phenol ligand 4‐(imidazlo‐1‐yl)phenol (L) with 3d metal salts afforded four complexes, namely, [Ni(L)6]·(NO3)2 (1), [Cu(L)4(H2O)]·(NO3)2·(H2O)5 (2), [Zn(L)4(H2O)]·(NO3)2·(H2O) (3), and [Ag2(L)4]·SO4 (4). All complexes are composed of monomeric units with diverse coordination arrangements and corresponding anions. All the hydroxyl groups of monomeric cations are used as hydrogen‐bond donors to form O–H···O hydrogen bonds. However, the coordination habit of different metal ions produces various supramolecular structures. The NiII atom shows octahedral arrangement in 1, featuring a 3D twofold inclined interpenetrated network through O–H···O hydrogen bond and π–π stacking interaction. The CuII atom of 2 displays square pyramidal environment. The O–H···O hydrogen bond from the [Cu(L)4(H2O)]2+ cation and lattice water molecule as well as π–π stacking produce one‐dimensional open channels. NO3– ions and lattice water molecules are located in the channels. 3 is a 3D supramolecular network, in which ZnII has a trigonal bipyramid arrangement. Two different rings intertwined with each other are observed. The AgI in 4 has linear and triangular coordination arrangements. The mononuclear units are assembled into a 1D chain by hydrogen bonding interaction from coordination units and SO42– anions.

Low-dimensional compounds containing cyanido groups. Part XXXIV. Structure, spectral and magnetic properties of the first complex with pyridylbenzimidazole and nonlinear pseudohalide anion

Abstract From the system CuCl2 – pbi – NaN(CN)2 −, polymeric [CuCl(μ1,5-dca)(pbi)]n·nH2O (1) complex (dca=dicyanamide, pbi=2-(2-pyridyl)benzimidazole) was isolated and characterized by structure analysis, spectral and magnetic measurements. Infrared spectroscopy confirmed the presence of pbi, dca and water molecules in 1. Its solid-state structure is formed by infinite chains running along the b axis. In the chain, the Cu(II) atom is penta-coordinated by two nitrogen atoms of chelate pbi ligand, by two nitrile nitrogen atoms of bridging μ1,5-dca and by chloride ligand which occupies the apical position of tetragonal pyramid around the Cu(II) atom. Asymmetric unit is supplemented by one molecule of solvated water, which along with chlorine atom serves as acceptors in intermolecular hydrogen bonds and along with π–π interactions create a 3D supramolecular structure. Magnetic measurements revealed the presence of a weak ferromagnetic exchange interaction J/kB =0.11 K.