Coordinated Ethanol Molecules Research Articles

Crystal structure of the sodium salt of mesotrione: a triketone herbicide

The crystal structure of the sodium salt of mesotrione, namely, catena-poly[[sodium-μ3-2-[(4-methanesulfonyl-2-nitrophenyl)carbonyl]-3-oxocyclohex-1-en-1-olato] ethanol monosolvate], {[Na(C14H12NO7S)]C2H5OH} n , is described. The X-ray structural analysis results reveal that the coordination sphere is established by two chelating O atoms, the O atom of the coordinated ethanol molecule, and an O atom from the methylsulfonyl group of a neighboring molecule. Simultaneously, an O atom of the cyclohexane fragment serves as a bridge to a neighboring sodium ion, forming a flat Na–O–Na–O quadrangle, thereby forming a mono-periodic polymer. The structure displays O—H...O hydrogen bonds and C—H...O short contacts. Thermogravimetric analysis (TGA) data indicate that the sodium salt of mesotrione decomposes in four stages.

Crystal structure and Hirshfeld surface analysis of bis-(μ-4-tert-but-oxy-4-oxobut-2-en-2-olato)bis-[(4-tert-but-oxy-4-oxobut-2-en-2-olato)ethano-lzinc(II)

The mol-ecular and crystal structure of the title binuclear Zn2+ complex, [Zn2(C8H13O3)4(C2H5OH)2], with enolated anionic tert-butyl-aceto-acetate and ethanol was analysed. The coordination polyhedra of the Zn atoms are distorted octa-hedra formed by six oxygen atoms that belong to three ligand mol-ecules and a coordinated ethanol mol-ecule. In the crystal phase, alternating layers can be distinguished parallel to the ac plane. A Hirshfeld surface analysis showed that there are no strong inter-molecular inter-actions in the structure. The most significant contributions to the overall crystal packing are from H⋯H inter-molecular contacts.

Investigations of stable penta- and hexa-coordinate polynuclear Zn(II) and Cd(II) complexes derived from a single-armed salamo-based ligand

A penta-coordinated dinuclear Zn(II) complex, [Zn2(L)(μ-PhCOO)(EtOH)] (1), and a hexa-coordinate tetranuclear Cd(II) complex, [{Cd2(L)(EtOH)(η-OAc)}2]·2CH2Cl2 (2), have been synthesized by reactions of a single-armed salamo-based ligand, H3L, and two kinds of transition metal salts, (Zn(NO3)2·6H2O and Cd(OAc)2·2H2O), respectively. Complexes 1 and 2 have been characterized by elemental analyses, single crystal X-ray diffraction, IR spectra and UV-Vis spectra. Complex 1 is composed of a totally deprotonated ligand (L)3- moiety, two Zn(II) ions, one μ-PhCOO- counter-anion and one coordinated ethanol molecule. The (L)3- unit packages two Zn(II) ions, the μ-PhCOO- counter-anion bridges two adjacent Zn(II) ions and one ethanol molecule coordinates with the Zn2 ion, so that both Zn(II) ions are penta-coordinated with slightly distorted trigonal bipyramidal configurations, and the τ5 values of Zn1 and Zn2 are 0.86 and 0.65, respectively. Complex 2 consists of two discrete and similar electroneutral tetra-nuclear units, 2 A and 2B, and two crystallized dichloromethane molecules. Each unit has a symmetric structure that is made up of two completely deprotonated ligand (L)3- moieties, four Cd(II) ions, two η-OAc- counter-anions and two coordinated ethanol molecules. Fluorescence properties and Hirshfeld surfaces analyses have been studied as well.

Investigation of two novel di- and tetra-nuclear Cu(II) bis(salamo)-type complexes

Two kind of structurally different bis(salamo)-type polynuclear Cu(II) complexes, including [Cu2(HL)(EtOH)Cl2]·CH2Cl2 (1), [Cu4(L)2(EtOH)2](NO3)2·2EtOH (2) have been prepared by the reactions of the ligand H3L with CuCl2·2H2O and Cu(NO3)2·3H2O, respectively. The crystal structures of complexes 1 and 2 were characterized by X-ray crystallographic examination. Complex 1 crystallizes in triclinic system, P−1 space group, forming a unique homo-dinuclear Cu(II) complex consisting of two Cu(II) ions, one inadequately deprotonated ligand (HL)2− unit, and one ethanol molecule. The fundamental structure of complex 2 with centrosymmetric double-helical structure is two totally deprotonated ligand (L)3− units, two central Cu(II) atoms, and two coordinated ethanol molecules, which crystallizes in monoclinic system, P 21/c space group. Complexes 1 and 2 constructed by the bis(salamo)-type ligand are built into three-dimensional and two-dimensional frameworks by intermolecular interactions. Hirshfeld surfaces studies were used to quantify the various interactions of complexs 1 and 2. The spectral properties of complexes 1 and 2 were studied by ultraviolet and infrared spectroscopy. Moreover, fluorescence characteristics are carried out. Undoubtedly, these studies can enrich the structural diversity of bis(salamo)-type Cu(II) complexes.

Exploring two helical centrosymmetric homotetranuclear Cu (II) bis (salamo)‐based complexes

AbstractTwo helical centrosymmetric homotetranuclear Cu (II) complexes, [Cu4(L)2(EtOH)2](ClO4)2·2EtOH·2CHCl3(1)and [{Cu4(L)2(EtOH)2}{Cu4(L)2(HNO3)2}](NO3)4·3EtOH·3MeOH(2), were synthesized by the reactions of a symmetric bis (salamo)‐based ligand H3L with Cu(ClO)2·6H2O and Cu(NO)3·3H2O, respectively, and certified by elemental analyses, UV–Visible absorption spectra, infrared spectra and single‐crystal X‐ray analysis techniques. X‐ray crystal structure analyses reveal that four Cu (II) atoms of complex1are attached to two deprotonated ligand (L)3−units with the help of two coordinated ethanol molecules, and then forming a helical centrosymmetric complex by H‐bonding and π⋯π interactions. While complex2unit cell contains two crystallographically independent but chemically identical homotetranuclear complexes (moleculesAandB), eight Cu (II) atoms are coordinated by four deprotonated ligand (L)3−units. The coordination mode of four Cu (II) atoms from moleculeAis the same as complex1; at the same time, oxygen atoms on nitrates are involved in the coordination of another four Cu (II) atoms from moleculeB. The short‐range interactions in complexes1and2were calculated by Hirshfeld surfaces analyses. The molecular orbital energy levels, molecular stabilities of complexes1and2were analyzed by DFT calculations. In addition, antibacterial assays were also investigated in detail.

Self-assembling of three rare structurally various homomultinuclear CuII complexes derived from a bis(salamo)-based multioxime ligand

A family of rare structurally different homometal multinuclear CuII bis(salamo)-based complexes, [Cu4(L)2(MeOH)2](ClO4)2·2MeOH (1), [Cu4(L)2(EtOH)2](NO3)2·2EtOH (2) and [Cu2(HL)(EtOH)Br2]·CHCl3 (3), has been successfully synthesized by the reactions of cupric salts with a bis(salamo)-based multidentate chelate ligand (H3 L). The salamo-based ligand [R-CH=N—O—(CH2) n —O—N=CH—R] is a new type of salen-based analog. Complexes (1) and (2) are isostructural structures, and crystallize in monoclinic space group P21/n with centrosymmetric spiral structures, where the main structures contain two fully deprotonated ligand (L)3− units, a charged tetranuclear CuII folding center and two coordinated solvent molecules. Complex (3) crystallizes in monoclinic space group Cc and consists of two CuII cations, one incompletely deprotonated ligand (HL)2− unit and one coordinated ethanol molecule, and forms a novel homo-binuclear CuII complex structure due to Br− counter anions. Complexes (1)–(3) have zero-dimensional cluster-based structures and are further assembled into three-dimensional frameworks via intermolecular interactions. Because of the different solvents and counter anions which have a significant influence on the structures of complexes (1)–(3), the interactions were quantitatively evaluated by Hirshfeld surfaces analyses. Complexes (1)–(3) have been characterized by elemental analyses, IR spectra, UV–vis spectra and X-ray crystallography analyses. In addition, fluorescence properties are evaluated and DFT calculations are performed.

Bis(ethanol-κO)bis(1-ferrocenyl-4,4,4-trifluorobutane-1,3-dionato-κ2 O,O′)nickel(II)

In the title compound, [NiFe2(C5H5)(C9H5F3O2)2(C2H6O)2], the central NiII ion is observed in an octa-hedral coordination environment. The chelating β-diketonate ligands are substituted by ferrocene, a lipophilic organometallic moiety. The ferrocene groups have the normal geometry, with eclipsed cyclo-penta-diene rings. Coordinated ethanol mol-ecules are engaged in inter-molecular hydrogen bonds, and the crystal is further stabilized by weak C-H⋯F and C-H⋯π contacts.

Exploring a more flexible N2O2-donor ligand and its octahedral tri-nuclear Co(II) and Ni(II) complexes

Two new tri-nuclear Co(II) and Ni(II) complexes, [{Co(L)(μ-OAc)(EtOH)}2Co]·2EtOH·2CH2Cl2 (1) and [{Ni(L)(μ-PhCOO)(MeOH)}2Ni]·2CH3OH·4H2O (2), were synthesized by complexing H2L (4-methylcoumarin-2,2′-[(propane-1,3-diyldioxy)bis(nitrilomethylidyne)]diphenol) with Co(OAc)2⋅4H2O and Ni(NO3)2·6H2O, respectively, and characterized by chemical-physical characterization. For 1, the crystallographic analysis revealed there are three Co(II) ions, two completely deprotonated ligands (L2–), two coordinated ethanol molecules and two bidentate bridging acetate groups (μ-OAc-). Complex 2 is composed of three Ni(II) ions, two completely deprotonated L2– ligands, two coordinated methanol molecules and two bidentate bridging benzoate groups (μ-PhCOO–). The fluorescence properties of 1 and 2 were studied. The supramolecular structures of 1 and 2 are formed by intermolecular hydrogen bonds or π-related interactions. The important intermolecular interactions of H2L and 1 and 2 were quantitatively determined by Hirshfeld surfaces analyses. In order to determine the kinetic stabilities of H2L, 1 and 2, DFT calculations were performed at B3LYP/SDD level of theory.

Insight into two unusual stable homomultinuclear copper (II)‐based bis (salamo)‐type complexes

AbstractUsing symmetrical bis (salamo)‐type tetraoxime ligand H3L and Cu (ClO4)2·6H2O in different solvent systems, two unusual homomultinuclear Cu (II) complexes, [Cu4(L)2(CH3CH2OH)2](ClO4)2·2H2O (1) and [Cu2(L)]n (ClO4)n·nCH3CN (2), were synthesized and characterized by single‐crystal X‐ray diffraction analyses, elemental analyses, infrared (IR), ultraviolet–visible (UV–Vis) spectroscopy, Hirshfeld surfaces analyses, and density functional theory (DFT) calculations. Complex 1 includes [Cu4(L)2(CH3CH2OH)2]2+ ion, two ClO4− counter anions, two coordinated ethanol molecules and two aquatic dissociative molecules, the two deprotonated ligand (L)3− units package around four Cu (II) ions yield a centrosymmetric helical molecules with a charged linear folding center, while complex 2 forms a 1‐D linear topology structure and is only the substitution of chloroform in the solvent system of complex 1 with acetonitrile. Coordination mode of complex 2 is widely different from that of complex 1. In the Cu (II) ions of complex 1, there are two coordination modes of Cu (II) ions, the hexa‐coordinated distorted octahedral structure and the penta‐coordinated distorted tetragonal pyramid structure, but complex 2 only has almost perfect tetragonal pyramid geometry. Fluorescence properties of H3L and its complexes 1 and 2 have also been explored.

Molecular and supramolecular structures of self-assembled Cu(II) and Co(II) complexes with 4,4’-[6-(3,5-dimethyl-1H-pyrazol-1-yl)-1,3,5-triazine-2,4-diyl]dimorpholine ligand

The molecular and supramolecular structures of [Cu(PTM)Cl2]∗0.75MeOH (1), [Co(PTM)Cl2]; (2A) and [Co(PTM)Cl2(EtOH)]; (2B) complexes, where PTM is 4,4’-[6-(3,5-dimethyl-1H-pyrazol-1-yl)-1,3,5-triazine-2,4-diyl]dimorpholine, were presented. In complexes 1 and 2A, the Cu(II) and Co(II) are tetra-coordinated with a distorted tetrahedral coordination environment. In case of complex 2B, an additional ethanol molecule is found coordinated with Co(II) leading to a highly distorted penta-coordinated Co(II) complex. In all cases, the PTM ligand is acting as a bidentate NN-chelate. Hirshfeld surface analysis indicated the importance of H⋯H (49.0–55.1%), Cl⋯H (18.8–20.5%) and O⋯H (8.3–9.9%) contacts in the molecular packing. The electron transferences from the ligand units to the central metal atom as well as the spin density distribution were discussed based on DFT calculations. The presence of coordinated ethanol molecule in 2B weakened the Co-N and Co-Cl interactions compared to 2A. Using atoms in molecules topology analysis, the coordinate bonds between metal (Co or Cu) and donor atoms (N, O, Cl) belong to closed shell interactions with weak covalent characters.

Syntheses, Characterization and X-ray Crystal Structure of Polymeric Heteronuclear Oxo-bridged Fe/Na Assembled with Salen-type Schiff Base and Dicyanamide

Reaction of FeCl₂.4H₂O with 2-(-(2-(-2-hydroxy-3-methoxybenzylideneamino)phenylimino)methyl)-6-methoxyphenol (H₂L) gives the metalloligand [Fe(L)].(H₂O) (1). Reaction of metalloligand (1) with three fold of sodium dicyanamide Na[N(CN)₂] gives the new tetranuclear compound [{Fe<SUP>II</SUP>Na<SUP>I</SUP>(L)(EtOH)(HN(CN)₂)}(<i>μ</i>-O){Fe<SUP>III</SUP>Na<SUP>I</SUP>(L)(NO₃)]}]_n (2) in which one of the two irons is oxidized to +3. Suitable crystals of (2) were grown by slow evaporation of ethanol solution during two weeks. The metalloligand (1) and the tetranuclear (2) complexes are characterized by IR and physical measurement. Spectroscopic evidence indicated that the Schiff base H₂L behave an N₂O₂O’₂ coordination tetradentate ligand. The structure of (2) was elucidated by X-ray diffraction analysis. The asymmetric unit of the compound contains two dideprotonated ligand molecules, two iron ions, one hexacoordinated sodium ion, one heptacoordinated sodium ion, one bidentate nitrate group, one monodentate dicyanamide unit, one coordinated ethanol molecule and an O^2- ion which acts as a bridge between the Fe<SUP>II</SUP> and the Fe<SUP>III</SUP> of two entities: [Fe<SUP>II</SUP>Na<SUP>I</SUP>(L)(EtOH)(HN(CN)₂)] and [Fe<SUP>III</SUP>Na<SUP>I</SUP>(L)(NO₃)]. Bridge Fe—O(<i>μ</i>) bond lengths are 1.7813(14) and 1.7856(13) Å and bridging angle Fe—O—Fe is 144.78(8)°. The second terminal cyano group of the dicyanamide link another molecule complex through the heptacoordinated Na<SUP>I</SUP> leading a polymeric structure. Intermolecular hydrogen bond connect the polymeric chains to develop a three dimensional structure.

Syntheses, Characterization, and X-ray Crystal Structure of Heteronuclear Zn/Na Assembled with Salen-type Schiff Base

Herein we reported the crystal structure of a dinuclear complex [{Zn^IINa^I (L)(EtOH)(NO₃)]}] (2) obtained by reaction with the metalloligand [Zn(L)].(H₂O) (1) and sodium nitrate. The metalloligand (1) and the dinuclear (2) complexes are characterized by IR and physical measurement. Spectroscopic evidence indicated that the Schiff base H₂L behave an N₂O₂O’ ₂ coordination tetradentate ligand. Suitable crystals of the compound 2 were grown by slow evaporation of ethanol solution for two weeks. The structure of 2 was elucidated by X-ray diffraction analysis. The compound crystallizes in the monoclinic crystal system with a space group of <i>P2_1/c</i>. The asymmetric unit of the compound contains one dideprotonated ligand molecule, on tetracoordinated zinc (II) ion, one heptacoordinated sodium(I) ion, one bidentate nitrate group and one coordinated ethanol molecule resulting in a structure formulated as [Zn(<i>µ</i>-<i>L</i>)Na(NO₃)(EtOH)]. In the structure the Zn^II ion is tetracoordinated and the environment around the zinc (II) is best described as a planar square geometry. The Na^I ion is seven-coordinated in a severely distorted bipyramid pentagon environment. The interplanar angles between the two phenyl rings with a methoxy substituent is 4.208 (4)°, while the dihedral angle values of these groups with the phenyl carrying amino groups are respectively 7.499 (5)° and 11.594 (5)°. The Zn–Na distance is 3.4244 (9) Å. In the crystal structure numerous intramolecular and intermolecular hydrogen bonds link the molecules in a three-dimensional network.

БУДОВА КОМПЛЕКСУ ЦИНКУ З ЦИКЛОГЕКСИЛАЦЕТОАЦЕТАТОМ

Binuclear complex of Zn(II) with cyclohexyl acetoacetate was obtained and structurally characterized for the first time. According to structural data, the crystal system is triclinic, space group P-1; a = 7.6530(4), b = 12.2412(8), c = 12.9102(9) Å; α = 90.198(5), β = 101.071(5), γ = 96.937(5) deg. The molecular structure corresponds to the formula [Zn2(C10H15O3)4(C2H5OH)2]. The complex is located in a special position to the symmetry center of the unit cell. The coordination polyhedrons of the Zn atoms are the same distorted octahedrons formed by six oxygen atoms. Each formed by 4 oxygen atoms in the equatorial position, which belong to three ligand molecules: terminal ligand (2 oxygen atoms) and bridged ligand (1 oxygen atom) which chelate the zinc atom of the named polyhedron and 1 oxygen atom belong to a bridged ligand that chelates the other nucleus and monodentantly coordinated to mentioned one. Two oxygen atoms occupy an axial position, one of which belongs to the terminal ligand, mentioned above and the other to the coordinated ethanol molecule. The bond between the complex nuclei is stabilized by two hydrogen bonds formed by the hydrogen atoms from hydroxyl groups of ethanol molecules and the enol oxygen atoms of the terminal ligands of the other nucleus. The compound was also characterized by IR-spectroscopy, characteristic bands (сm-1) are: ν(C–H) - 2936, 2860, ν(C=O) &amp; ν(C=C) – 1612, ν(C=O) + δ(C–H) – 1532, ν(C=C) &amp; ν(C-CH3)– 1252, δ(C–H) – 1172, π(C–H) – 784, ν(M–O) – 456, 416. IR spectroscopy data confirm the bidentate coordination of cyclohexyl acetoacetate to zinc atoms in deprotonated form with the formation of chelated metallocycles. The structure of the complex is similar to the structures of cobalt and nickel complexes with cyclohexyl acetoacetate. Analysis of XRD-data (which are supplemented with this work) for Co(II), Ni(II) and Zn(II) complexes with acetoacetic acid esters shows that their structure, in particular the number of metal centers in the structures, regardless of the nature of the central atom or the alcohol fragment, but determined the presence of components capable of complementing the coordination sphere of the metal in reaction media.

End-to-End Azido-Bridged Lanthanide Chain Complexes (Dy, Er, Gd, and Y) with a Pentadentate Schiff-Base [N3O2] Ligand: Synthesis, Structure, and Magnetism.

The syntheses, structure and magnetic properties are reported for five novel 1D polymeric azido-bridged lanthanide complexes with the general formula {[Ln(DAPMBH)(N3)C2H5OH]C2H5OH}n where H2DAPMBH = 2,6-diacetylpyridine bis(4-methoxybenzoylhydrazone)-a new pentadentate pyridine-base [N3O2] ligand and Ln = Dy (1), Y0.930Dy0.070 (2), Er (3), Y0.923Er0.077 (4), and Gd (5). X-ray diffraction analysis of 1-5 show that the central lanthanide atoms are eight-coordinated with the N5O3 donor set originating from the ligand DAPMBH, one coordinated ethanol molecule and two end-to-end type N3- bridges connecting the metal centers into infinite chain. The [LnN5O3] coordination polyhedron can be regarded as a distorted dodecahedron (D2d). AC magnetic measurements revealed that compounds 1-4 show field-induced single-molecule magnet behavior, with estimated energy barriers Ueff ≈ 47-17 K. The experimental study of magnetic properties was complemented by theoretical analysis based on crystal-field calculations. Direct current magnetic susceptibility studies revealed marginally weak intrachain exchange interaction between Ln3+ ions mediated by the end-to-end azide bridging groups (J ≈ -0.015 cm-1 for 5). Comparative analysis of static and dynamic magnetic properties of magnetically concentrated (1, 3) and diluted (2, 4) Dy and Er compounds showed that, despite fascinating 1D azido-bridged chain structure, compounds 1 and 3 are not single-chain magnets; their magnetic behavior is largely due to single-ion magnetic anisotropy of individual Ln3+ ions.

Solvent-driven structures and slow magnetic relaxation behaviors of dinuclear dysprosium clusters

Three dinuclear dysprosium compounds, [Dy2(dbm)2(L)2(H2O)2]·CH3CN (1), [Dy2(dbm)3(L)(HL)(CH3OH)]·CH3OH (2) and [Dy2(dbm)2(L)2(C2H5OH)2] (3) (H2L = N′-(2-hydroxybenzylidene)-2-(hydroxyimino)-propanohydrazide, Hdbm = 1,3-diphenyl-1,3-propanedione), were successfully synthesized by controlling the reaction solvents. Single-crystal X-ray diffraction analysis reveal that 1–3 all possess [Dy2O2] core, whereas their coordination solvents are different with two coordinated water molecules for 1, one coordinated methanol molecule for 2 and two coordinated ethanol molecules for 3. All the eight-coordinated Dy(III) ions of 1–3 are located in a distorted bicapped trigonal-prismatic (BCTP) geometry. Interestingly, magnetic investigation reveal that compounds 1–3 exhibit distinct slow magnetic relaxation behaviors with the energy barrier (2.29 ± 1.17) K for 1, (1.31 ± 1.05) K for 2 and (45.61 ± 3.24) K for 3. This work provides a promising strategy for the construction and regulation of lanthanide single-molecule magnetisms.

Synthesis and Fluorescence Properties of a New Heterotrinuclear Co(II)-Ce(III)Complex Constructed from a bis(salamo)-Type Tetraoxime Ligand.

[Co2(L)Ce(OAc)3(CH3CH2OH)]·1.5CH3OH∙0.5CH2Cl2, a heterotrinuclear Co(II)-Ce(III) bis(salamo)-type complex with a symmetric bi(salamo)-type ligand H4L and an acyclic naphthalenediol moiety, was designed, synthesized and characterized by elemental analyses, FT-IR, UV-Vis and fluorescence spectroscopy and X-ray crystallography. The X-ray crystallographic investigation revealed the heterotrinuclear complex consisted of two Co(II) atoms, one Ce(III) atom, one (L)4‒ unit, three μ2-acetate ions, one coordinated ethanol molecule, one and half crystallization methanol molecule and half crystallization dichloromethane molecule. Two Co(II) atoms located in the N2O2 coordination spheres, are both hexacoordinated, with slightly distorted octahedral geometries. The Ce(III) atom is nine-coordinated and located in the O6 cavity possesses a single square antiprismatic geometry. In addition, supramolecular interactions exist in the Co(II)-Ce(III) complex. Two infinite 2D supramolecular structures are built via intermolecular O–H···O, C–H···O and C–H···π interactions, respectively.

Selective CO2 adsorption by a new metal-organic framework: synergy between open metal sites and a charged imidazolinium backbone.

Metal-organic frameworks (MOFs) are porous, tunable crystalline materials that are attracting widespread scientific attention for their potential use in post-combustion CO2 capture. In this work, we report the synthesis of a new ligand, 1,3-bis(4-carboxyphenyl)-4,5-dihydro-1H-imidazol-3-ium tetrafluoroborate, H2Sp5-BF4, that is subsequently used for the construction of a novel MOF, Cu-Sp5-EtOH. This highly crystalline material has a charged framework that is expected to give rise to high CO2/N2 selectivity. However, the pores of the parent structure could not be accessed due to the presence of strongly coordinated ethanol molecules. After solvent exchange with methanol and subsequently heating Cu-Sp5-MeOH under vacuum, we are able to liberate the solvent providing other small molecules like CO2 access to the inside of the now porous structure, Cu-Sp5. The combination of open metal sites and framework charge leads to an exceptionally high CO2/N2 selectivity, as determined by Ideal Adsorbed Solution Theory (IAST) calculations performed on single-component adsorption isotherms. The CO2/N2 selectivity of Cu-Sp5 reaches a value of over 200 at pressures typically found in post-combustion flue gas (0.15 bar CO2/0.85 bar N2), a value that is among the highest reported to date.

Three Polymorphic Forms of a Monomeric Mo(VI) Complex: Building Blocks for Two Metal–Organic Supramolecular Isomers. Intermolecular Interactions and Ligand Substituent Effects

Three polymorphic forms of the molybdenum(VI) complex [MoO2(L)(EtOH)] (1α, 1β, and 1γ) (L2– = 4-methoxy-2-oxybenzaldehyde isonicotinylhydrazonate) were synthesized by the reaction of H2L with the dioxobis(acetylacetonato)molybdenum(VI) complex, [MoO2(acac)2], in ethanol. Removal of the coordinated ethanol molecule upon grinding or heating led to the solid-state transformation of the polymorphs 1α, 1β, or 1γ into the coordination polymer [MoO2(L)]n (2a). The square inclusion complex [MoO2(L)]4⊃CH2Cl2·4CH2Cl2 (2b⊃CH2Cl2·4CH2Cl2) was obtained by a self-assembly reaction in dichloromethane. Standard Gibbs energies of binding for molybdenum(VI) compounds [MoO2(L)(D)] with the sixth coordination site occupied by a nitrogen or an oxygen donor D were estimated using quantum chemical calculations. Crystal and molecular structures of the molybdenum(VI) compounds [MoO2(L)(EtOH)] (1α, 1β, and 1γ), [MoO2(L)]4⊃CH2Cl2·4CH2Cl2 (2b⊃CH2Cl2·4CH2Cl2), [MoO2(L)(γ-pic)]·γ-pic (3·γ-pic), [MoO2(L)(py)] (4), and [MoO2(L)(DMSO)] (5) were determined by the single crystal X-ray diffraction method. The compounds were further characterized by chemical analysis, thermogravimetric, and differential scanning calorimetry measurements, IR, UV–vis, one- and two-dimensional NMR spectroscopies, and the powder X-ray diffraction method.

Synthesis, Crystal Structure, and Catecholase Activity of Three Trinuclear Heterometallic NiII2–MnII Complexes Derived from a Salen‐Type Schiff Base Ligand

AbstractThree new trinuclear heterometallic nickel(II)–manganese(II) complexes, [(NiL)2Mn(NCS)2] (1), [(NiL)2Mn(NCO)2] (2), and [{NiL(EtOH)}2Mn(NO2)2]·2EtOH (3), have been synthesized by using [NiL] as the so‐called “ligand complex” [where H2L = N,N′‐bis(salicylidene)‐1,3‐propanediamine] and have been structurally characterized. Crystal structure analyses revealed that complexes 1 and 2 are angular trinuclear species, in which two terminal four‐coordinate square planar [NiL] moieties are coordinated to a central MnII through double phenoxido bridges. The MnII is in a six‐coordinate distorted octahedral environment that is bonded additionally to two mutually cis nitrogen atoms of terminal thiocyanate (in 1) and cyanate (in 2). In complex 3, in addition to the double phenoxo bridge, the two terminal NiII ions are linked to the central MnII by means of a nitrite bridge (1κN:2κO) that, together with a coordinated ethanol molecule, gives rise to an octahedral environment around the NiII ions and consequently the structure becomes linear. Catecholase activity of these three complexes was examined by using 3,5‐di‐tert‐butylcatechol (3,5‐DTBC) as the substrate. All three complexes mimic catecholase activity and the rate of catechol oxidation follows saturation kinetics with respect to the substrate and first‐order kinetics with respect to the catalyst. The EPR spectra of the complexes exhibit characteristic six line spectra, which indicate the presence of high‐spin octahedral MnII species in solution state. The ESI‐MS positive spectrum of 1 in the presence of 3,5‐DTBC has been recorded to investigate possible complex–substrate intermediates.

Anions make the difference: conversion from zero- to one-dimensional structures and luminescent properties of lanthanide-based complexes

Reaction of a newly designed amide type ligand, benzyl-N,N-bis[(2′-benzylaminofomyl)phenoxyl)ethyl]-amine (L) with lanthanide nitrates and picrates has produced two isostructural series of lanthanide coordination compounds, [Ln2L2(NO3)6(DMF)2]n [series 1, monoclinic P21/c, Ln = Pr (1), Sm (2), Eu (3), Tb (4), and Dy (5)] and [LnL(pic)3(CH3CH2OH)]n [series 2, triclinic P, Ln = Nd (6), Eu (7), Tb (8), and Er (9)]. Series 1 have zero-dimensional (0D) dinuclear rectangular macrocycle architectures, while series 2 exhibit one-dimensional (1D) chain patterns. Meanwhile, the two series of structures are further connected through weak intermolecular hydrogen bonds to yield three-dimensional (3D) supramolecular structures. The variations from zero- to one-dimensional coordination structures are attributed to different steric confinement of the nitrate and picrate anions. In addition, we have studied the luminescent properties of the nitrate and picrate complexes, and found that the picrate complexes give very weak luminescence due to coordinated ethanol molecules existing in complexes, which decrease the luminescence. So, herein the luminescent properties of only the Sm (2), Eu (3), Tb (4), and Dy (5) nitrate complexes are investigated in detail.