Self-penetrating and interpenetrating 3D metal-organic frameworks constructed from 4-(4-carboxyphenoxy)-phthalic acid and <Emphasis Type="Italic">N</Emphasis>-donor auxiliary ligands

Two new interesting entangled structures, namely, [Ni_1.5(L)(bpy)₂(H₂O)₃] _n · 3nH₂O (I) and [Cd₃(L)₂(bbi)₂]n · nH₂O (II)(where H₃L is 4-(4-carboxyphenoxy)-phthalic acid, bpy is 4,4′-bipyridine, and bbi is 1,1′-(1,4-butanediyl)bis(imidazole)) have been synthesized and characterized by elemental analysis (EA), infrared spectra (IR), X-ray powder diffraction (XRPD), solid fluorescence and thermogravimetric analysis (TGA). Single-crystal X-ray diffraction analysis revealed that complex I possesses a 3D self-penetrating framework constructed from ladder-like and fishbone-like subunits. Complex II shows a 3D framework of two-fold interpenetration assembled from trinuclear Cd(II) clusters bridged by bbi and L^3? ligands.     

Nickel(II), cobalt(II), copper(II), and zinc(II) complexes with 4′-(4‴-benzo-15-crown-5)methyloxy-2,2′:6′,2″-terpyridine: Syntheses and vibrational spectra

Complexes of 4′-(4′″-benzo-15-crown-5)methyloxy-2,2′:6′,2″-terpyridine (L) with metal perchlorates and hexafluorophosphates, [ML₂](ClO₄)₂ · nH₂O and [ML₂](PF₆)₂ · nH₂O · mC₂H₅OH (M = Ni(II), Co(II), Zn(II), Cu(II); n = 0–3; m = 0–2), were synthesized. Their vibrational spectra were studied. The spectral criteria for ligand coordination through the terpyridinic nitrogen atoms were established. The conformational structure of the B15C5 macrocycles of a ligand molecule in the synthesized complexes was proposed. The complexes were studied by thermogravimetry.     

Syntheses,crystal structures,and properties of three two-dimensional complexes constructed by flexible (2,3-pyridylmethyl)amine

Three two-dimensional coordination polymers [Cd(2,3-Pyma)Cl₂] _n (I), {[Cd(2,3-Pyma)(1,4-Chdc)] · 4H₂O}n (II) and {[Zn₂(2,3-Pyma)(1,2,4,5-Bttc)(H₂O)₄] · 6H₂O} _n (III) (2,3-Pyma = (2,3-pyridylmethyl) amine, H₂-1,4-Chdc = 1,4-cyclohexanedicarboxylic acid, and H₄-1,2,4,5-Bttc = 1,2,4,5-benzenetetracarboxylic acid) have been synthesized and structurally characterized by single crystal X-ray crystallography (CIF files CCDC nos. 989461 (I), 1055685 (II) and 1055686 (III)). Three complexes are all twodimensional layer networks bridged by the flexible 2,3-Pyma ligands or the carboxylate ligands. It is noted that the flexible 1,4-Chdc ligands bind the Cd²⁺ ions into a helical chain structure in complex II. The photoluminescence and thermal properties are investigated.     

Hydrogen bonded С–H···Y (Y = O,S, Hal) molecular complexes: A natural bond orbital analysis

Hydrogen bonded C–H···Y complexes formed by H₂O, H₂S molecules, hydrogen halides, and halogen-ions with methane, halogen substituted methane as well as with the C₂H₂ and NCH molecules were studied at the MP2/aug-cc-pVDZ level. The structure of NBOs corresponding to lone pair of acceptor Y, n_Y, and vacant anti-σ-bond C–H of proton donor was analyzed and estimates of second order perturbation energy Е⁽²⁾ characterizing donor–acceptor n_Y → σ_C-H^* charge-transfer interaction were obtained. Computational results for complexes of methane and its halogen substituted derivatives show that for each set of analogous structures, the Е_nY→σ*C-H⁽²⁾ energy tends to grow with an increase in the s-component percentage in the lone pair NBO of acceptor Y. Calculations for different C···Y distances show that the equilibrium geometries of complexes lie in the region where the E⁽²⁾ energy is highest and it changes symbatically with the length of the covalent С–H bond when the R(C···Y) distance is varied. The performed analysis allows us to divide the hydrogen bonded complexes into two groups, depending on the pattern of overlapping for NBOs of the hydrogen bridge.     

Structures and enhanced third-order nonlinear optical performance of four complexes investigated by thin film <Emphasis Type="Italic">Z-</Emphasis>scan technique

Four transition metal complexes have been synthesized via hydrothermal reactions, namely, [Zn(1,3-BIB)(CH₃COO)₂]₂ 1, [Cu₂(1,4-BIB)₃(CO₃)₂](1,4-BIB)·10H₂O 2, {[Mn(H₂O)₂(1,2-BIB)₂]Cl₂}_n 3, and {[Mn(1,2-BIB)(1,4-NDC)]₂}_n 4, where 1,n-BIB = 1,n-bis(imidazol-l-yl-methyl)benzene, n = 2, 3, 4 and 1,4-NDC = naphthalene-1,4-dicarboxylic acid. Complex 1 presents a discrete ring-like structure. Complex 2 shows a ladder-like chain structure, while complex 3 has a joint-like chain structure. Complex 4 features a layer structure constructed from [Mn₂(N₄O₈)] clusters. The third-order nonlinear optical (NLO) properties of these complexes in thin films have been investigated by employing the Z-scan technique. Complexes 1–3 exhibit strong third-order NLO reverse-saturable absorption, while 4 shows third-order NLO saturable absorption and a strong self-defocusing effect. The third-order NLO susceptibilities χ ⁽³⁾ of the four complexes were calculated as 2.74 × 10^?9, 12.24 × 10^?9, 42.78 × 10^?9 and 189.32 × 10^?9 esu, respectively. The electronic structures of the complexes were investigated by density functional theory, and the origins of their NLO properties are discussed.     

Synthesis,structure, and antibacterial properties of ternary rare-earth complexes with <Emphasis Type="Italic">o</Emphasis>-methylbenzoic Acid and 1,10-phenanthroline

Ternary rare-earth complexes with o-methylbenzoic acid (o-MBA) and 1,10-phenanthroline (Phen) Ln₂(o-MBA)₆(Phen)₂ · nH₂O(n = 0, 1) (Ln = La, Pr, Y, Yb) were synthesized and characterized by elemental analysis, IR, X-ray diffraction, and TG-DTG means. The complex La₂(o-MBA)₆(Phen)₂ · H₂O (I) is composed of two species of binuclear molecules in which the La³⁺ ion is coordinated with two nitrogen atoms of Phen and seven oxygen atoms of carboxylate groups. The carboxylate groups were bonded to La³⁺ in three modes: chelating-bidentate, bridging-bidentate, and chelating-bridging tridentate. The La³⁺ ion adopted a vigorous distorted monocapped square antiprism geometry. Complex I belongs to the triclinic crystal system, P space group, lattice parameters: a = 13.058(3), b = 12.7584(11), c = 20.773(4) Å, α = 101.18(3)°, β = 93.88(3)°, γ = 115.82(3)°, V = 3283.0(11)ų, Z = 2, ρ_calcd = 1.484 mg/m³, M _r = 1467.06, F(000) = 1476, μ = 1.350 mm^-1. The structure was refined to R _l = 0.0631 and wR ₂ = 0.1504. The antibacterial activity test indicates that these complexes exhibit better antibacterial ability against Escherichia coli and Staphylococcus aureus than the corresponding rare-earth chloride or o-MBA.     

Phase composition,formation parameters,and morphology of precipitates in the LiVO<Subscript>4</Subscript>-VOSO<Subscript>4</Subscript>-H<Subscript>2</Subscript>O system

The phase and chemical compositions of the precipitates formed in the LiVO₃-VOSO₄-H₂O system at initial pH within 1 ≤ pH ≤ 4 and 90°C were studied. The following phases were prepared: an α phase Li_1.4(VO)_1.3[H₂V₁₀O₂₈] · nH₂O and a β phase Li_{0.6 ? x} H_{1.4 + x} [V₁₂O_{31 ? y/2}] · nH₂O (0 ≤ x ≤ 0.5, 1.3 ≤ y ≤ 2.0) with a layered structure. Li_0.4V₂O₅ · H₂O nanorods with the interlayer distance 10.30 ± 0.08 Å were synthesized at 180°C in an autoclave. The morphology, IR spectra, and main formation processes for these polyvanadates were studied.     

Crystal structure of oxonium <Emphasis Type="Italic">trans</Emphasis>(O)-<Emphasis Type="Italic">cis</Emphasis>-(C)-dicyanobis(2-picolinato)cobaltate(III) hydrate: Two types of proton site

The trans(O)-cis(C)-bis(pyridine-2-carboxylato)dicyanocobaltate(III) ions, [Co(Pic)₂(CN)₂]^?, crystallize from acid medium with three water molecules per two crystallographically nonequivalent complexes whose charge is compensated by protons. One of the water molecules forms an oxonium ion (H₃O⁺) with a proton. The other two water molecules bound to each other through a short hydrogen bond O-H…O (2.403(2) Å) and thus forming (H₅O₂)⁺ cations is another proton site. The (H₃O)(H₅O₂)[Co(Pic)₂(CN)₂]₂ crystals are monoclinic: a = 10.7027(7) Å, b = 25.786(1) Å, c = 11.4865(8) Å, β = 91.411(9)°, Z = 4, space group P2₁/n.     

Synthesis,characterization, and crystal structures of 2D cobalt(II) and nickel(II) coordination polymers containing flexible bis(benzimidazole) ligands

Three coordination polymers, namely {[Ni(L1)(nip)(H₂O)]·2H₂O} _n (1), [Co(L2)(tbip)] _n (2), and {[Co₂(L3)₂(bptc)]·3H₂O} _n (3) (L1 = 1,4-bis(5,6-dimethylbenzimidazole)butane, L2 = 1,4-bis(5,6-dimethylbenzimidazole)-2-butylene, L3 = 1,3-bis(5,6-dimethylbenzimidazole)propane, H₂nip = 5-nitro-isophthalic acid, H₂tbip = 5-tert-butyl-isophthalic acid, H₄bptc = biphenyl-3,3′,4,4′-tetracarboxylic acid), have been synthesized under hydrothermal conditions and characterized by physicochemical and spectroscopic methods as well as by single-crystal X-ray diffraction analysis. Complexes 1 and 2 both feature a two-dimensional (4,4) layer with (4⁴ × 6²) topology. Complex 3 possesses a uninodal 4-connected 2D htb network. The fluorescence spectra and catalytic properties of the complexes for the degradation of methyl orange by sodium persulfate in a Fenton-like process are reported.     

Three 2D mixed-ligand Co(II) coordination polymers containing flexible bis(benzimidazole) ligands with different spacers

Three new Co(II) coordination polymers, [Co(L1)(bpdc)] _n (1), [Co(L2)(ndc)(H₂O)·2H₂O] _n (2) and [Co(L3)(ndc)(H₂O)·H₂O] _n (3) (L1 = 1,2-bis(5,6-dimethylbenzimidazole)ethane, L2 = 1,3-bis(5,6-dimethylbenzimidazole)propane, L3 = 1,4-bis(5,6-dimethylbenzimidazole)butane, H₂bpdc = 4,4′-biphenyldicarboxylic acid, H₂ndc = 2,6-naphthalenedicarboxylic acid) have been synthesized under hydrothermal conditions and structurally characterized by X-ray crystallography. All three complexes feature (4,4) networks that extend into 3D supramolecular frameworks via hydrogen bonding interactions. The luminescence properties and catalytic activities of these complexes with respect to the degradation of methyl orange in a Fenton-like process have been investigated.     

Bis(citrato)germanates of bivalent 3<Emphasis Type="Italic">d</Emphasis> metals (Fe,Co, Ni,Cu, Zn): Crystal and molecular structure of [Fe(H<Subscript>2</Subscript>O)<Subscript>6</Subscript>][Ge(HCit)<Subscript>2</Subscript>] · 4H<Subscript>2</Subscript>O

In continuation of a systematic study of bis(citrate)germanates, we synthesized a number of heterometallic germanium(IV) and 3d metal complexes based in citric acid (H₄Cit) with the molecular formula [M(H₂O)₆][Ge(HCit)₂] · nH₂O, where M = Fe, n = 4 (I); Co, n = 2 (II); Ni, n = 2 (III); Cu, n = 1 (IV); Zn, n = 3 (V). The complexes were characterized by elemental analysis, X-ray diffraction, thermogravimetry, and IR spectroscopy. The X-ray diffraction analysis of compound I was performed. Crystals are monoclinic, a = 10.091(4) Å, b = 11.126(4) Å, c = 10.996(4) Å, β = 100.966(6)°, V = 1212.1(8) ų, Z = 4, space group P2₁/n, R1 = 0.0561 for 2266 reflections with I > 2σ(I). Compound I is composed of centrosymmetric octahedral complexes-[Ge(HCit)₂]^2? anions and [Fe(H₂O)₆]²⁺ cations—and crystallization water molecules. Structural units in compound I are combined by a hydrogen bond system.     

Crystal Structure of <Emphasis Type="Italic">DL</Emphasis>-Valinium Tetrafluoroantimonate(III) Monohydrate

The crystal structure of an antimony(III) fluoride complex of the composition (C₅H₁₂NO₂)SbF₄·H₂O (I) involving a cation of α-amino isovaleric acid (DL-valine, Val) is determined. Crystals are monoclinic: a = 12.2024(2) Å, b = 6.1636(1) Å, c = 15.5167(3) Å, Z = 4, space group P2₁/c. The structure is formed of DL-valinium (C₅H₁₂NO₂)⁺ cations, complex [SbF₄]_n^n? anions having a polymeric chain structure, and crystallization water molecules. The [SbF₄]_n^n? complex anions consist of trigonal SbF4E bipyramids joined together by asymmetric bridging Sb–F(3)···Sb bonds. The structural units are organized into a threedimensional framework via N–H···F, N–H···O, and O–H···F hydrogen bonds.     

Structural characterization of a mixed-ligand complex of copper(II) with 1,10-phenanthroline and the <Emphasis Type="Italic">m</Emphasis>-aminobenzoate ion

A new copper(II) complex of 1,10-phenanthroline (C1₂H₈N₂) and the meta-aminobenzoate ion (m-amb; C₇H₆NO ₂ ^? ), having the formula Cu(C₁₂H₈N₂)(C₇H₆NO₂)Cl?0.5H₂O, is prepared and characterized by elemental analysis, IR spectroscopy, and single crystal X-ray diffraction. The structure is built up from monomeric units in which the coordination environment around the metal ion is a square plane arising from a bidentate 1,10-phenanthroline molecule, a monodentate m-amb anion, and a chloride ion. A very long (Cu–N = 2.856(5) Å) bond to the nitrogen atom of an adjacent m-amb ion generates [101] polymeric chains in the crystal. The crystal structure is consolidated by N–H???O and O–H???O hydrogen bonds and C–H???O, C–H???Cl, and aromatic π–π stacking interactions. Crystal data: C₁₉H₁₅ClCuN₃O_2.5, M _r = 424.33, monoclinic, P2₁/n (No. 14), a = 9.8200(5) Å, b = 10.9291(7) Å, c = 16.3803(9) Å, β = 105.293(3)°, V = 1695.74(17) ų, Z = 4, R(F) = 0.043, wR(F ²) = 0.122.     

Synthesis,crystal structures,luminescence, and photocatalytic properties of two 1D Co(II) coordination polymers constructed with semirigid bis(benzimidazole) and dicarboxylate ligands

Two ternary cobalt(II) coordination polymers (CPs), namely [Co(L1)(npht)] _n (1) and {[Co₂(L2)₂(npht)₂(H₂O)]·H₂O} _n (2) (L1 = 4,4′-bis(benzimidazol-1-ylmethyl)biphenyl, L2 = 1,2-bis(5,6-dimethylbenzimidazol-1-ylmethyl)benzene, and H₂npht = 4-nitrophthalic acid) have been synthesized and structurally characterized by X-ray crystallography. Both CPs feature similar 1D infinite chains containing two distinct loops. CP 1 further forms a 3D supramolecular network via weak C–H···O hydrogen bond interactions. CP 2 shows a 1D two-layer chain structure, assembled through π–π stacking interactions. The electrochemical, luminescence, and photocatalytic activities of the two CPs for the removal of methylene blue under visible or UV light were investigated. Possible photocatalytic mechanisms are discussed.     

Two novel dinuclear iron(III) complexes containing <Emphasis Type="Italic">μ</Emphasis>-oxo-di-<Emphasis Type="Italic">μ</Emphasis>-carboxylato motif

Two novel μ-oxo-di-μ-carboxylato-bridged iron(III) complexes of [Fe₂(bpea)₂(PhCO₂)₂(μ-O)] (ClO₄)₂·C₂H₅OH (1) and [Fe₂(bpma)₂(ClCH₂COO)₂(μ-O)](ClO₄)₂· H₂O (2) (bpea = N,N-bis(2-pyridylmethyl)ethylamine, bpma = N,N-bis(2-pyridylmethyl)methylamine), have been synthesized and determined by X-ray diffraction. Complex (1) crystallizes in the Orthorhombic space group P _nma with d(Fe···Fe) of 3.094 Å and average d(Fe–Ob_bridge) of 1.805 Å; Complex (2) crystallizes in the Monoclinic space group C ₂/c, with d(Fe···Fe) of 3.109 Å and average d(Fe–Ob_bridge) of 1.794 Å. The magnetic studies indicate a stronger antiferromagnetic interaction between iron(III) ions through μ-oxo-di-μ-carboxylato-bridge for complex (1), with J = ? 141.6 cm^?1.     

Silver-based coordination complexes of carboxylate ligands: crystal structures,luminescence and photocatalytic properties

The complexes [Ag₄(dpe)₄]·(btec) (1) and [Ag₄(bpy)₄]·(btec)·12H₂O (2) (dpe = 1,2-di(4-pyridyl)ethylene, bpy = 4,4′-bipyridine, H₄btec = 1,2,4,5-benzenetetracarboxylic acid) have been synthesized in aqueous alcohol/ammonia by slow evaporation at room temperature and characterized by elemental analysis, single-crystal X-ray diffraction, FTIR, UV–Vis and luminescence spectroscopies. Both complexes are composed of 1D infinite cationic [Ag/dpe(bpy)] _n ⁿ⁺ chains and discrete btec^4? anions. Their three-dimensional supramolecular structures are built up of cationic sheets formed from [Ag/dpe(bpy)] _n ⁿ⁺ units via weak Ag…Ag and Ag…N interactions, plus anionic btec^4? sheets featuring electrostatic, π–π and hydrogen bonding interactions. Both complexes exhibited photocatalytic activity for the decomposition of methyl orange under UV light irradiation.     

Synthesis, crystal structures, and magnetic properties of two three-dimensional octacyanotungstate(IV)- based bimetallic frameworks with 4,4′-bipyridine dioxide (4,4′-dpdo)

The reaction of [HN(n-C4H9)3]3[WV(CN)8]·4H2O, 4,4′-bipyridine dioxide(4,4′-dpdo), and MnCl2·4H2O or CuCl2·2H2O gives two new three-dimensional octacyanometalate-based bimetallic assemblies, {[Mn2 (4,4′-dpdo)(H2O)4] [WIV(CN)8]}·6H2O (1) and {[Cu2(4,4′-dpdo)(H2O)][W(CN)8]}·CH3OH·H2O (2). Compound 1 crystallizes in the orthorhombic system, space group P21212 with cell constants a=10.397(2) -, b= 11.321(2) -, c=12.295(3) - and Z=2, whereas 2 crystallizes in the monoclinic system, space group P21/c with cell con...     

Influence of solvent environment using the CPCM model on the H-bond geometry in the complexes of phosphorus acids with DMSO

Quantum chemical calculations of structure and energies of various H-bonded complexes of phosphoric, phosphorous and methylphosphonic acids and their dimers with dimethylsulfoxide (DMSO), i.e., (acid) _n –DMSO and acid–(DMSO) _m for n = 1, 2 and m = 2, 3 have been carried out. The polar solvent effect is taken into account by using the CPCM model. It has been found that in DMSO environment the H-bonds in all complexes of investigated acid with DMSO are sizably stronger than the ones in the gas phase. At B3LYP-CPCM computation, the H-bonds between all investigated acid dimers and DMSO are significantly shorter than those found for complexes of corresponding acids with other compositions. The H-bonding interaction in acid–(DMSO) _m for m = 1–3 becomes slightly weaker with increasing number DMSO molecules. The strength of the H-bond in all investigated complexes increases in the series of acids: (HO)₂MePO < (HO)₂P(O)H < H₃PO₄. Additionally, quantum theory of ‘atoms in molecules’ and natural bond orbitals method have been applied to analyze H-bond interactions.     

Synthesis,spectral and thermal studies on dicarboxylate-bridged palladium(II) coordination polymers. Part II

The synthesis and thermal behavior of the new [Pd(fum)(bipy)] _n ·2nH₂O (1), [Pd(fum)(bpe)] _n ·nH₂O (2) and [Pd(fum)(pz)] _n ·3nH₂O (3) {bipy = 4,4′-bipyridine, bpe = 1,2-bis(4-pyridyl)ethene and pz = pyrazine} fumarate complexes are described in this work as well their characterization by IR and ¹³C CPMAS NMR spectroscopies. TG curves showed that the compounds released organic ligands and lattice water molecules in the temperature range of 46–491 °C. In all the cases, metallic palladium was identified as the final residue.     

Photochemical properties of mixed-ligand complexes europium carboxylates

The photochemical behavior of mixed-ligand complexes of europium carboxylates with nitrogen-and phosphorus-containing neutral ligands of island and dimer types, Eu(L)₃ · xD · nH₂O and [Eu(L)₃ · xD]₂ · nH₂O (L is the trifluoroacetate, toluate, or cinnamate anion), was studied. During UV irradiation of the complexes of europium carboxylates with 1,10-phenanthroline and 2,2′-dipyridyl, a luminescence buildup was observed. EPR measurements demonstrated that the observed buildup of luminescence from europium occurs in parallel with the increase of the concentration of radical anions formed from neutral ligands.