Bridge-splitting of trans-[PtCl2(η2-CH2CH2)]2 by weak nucleophiles: Crystal and molecular structure of trans-[PtCl2(η2-CH2CH2)(MeCN)]

Bridge-splitting of trans-[PtCl₂(η²-CH₂CH₂)]₂, 1, by L in dichloromethane yields trans-[PtCl₂(η²-CH₂CH₂)(L)] (L = THF, 2, or MeCN, 3) with bridge-splitting equilibrium constants of 0.0289 ± 0.0007 and 3601 ± 215 mol^?1 dm³, respectively, as determined by UV/Vis measurements. The reaction of 3 in MeCN with Cl^? is essentially quantitative. The crystal structure of trans-[PtCl₂(η²-CH₂CH₂)(CH₃CN)] is reported.     

Two transition metal coordination polymers constructed from 1,4-naphthalenedicarboxylate and N/O-donor auxiliary ligands: Syntheses,structures and magnetic property

Two transition metal coordination polymers (CPs), namely, Cd(1,4-NDC)(py) (1), Co₂(1,4-NDC)₂(DMF)₂ (2) (1,4-NDCH₂ = 1,4-naphthalenedicarboxylic acid, py = pyridine, DMF = N,N-dimethylformamide) have been synthesized and characterized. Compound 1 contains one-dimensional chains, which are further linked by the NDC^2 − ligands to form a three-dimensional framework with a 5,5T2 topology network. There exist two types of left-hand helical chains interconnected to each other through the Cd(II) center in compound 1. Although compound 2 has been reported previously, in this work the synthetic method of 2 is modified to obtain high quality crystals. In addition, the magnetic property of compound 2 is investigated, which shows the metamagnetic behavior induced by the external field.     

Reactivity of cyrhetrenylphosphines: Synthesis and characterization of oxides,boranes and selenides

Reaction of cyrhetrenylphosphines, of general formula (η⁵-C₅H₄PR₂)Re(CO)₂L (R = Ph, L = CO (1); R = Cy; L = CO (2); R = Ph, L = PMe₃ (3) and R = Ph, L = P(OMe)₃ (4)), with H₂O₂, BH₃·THF or selenium gives the respective cyrhetrenylphosphine oxides, boranes and selenides. These species were characterized by standard spectroscopic techniques (FT-IR, ¹H and ³¹PNMR). Based on the ³¹P⁷⁷Se coupling constant (¹J_P-Se) of the phosphine-selenides, we established the following order of basicity of the parent cyrhetrenylphosphine 2 > 3 > 4 > 1. We also confirmed the opposite electronic effects of the cyrhetrenyl and ferrocenyl groups attached to a –PR₂ unit. Finally, phosphine selenides 2c and 4c were structurally characterized by X-ray diffraction.     

Synthesis,luminescence, and structural characterization of Zn and Cd coordination polymers of flexible bis(imidazolyl) derivatives

Coordination polymers [Zn(imc)(L¹)] · H₂O, (1, imc = iminodiacetate, L¹ = bis(N-imidazolyl)methane) [Zn(hba)₂(L²)]₂ · EtOH · 3H₂O, (2, hba = p-hydroxybenzoate, L² = bis(N-benzimidazolyl)methane), [Cd(mal)(H₂O)(L³)](3, L³ = 1,4-bis(N-imidazolyl)butane, mal = maleate) have been prepared and structurally characterized. Complex 1 consists of hexa-coordinated central Zn ions and exhibits 2D network structure. The Zn atoms in 2 have tetrahedral coordination geometry, and are linked by bis(imidazolyl) ligands into 1D chain structure. The cadmium ions in 3 are hepta-coordinated with pentagonal bipyramidal geometry. Complex 3 displays 2D grid structure. The TGA showed that the coordination polymers are stable up to 200 °C. All the three complexes are emissive at room temperature in their solid state.     

Measurement and correlation of vapor–liquid equilibra for cyclohexane + ethylene glycol monoisopropyl ether and cyclohexane + ethylene glycol monoisobutyl ether systems

Ethylene glycol monoisopropyl ether (iC₃E₁) and ethylene glycol monoisobutyl ether (iC₄E₁) are nonionic surfactants which have been attracting considerable attention due to inter and intra-molecular association, related to the presence of O and OH in the same molecule. Binary isothermal vapor + liquid equilibrium data were measured for cyclohexane + ethylene glycol monoisopropyl ether and cyclohexane + ethylene glycol monoisobutyl ether systems at four different temperatures ranging from 303.15 K to 333.15 K at 10 K intervals. A static apparatus was used in this study. Two systems show positive deviation from Raoult's law and no azeotrope. The experimental data were correlated well with Peng–Robinson–Stryjek–Vera equation of state using Wong–Sandler mixing rule.     

Design,structure and magnetic properties of a novel one-dimensional Mn(II) coordination polymer constructed from 4-pyridyl-NH-1,2,3-triazole

A one-dimensional manganese(II) complex, [Mn(L₂)]_n (1, HL = 4-pyridyl-NH-1,2,3-triazole), has been hydrothermally synthesized at 120 °C. In the structure of 1, the Mn(II) ions are octahedral coordinated and further bridged by L⁻ ligands, forming a rigid 1D ribbon coordination chain. Varieties of supramolecular interactions, such as hydrogen bonds and CH ⋯ π interactions, play an important role on the stabilization of the structures. As revealed by magnetic measurement, complex 1 displays weak antiferromagnetic interaction with θ = –4.83 K, the best fit using Fisher's 1D Heisenberg model gives the intrachain magnetic coupling constant J = –0.21 cm^− 1 above 30 K due to the neighboring Mn(N–N)₂Mn rings twisted in the angle of almost 90°.     

One-dimensional supramolecular assembly of an Mn12 single molecule magnet by ligand interactions

A new Mn₁₂ complex was synthesized using ligand substitution reaction of Mn₁₂–OAc with 4-(thiophen-3-yl)benzoic acid and complex’s structural and magnetic properties were analysed. [Mn₁₂O₁₂(O₂CC₆H₄C₄H₃S)₁₆(H₂O)₃]·14CH₂Cl₂ (1) crystallized in the P2₁/c space group. Intermolecular π–π interactions between phenyl and thiophene rings of two adjacent Mn₁₂ molecules result in one-dimensional supramolecular assembly of 1 in the crystal. On the other hand, steric repulsion between the neighbouring molecules causes unusual ligand arrangement and coordination geometry of Mn(III) ion with five coordination. The ac magnetic study of 1 gives U_eff = 69.98 K and 1/τ₀ = 1.456 × 10⁸ s^?1 and dc reduced magnetization measurement gives S = 10, g = 1.95 and D = ?0.425 cm^?1 showing that outer ligand distortion has little effect on the magnetic properties.     

Syntheses,structures and luminescence of two cadmium entangled coordination polymers based on bis(imidazole) and biscarboxylate ligands

Two entangled coordination polymers [Cd₂(bib)(bdc)₂]_n (1) and [Cd₂(bib)(bda)₂]_n (2) were synthesized by the hydrothermal reaction (bib = 1,4-bis(2-methyl-imidazol-1-yl)butane, bdc = 1,2-benzenedicarboxylate, bda = 1,4-benzenediacetate). 1 exhibits an unusual 6-connected self-catenated 3D network based on Cd₂(COO)₂ dimer with the point symbol of (4⁴·6¹⁰·8). 2 exhibits a 3-fold interpenetrating 3D pcu network based on Cd₂(COO)₂ dimer. The different conformations of bib ligands (the anti–anti–anti conformation in 1 and gauche–anti–gauche conformation in 2) play the key role in the construction of different structures in 1 and 2. The luminescence and thermal stability were investigated.     

Activity of Mo(II) allylic complexes supported in MCM-41 as oxidation catalysts precursors

[Mo(η³-C₃H₅)X(CO)₂(NCCH₃)₂] (X = Br, 1a; X = Cl, 1b) complexes reacted with the bidentate ligand RNC(Ph)–C(Ph)NR, R = (CH₂)₂CH₃ (DAB, 2) affording [Mo(η³-C₃H₅)X(CO)₂(DAB)] (X = Br, 4a; X = Cl, 4b), which were characterized by elemental analysis, FTIR and ¹H and ¹³C NMR spectroscopy. The modified silylated ligand RNC(Ph)C(Ph)NR, R = (CH₂)₃Si(OCH₂CH₃)₃ (DAB–Si, 3), was used to immobilize the two complexes in MCM-41 (MCM) mesoporous silica. The new materials were characterized by powder X-ray diffraction, N₂ adsorption analysis, FTIR and ²⁹Si and ¹³C CPMAS solid state NMR spectroscopy. Both the materials and the complexes were tested in the oxidation of cyclooctene and styrene and behaved as active catalyst precursors for cyclooctene and styrene epoxidation with TBHP (t-butylhydroperoxide), leading selectively to epoxides with high conversions and TOFs. Although the homogeneous systems reach 100% conversion of cyclooctene and slightly less for styrene, the loss of catalytic activity in the heterogeneous systems is small, with a 98% conversion of styrene achieved by the chloride containing material.     

Novel two-dimensional Co(II) and Cd(II) coordination polymers with intriguing net topologies

Three new two-dimensional coordination polymers were constructed from 2,6-bis(imidazole-1-yl)pyridine (2.6-bip), terephthalic acid (1,4-bdcH₂), and M(NO₃)∙nH₂O (M = Co, Cd). [M(2,6-bip)(1,4-bdc)] (1: M = Co; 2: M = Cd) were prepared under hydrothermal condition, whereas [Cd(2,6-bip)(1,4-bdc)∙xDMF] (3) was obtained under solvothermal condition in DMF solvent. Single-crystal X-ray analyses revealed the first example of a 2D 4-connected net of 6⁶ topology in 1 and 2 and a rare 2D 4,5-connected net of 4,5 L20 topology in 3. All these complexes were thermally robust and emissive in solid-states. This work confirmed the versatility of using hingelike 2,6-bip as a linker and the importance of solvent effect in the process of framework formation.     

Controlled synthesis of lanthanide–lithium inverse crown ether complexes

An ytterbium–lithium inverse crown ether complex stabilized by amine-bridged bis(phenolate) ligands (LYbBr)₂(μ₄-O)(μ₃-Li) (1) [L = Me₂NCH₂CH₂N{CH₂-(2-O- C₆H₂-Bu^t₂-3,5)}₂] was isolated as a byproduct from the reaction of LYbCl(THF) with CH₃Li in THF in a very low isolated yield. Further study revealed that the inverse crown ether complexes can be synthesized in a controlled manner by the reaction of bis(phenolate) lanthanide chloride with an in situ mixture of n-BuLi with water in THF. A second inverse crown ether complex (L′YbCl)₂(μ₄-O)(μ₃-Li) (2) [L′ = Me₂NCH₂CH₂N{CH₂-(2-O-C₆H₂-Bu^t-3-Me-5)}₂] was prepared in high isolated yield and well characterized.     

Syntheses and structures of cadmium(II) and cobalt(II) coordination polymers based on 1,1′-(2,2′-oxybis(ethane-2,1-diyl))bis(1H-imidazole) and carboxylate ligands

Two novel coordination polymers containing Cd(II) and Co(II) metals, connected via 1,1′-(2,2′-oxybis(ethane-2,1-diyl))bis(1H-imidazole) (L) ligand, have been synthesized. Compound [Cd(L)₂(p-BDC)] · 2H₂O (1) (p-BDC = 1,4-benzenedicarboxylate anion) is a three-dimensional interdigitated supramolecular architecture. Compound [Co(L)(BTCA)_0.5] (2) (BTCA = 1,2,3,4-butanetetracarboxylate anion) possesses a unique (3,4)-connected 3D framework with (8³)₂(8⁵ · 10) topology.     

A new 2D 5-connected coordination polymer based on 3,4-bis(pyridin-4-ylmethoxy)benzoic acid ligand

A new 2D 5-connected coordination polymer [Zn₃(HL²)(1,4-bdc)₃] (1) (HL² = 3,4-bis(pyridin-4-ylmethoxy)benzoic acid, 1,4-H₂bdc = 1,4-benzenedicarboxylate) has been hydrothermally constructed using HL², 1,4-bdc ligands as linear linkers and Zn₃-clusters as 5-connected nodes. In addition, powder X-ray diffraction, photoluminescent property and thermogravimetric analysis for 1 are investigated in detail.     

LiBa1.5[B5O8(OH)3]: A new 1-D metal borate chain constructed from B5O9(OH)36 − cluster units

A new mixed metal borate LiBa_1.5[B₅O₈(OH)₃] (1) has been hydrothermally synthesized and structurally characterized by FT-IR spectroscopy, powder X-ray diffraction, single crystal X-ray diffraction, and thermogravimetric analysis, respectively. 1 crystallizes in the monoclinic system, space group C2/c, a = 11.2839(7) Å, b = 7.3974(4) Å, c = 20.7151(13) Å, β = 103.392(6)°, V = 1682.10(17) ų and Z = 8. The structure consists of infinite one-dimensional (1-D) borate chains constructed from B₅O₉(OH)₃^6 − cluster units. These BO chains are further linked by the Ba^2 + and Li⁺ cations to form a 3-D framework.     

Structural characterization of ferromagnetic bridged-acetato and -dichlorido copper(II) complexes based on bicompartmental 4-t-butylphenol

The reaction of Cu(II) salts with 2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4-t-butylphenol (L^t-Bu-OH) afforded two bridged-phenoxido/hydroxido complexes. The dinuclear bridged acetate species [Cu₂(μ-L^t-Bu-O)(μ-CH₃COO)](PF₆)₂ (1) and the 1D polymeric doubly-bridged-chlorido {[Cu₂(μ-L^t-Bu-OH)(μ-Cl)₂](ClO₄)₂·4H₂O}_n (2). The two complexes were structurally characterized. Both complexes revealed ferromagnetic interactions; moderate in complex 1 (J = + 30.8 cm^− 1) and very weak (J = + 2.25 cm⁻¹) in 2.     

Two octamolybdate-based coordination polymers with high photocatalytic activities under visible light irradiation

Two coordination polymers based on octamolybdate and 2-aminopyrazine, namely, [Cu^I₂(HL)₂(L)(β-[Mo₈O₂₆])]·3H₂O (1) and [(H₂L)₂(β-[Mo₈O₂₆])]·4H₂O (2) (L = 2-aminopyrazine), have been synthesized hydrothermally. The structures of the compounds were determined by single-crystal X-ray diffraction analyses and further characterized by infrared spectra, elemental analyses, powder X-ray diffraction analyses and thermogravimetric analyses. Compound 1 displays a double chain structure, which is extended by the intermolecular NH ⋯ O hydrogen-bonding interactions to generate a 3D supramolecular architecture. Compound 2 exhibits a discrete structure, which is connected by the intermolecular OH ⋯ O hydrogen-bonding interactions to yield a 3D supramolecular architecture. Compounds 1 and 2 display small band gaps of 1.89 and 1.66 eV, respectively. Moreover, compounds 1 and 2 exhibit high photocatalytic activities for degradation of methylene blue under visible light irradiation.     

Copolymerizations of ethylene with α-olefin-ω-ols by highly active vanadium(III) catalysts bearing [N,O] bidentate chelated ligands

The copolymerizations of ethylene with polar hydroxyl monomers such as 10-undecen-1-ol, 5-hexen-1-ol and 3-buten-1-ol were investigated by the vanadium(III) catalysts bearing bidentate [N,O] ligands (1, [PhNC(CH₃)CHC(Ph)O]VCl₂(THF)₂; 2, [PhNCHC₆H₄O]VCl₂(THF)₂; 3, [PhNCHC(Ph)CHO]VCl₂(THF)₂). The polar monomers were pretreated by alkylaluminum before the polymerization. High catalytic activities and efficient comonomer incorporations can be easily obtained by changing monomer masking reagents and polymerization conditions in the presence of diethylaluminium chloride as a cocatalyst. The longer the spacer group, the higher the incorporation of the monomer. Under the mild conditions, the incorporation level of 10-undecen-1-ol reached 13.9 mol% in the resultant copolymers was obtained. The reactivity ratios of copolymerization (r₁ = 41.4, r₂ = 0.02, r₁r₂ = 0.83) were evaluated by Fineman–Ross method. According to ¹³C NMR spectra, polar units were located both on the main chain and at the chain end. The end-hydroxylated polymers were probably obtained due to the formation of dormant species after the insertion of the comonomer followed by the chain transfer to alkylaluminum. In addition, the signals derived from polar monomer inverse insertion were detected for the first time.     

Azo dyes sulphur-bridged ruthenium–molybdenum complexes: Synthesis,spectroscopic and electrochemical characterization of [(α/β-NaiR′)2Ru(μ-S)2Mo(OH)2]

The reaction of azo dye complexes ctc-[Ru(α/β-NaiR′)₂Cl₂] (1) [α/β-NaiR′ = 1-alkyl-2-α/β-(naphthylazo)imidazole, C₁₀H₇–NN–C₃H₂NN(1)–R′, R′ = Me (2), Et (3), Bz (4)] with (NH₄)₂MoS₄ in aqueous MeOH afforded reddish violet colour mixed ligand complexes of the type [(α/β-NaiR′)₂Ru(μ-S)₂Mo(OH)₂] (2–4). In complexes 2–4 the terminal MoS bonds of the MoS₄²⁻ unit become hydroxylated and the molybdenum ion is reduced from the starting Mo^VI in MoS₄²⁻ to Mo^IV in the final product (2–4). The solution electronic spectra exhibit a strong MLCT band at 550–570 nm in DCM. Cyclic voltammograms show a Ru(III)/Ru(II) couple at 1.10–1.4 V, irreversible Mo(IV)/Mo(V) oxidations in the 1.66–1.72 V range, along with four successive reversible ligand reductions in the range −0.45 to −0.67 V (one electron), −0.82 to −1.12 V (one electron), and −1.44 to −1.90 V (simultaneously two electrons).     

Three novel bismuth-based coordination polymers: Synthesis,structure and luminescent properties

Three novel bismuth-based coordination polymers, [(CH₃)₂NH₂][Bi(pdc)(bdc)]·2DMF, [(CH₃)₂NH₂][Bi(tdc)₂]·1.5DMF and [Bi(bpdc)₂H₂O]·xGuest (compounds 1–3) (H₂pdc = 3,5-pyridinedicarboxylic acid, H₂bdc = 1,4-benzenedicarboxylic acid, H₂tdc = 2,5-thiophenedicarboxylic acid, H₂bpdc = 4,4′-biphenyldicarboxylic acid), have been successfully synthesized under solvothermal conditions and characterized by single crystal X-ray diffraction. Compounds 1 and 2, which are constructed by 9-coordinated or 8-coordinated Bi^3 +, feature three-dimensional structures with hms and dia topology, respectively. However, 5-coordinated Bi^3 + based compound 3 is a two-dimensional layered structure. Compound 1 can tune emissive performance by doping different lanthanide ions Tb^3 +, Eu^3 + and Dy^3 +. Furthermore, detection of nitro explosives is investigated. All of the compounds are characterized by elemental analysis, IR spectrum and thermogravimetric analysis.