Alkylation of naphthalene with n-butene catalyzed by liquid coordination complexes and its lubricating properties

With the development of coal chemical industry,large amounts of naphthalene and n-butene are produced,and converting them into high value-added products through alkylation has gained particular importance and interest.In this work,liquid coordination complexes(LCCs)were used as acid catalysts for the first time in the naphthalene alkylation reaction under mild conditions to obtain multibutylnaphthalenes with high yield.Various reaction conditions were thoroughly investigated.The LCC consisting of urea and AlCl_(3) showed excellent catalytic performance under optimal reaction conditions,giving 100%conversion of naphthalene and 99.66%selectivity towards multi-butylnaphthalenes.Combining the catalyst properties and catalytic results,a plausible reaction mechanism was proposed.The lubricating properties of the synthesized products were investigated for their potential application as lubricating base oils.The synthesized multi-butylnaphthalenes showed comparable physicochemical properties and tribological performances as the commercial cycloalkyl base oil.

Syntheses,Structures,and Properties of Two Cobalt(Ⅱ)Coordination Complexes Based on(Fluorene-9,9-diyl)dipropanoic Acid and 1,3-Bis(imidazol-1-yl)butane Ligands

Two new cobalt(II) coordination complexes, namely [Co(HL)_2(biim)(H_2O)_2]_n·n H_2O(1) and [Co(Et L)_2(biim)]_n·3 n(H_2O)·2 n(Et HL)(2)(H_2L =(fluorene-9,9-diyl)dipropanoic acid, biim = 1,3-bis(imidazol-1-yl)butane), have been synthesized using the same starting reactants but different solvent medium. The two complexes exhibit distinctly different structures. Compound 1 exhibits a one-dimensional linear chain structure. However, complex 2 reveals a one-dimensional zigzag chain structure. Thermogravimetric analyses(TGA) and luminescent properties of these two complexes have been discussed.

Synthesis and Crystal Structure of Two Coordination Complexes Based on H_(2)dpa and Tmd Ligands

Two new transition metal compounds, [Mn(dpa)2(tmd)2]n (1, H2dpa = 4-hydroxy-phenyl-acetic acid, tmd = 4,4-trimethylenedipyridine) and [Co4(dpa)6(tmd)4(H2O)4]n·nH2O·nCl2 (2), have been synthesized by hydrothermal synthesis. Compound 1 crystallizes in the monoclinic system, space group P21/n with a = 9.828(3), b = 17.493(5), c = 11.616(4), β = 110.146(6)o, V = 1874.9(10)3, C42H42MnN4O6, Mr = 753.74, Z = 2, Dc = 1.335 g/cm3, μ = 0.406 mm–1, F(000) = 790, the final R = 0.1047 and wR = 0.2021 for 2698 observed reflections (I > 2σ(I)). Compound 2 crystallizes in the monoclinic system, space group P21/c with a = 11.7214(13), b = 17.1582(19), c = 24.625(3), β = 103.055(3)o, V = 4824.4(9)3, C100H104Cl2Co4N8O23, Mr = 2094.55, Z = 2, Dc = 1.443 g/cm3, μ = 0.809 mm–1, F(000) = 2180, the final R = 0.0550 and wR = 0.0673 for 4104 observed reflections (I > 2σ(I)). These complexes were characterized by elemental analysis, IR spectroscopy, and X-ray single-crystal diffraction. The structural analyses show that the two compounds are both one-dimensional chain structures. However, compounds 1 and 2 form threedimensional supramolecular structures by hydrogen bonds, respectively.

Two 2D uranyl coordination complexes showing effective photocatalytic degradation of Rhodamine B and mechanism study

Two new hydrostable two-dimensional(2 D) uranyl coordination complexes [(UO_(2))_(5)(μ_(3)-O)_(2)(nbca)_(2)].7 H_(2)O(1) and [(UO_(2))_(3)(nbca)_(2)(H_(2)O)_(3)]·2 H_(2)O(2)(H_(3) nbca=5-nitro-1,2,3-benzenetricarboxylic acid) were hydrothermal synthesized.Single-crystal structural refinements reveal that both of the two complexes were formed by the packing of 2D uranyl coordination sheets via the hydrogen bonds.The nbca ligand coordinating to the uranyl polyhedron centers constructed the 2D sheets.There are UO8 hexagonal bipyramids and UO7 pentagonal bipyramids in 1 while only U07 pentagonal bipyramids in 2.Photocatalytic degradation of rhodamine B(RhB) in aqueous solution was studied.Complex 2 possesses better performance than 1 with 96.2 % of the RhB was degraded in only 60 min.Mechanism studies reveal that the dissolved oxygens are essential to the RhB degradation.The photocurrent density of 2 is more stable than that of 1,which indicating the stronger ability to separate photoexcited electrons and hole pairs of 2.

A Theoretical Study of Tris-(o-benzoquinonediimine)-First-Row Divalent Transition Metal Complexes

The ligand o-phenylenediamine (opda) and its oxidized form, o-benzoquinonediimine (bqdi), act as a fascinating candidate coordinating toward transition metal ions leading to the photochemical hydrogen production in absence of photosensitizers. Herein, we report the systematic study of the interaction between the oxidized form bqdi ligand, tris-(o-benzoquinonediimine) with divalent first-row transition metal series using DFT calculations. The lowest energy structures, bond length, binding energies, frontier molecular orbital analysis, natural bond orbitals, and global reactivity descriptor were calculated using B3LYP/6-311G(d,P) level of theory. The time dependent-DFT at the CAM-B3LYP/6-311+G(d,p) level of theory was applied to determine the electronic structures and the optical spectra. The theoretical binding trend of the divalent first-row transition metal series is decreasing as follows: Cu >Ti > V > Co > Ni > Fe > Cr > Zn >Mn. Among them, the binding potency of iron (II) by the bqdi ligand was not predominantly sturdy as compared to other first-row divalent transition metal ions. The origin of strong coordination with Fe(II) is attributed to its extra capability to induce covalent coordination of bqdi ligands. The complex exhibited two strong peaks at 370 nm and 452 nm, due to the HOMO-3 to LUMO+1 and HOMO-1 to LUMO transitions, respectively. Natural bond orbital analysis showed that the major interaction happens between the N lone pair electrons of the ligand with an anti-bonding orbital of metal ions, in which Ti showed the highest interaction energy than other metal ions. The present systemic DFT study of bqdi ligands with the first-row transition metals strongly encourages the future establishment of photochemical hydrogen production in absence of photosensitizers.

Syntheses,Crystal Structures and Properties of Mn(Ⅱ) and Co(Ⅱ) Coordination Complexes Based on 1,10-Phenanthroline Derivative

Two new coordination complexes[Mn(L)_(2)(DNSA)](1) and[Co(L)(1,4-bdc)]_n (2) have been achieved under hydrothermal conditions (H_(2)DNSA=3,5-dinitro-salicylic acid,1,4-bdc=1,4-benzenedicarboxylic acid and L=2-(2-fluoro-6-fluorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline).1 crystallizes in monoclinic,space group P2_1/c with a=15.871(3),b=17.274(4),c=16.078(3)A,β=113.03(3)^(o),V=4056.6(16)A^(3),Z=4,C_(45)H_(22)Cl_(2)F_(2)Mn N_(10)O_(7),M_(r)=978.57,D_(c)=1.602 g/cm^(3),F(000)=1980,μ(Mo Ka)=0.536 mm^(–1),R=0.0437 and w R=0.1065.2 belongs to the monoclinic system,space group C2/c with a=14.665(2),b=30.856(4),c=11.237(2)A,β=111.166(2)^(o),V=4742.0(12)A^(3),Z=8,C_(27)H_(14)Cl Co FN_(4)O_(4),M_r=517.80,D_(c)=1.602 g/cm^(3),F(000)=2312,μ(Mo Ka)=0.889 mm^(–1),R=0.0364 and w R=0.0862.The central Mn(II) ion in 1 is six-coordinated by four nitrogen atoms from two L ligands and two oxygen atoms from one DNSA anion.In 2,the two kinds of 1,4-bdc ligands link neighboring Co(II) atoms to yield a two-dimensional layer structure.The luminescence of 1 has been studied in detail.Moreover,thermal behaviors of 1 and 2 are also investigated.

Two New Coordination Complexes Based on 2,2'-H2biimidazole: Synthesis, Structure, Luminescent Property and Theoretical Calculation

Two new coordination complexes[Cd(L)2(1,2,3-HBTC)]·3H2O(1)and{[Zn(L)(1,2-BDC)]-H2O}n(2)were synthesized under hydrothermal conditions(1,2,3-H3 BTC=1,2,3-tricarboxybenzene,1,2-H2 BDC=1,2-dicarboxybenzene and L=2,2’-H2 biimidazole).1 crystallizes in monoclinic,space group P21/c with a=12.256(5),b=11.620(5),c=17.479(5)A,β=95.548(5)°,V=2477.6(16)A^3,Z=4,C21H22N8 O9 Cd,Mr=642.86,Dc=1.724 g/cm^3,F(000)=1296,μ(MoKa)=0.950 mm^-1,R=0.0546 and wR=0.1724.2 belongs to the monoclinic system,space group P21/c with a=7.408(4),b=20.743(10),c=10.194(5)A,β=95.648(6)°,V=1477.3(12)A^3,Z=4,C14H12N4 O5 Zn,Mr=381.65,Dc=1.716 g/cm3,F(000)=776,μ(MoKa)=1.698 mm^-1,R=0.0574 and wR=0.1632.The central Cd(Ⅱ)ion in 1 is coordinated with five atoms,forming a slightly distorted square-pyramidal geometry.The central Zn(Ⅱ)ion in 2 is four-coordinated by two nitrogen atoms from one L ligand and two oxygen atoms from two different 1,2-BDC anions.In addition,luminescent property of 1 has been investigated,and natural bond orbital(NBO)analysis of 2 has been calculated by the B3LYP/LANL2DZ method.

Synthesis,Crystal Structure and Luminescent Property of a New Indium(Ⅲ)Coordination Polymer

A new coordination complex [In(pda)1.5(bpy)]_n(1, H_2pda = 1,4-phenylenediacetic acid, bpy = 2,2?-bipyridine) has been synthesized under hydrothermal conditions and characterized by IR spectrum, elemental analysis, PXRD and single-crystal X-ray diffraction analysis. Crystal data for the title complex are as follows: monoclinic system, space group P21/n with a = 11.8015(7), b = 15.9551(10), c = 11.8858(8) ?, β = 94.844(6)o, V = 2230.0(2) ?~3, Mr = 559.25, Z = 4, F(000) = 1124, Dc = 1.666 g/cm3, μ(Mo Kα) = 1.106 mm-1, R = 0.0269 and wR = 0.0569 for 4534 observed reflections with I > 2σ(I). Complex 1 displays a 3D supermolecular structure based on the 1D zizag chains. Fluorescence spectrum measurement indicates that complex 1 shows strong fluorescence emission with a maximum peak at 447 nm in the solid state at room temperature.

Hydrothermal Synthesis,Crystal Structure and Spectral Characterization of a New Copper Isopolytungstate: [Cu(phen)_3][W_6O_(19)]

An unusual inorganic-organic hybrid hexatungstate complex [Cu(phen)3][W6O19] 1 (C36H24 CuN6O19W6, Mr = 2011.20) was hydrothermally synthesized and characterized by single- crystal X-ray diffraction, IR spectrum, UV-VIS spectrum and elemental analyses. This compound crystallizes in the monoclinic system, space group C2/c with a = 19.1005(11), b = 11.2585(11), c = 20.2867(15) , β = 102.177(2)o, V = 4264.4 3, μ(MoKa) = 16.691 mm–1, Dc = 3.133 g/cm3, Z = 4, F(000) = 3628, the final R = 0.0338 and wR = 0.0798 for 4090 observed reflections with I > 2σ(I). The result of structure determination shows that the crystal structure is constructed from [W6O19]2– cluster anions and [Cu(phen)3]2+ complex fragments, which are held together into a three-dimen- sional network through hydrogen-bonding interactions.

Complex coordinate rotation method based on gradient optimization

In atomic,molecular,and nuclear physics,the method of complex coordinate rotation is a widely used theoretical tool for studying resonant states.Here,we propose a novel implementation of this method based on the gradient optimization(CCR-GO).The main strength of the CCR-GO method is that it does not require manual adjustment of optimization parameters in the wave function;instead,a mathematically well-defined optimization path can be followed.Our method is proven to be very efficient in searching resonant positions and widths over a variety of few-body atomic systems,and can significantly improve the accuracy of the results.As a special case,the CCR-GO method is equally capable of dealing with bound-state problems with high accuracy,which is traditionally achieved through the usual extreme conditions of energy itself.

Determination of Lisinopril in Bulk and Pharmaceutical Formulations by Cloud Point Extraction—A Green Method

A sensitive and eco-friendly method was developed for the spectrophotometric determination of Lisinopril (LSP) in bulk and pharmaceutical formulations by cloud point extraction technique. The method was based on the formation of a blue-colored coordination complex between Lisinopril (LSP) and Cobalt Thiocyanate (CTC) at a suitable pH. The Complex in aqueous medium was extracted into surfactant layer by cloud point extraction using a non-ionic surfactant Triton X-114 and then the surfactant layer was dissolved in a suitable volume of ethanol and the amount of Lisinopril was determined spectrophotometrically at a wavelength of 625 nm. The conditions like concentration of the drug, concentration of CTC and of Triton X-114, PH, etc. were optimized by OFAT (One Factor At a Time) method. The linear range of calibration curve was 1 - 6 μg/ml and the linear regression equation with a correlation coefficient of 0.99996 was y = 0.0021 + 0.084x. Preconcentration and enrichment factors were found to be 100 and 3.12 respectively, achieving the detection limit of 0.0588 μg/ml. The proposed method was successfully applied for the determination of LSP in the drug formulations. The obtained values were in agreement with the values as quoted by the manufacturers.

The Effects of Oxidation States and Spin States of Chromium Interaction with <i>Sargassum Sp</i>.: A Spectroscopic and Density Functional Theoretical Study

The study of various oxidation states of chromium with Sargassum sp. is of particular interest since hexavalent chromium is reduced to trivalent chromium in an aqueous solution. In this study, a systematic density functional theory (DFT) calculations were performed to study the interactions of transition metal chromium ion with different oxidation states and spin states with the Sargassum sp. decorated with carboxylate (acetate) at the wB97XD/6-311++ G(d,p) level of theory. The structures and binding energies of chromium metal-carboxylate complexes at various oxidation states and spin states in gas phase were examined. The coordination strength of Cr(VI) with the acetate ligand was predominantly the strongest compared to the other oxidation states. Vibrational frequency analysis, for the homoleptic monomers of tris [CrIII(AC)3]0 and [CrVI(AC)3]3+ complexes, illustrate good harmony with the experimental and theoretical calculated frequencies. Using the time-dependent DFT (TD-DFT) at the level of CAM-B3LYP/6-311++G(d,p), the vertical excitation energies were obtained. The stabilization energies derived using the second order perturbation theory, Eij(2), of NBO analysis confirmed the greater charge transfer for the observed trends in the metal binding. The calculated binding energies (ΔE) and interactions energies SEij(2) favor the formation of [CrVI(AC)3]3+ complexes. The findings of this study identify efficient electronic factors as major contributors to the metal binding affinities, with promising possibilities for the design of metal-ligand complexes and sensing of the metal ions.

A novel Ga(Ⅲ)coordination complex as an efficient sensitizer for enhancing photocatalytic activity of TiO_(2)/rGO nanocomposite

Narrow solar-light response range and rapid charges recombination are the main technical barriers in TiO_(2) photocatalysis technology.To overcome these restrictions,in this work we synthesized a novel binuclear gadolinium(Ⅲ) coordination complex,[Gd_(2)(DPDB)_6(DMF)_6(H_(2)O_()2)](DPDB=[(4-dimethylamino)phenyldiazenyl] benzenesulfonate),which was used as an inorganic sensitizer for boosting the visible light-harvesting and quantum efficiency of TiO_(2) supported-reduced graphene oxide(rGO) nanocomposite.Crystal structure of [Gd_(2)(DPDB)_6(DMF)_6(H_(2)O)_(2)](Gd-CMP) was determined from single-crystal X-ray diffraction data,which indicates three-dimensional(3D) supramolecular architecture through hydrogen bonding and CH…π_(ph) interactions.The prepared nanohybrid(Gd-CMP/TG) reveals significantly enhanced visible-light-induced photocatalytic activity for degradation of acetaminophen(ACT).The complete removal of 10 mg/L ACT is achieved over Gd-CMP/TG,and the corresponding rate constant of ACT degradation of nanohybrid is 40-fold higher than that of bare TiO_(2).In prepared ternary nanohybrid,metal-coordination sensitizer(Gd-CMP) acts as an electron donor,and at the same time,rGO serves as an electron acceptor,and the synergistic effect between them efficiently enhances charges separation and inhibits e/h pair recombination in the hybridized species.The radical scavenger tests indicate that the photo-induced O_(2)^(-·) radicals dominate ACT degradation.On the basis of the experimental results and calculated energy of electronic levels,a possible mechanism for the improved photocatalytic activity is discussed.

Challenging the limitation:Synthesis and application of complexes with the highest carbon coordination number in plane

Subject Code:B02With the support by the National Natural Science Foundation of China and the National Basic Research Program of China,the research team led by Prof.Xia Haiping(夏海平)of Xiamen University described the first example of CCCCC pentadentate chelate with all binding atoms being carbon atoms.This result represents a new record of planar carbon coordination number for a transition metal,which was

Whither Second-Sphere Coordination?

The properties of coordination complexes are dictated by both the metals and the ligands.The use of molecular receptors as second-sphere ligands enables significant modulation of the chemical and physical properties of coordination complexes.In this minireview,we highlight recent advances in functional systems based on molecular receptors as second-sphere coordination ligands,as applied in molecular recognition,synthesis of mechanically interlocked molecules,separation of metals,catalysis,and biomolecular chemistry.These functional systems demonstrate that second-sphere coordination is an emerging and very promising strategy for addressing societal challenges in health,energy,and the environment.

Fluorescent Recognition of Small Organic Molecules Based on Supramolecular Aggregation/Deaggregation of Planar Cu(Ⅱ)Coordination Complex

A Cu(II)coordination complex(1)with Schiff ligand derived from diaminomaleonitrile was synthesized and characterized,in which the ligand is rigid,planar and conjugated.The complex 1 displays an interesting fluorescent property relative to solvents which can be turned-on by CH_(2)Cl_(2) and CHCl_(3) solvent molecules.The mechanism of this selective fluorescence emission has been studied based on the crystal structure and the spectrum analysis.The tuning on and off fluorescence of complex 1 can be controlled by the process of supramolecular aggregation/deag-gregation in different solvents.

Managing Coordination Complexity in the Remanufacturing of Aircraft Engines

The complexity of communication and coordination stemming from teams responsible for adjusting interdependent parameters of components is a fundamental feature in the aircraft engine remanufacturing engineering project. To manage coordination complexity, the features of the remanufacturing process of aircraft engine are analyzed and a systematic method is presented to measure and optimize the dependency between coupled components.Furthermore, quantitative models are built based on Design Structure Matrix(DSM) models to measure dependency strengths related to the parameter features of the components. Also, a two-stage DSM clustering criteria is used to reduce the complexity of an organization. An industrial example is provided to illustrate the proposed models. The results showed that the proposed approach can reduce total coordination complexity.

Trefoil-shaped metallacycle and metallacage via heteroleptic self-assembly

Template-oriented multi-component synthesis method has been proven to be an exceedingly reasonable and excellent method for the synthesis of giant two-dimensional(2D)and three-dimensional(3D)supramolecules,but designing and constructing heteroleptic and controllable self-assembly without unexpected by-products remains a challenge.Here we report two discrete trefoil-shaped metallacycle S1 and metallacage s2 by heteroleptic self-assembly using one hexaphenylbenzene core ligand and two capping ligands.The 2D trefoil-shaped metallacycle S1 could resemble the emblem of the classic'Mitsubishi motif.The use of template-oriented ligand and bent spacer ligand promotes the quantitative formation of the desired 3D trefoil-shaped metallacage S2.The formed metallacage S2 possesses a molecular weight up to 36 kDa,diameter 6.6 nm and height 3.0 nm.All supramolecular coordination complexes were fully characterized by NMR spectroscopy(^(1)H NMR,2D COSY,2D NOESY,2D DOSY),high-resolution electrospray ionization mass sectrometry ESI-MS.ESI-TWIM-MS,TEM and AFM.

Photoacoustic imaging-guided chemo-photothermal combinational therapy based on emissive Pt(Ⅱ)metallacycle-loaded biomimic melanin dots

Pt(Ⅱ)-based metallacycles,as an important family of supramolecular coordination complexes(SCCs),have exhibited excellent antitumor activity at the cell level.However,the biomedical applications of Pt(Ⅱ)-based metallacycles for animal studies are still hindered by their poor stability,non-targeted tumour,and lack of detectable feedback for evaluating therapeutic progress.Herein,we propose a strategy that introduces melanin dots as a biomedical platform to load bright-emission Pt(Ⅱ)-based metallacycles,thereby constructing a theranostic agent that enables photoacoustic imaging(PAI)-guided chemo-photothermal combinational therapy.Melanin dots act as a protective carrier to preserve the integrity of Pt(Ⅱ)-based metallacycles before uptake by tumour tissues.Meanwhile,the PAI signal from melanin dots furnishes more comprehensive information on the tumour.Moreover,the heat generated after NIR laser irradiation can not only trigger the apoptosis of tumour cells but also promote the deeper penetration of Pt(Ⅱ)-based SCCs into tumour tissue,thus enhancing the efficiency of chemotherapy.

Manganese(Ⅱ)and Copper(Ⅰ)Compounds Based on Two Derivatives of Imidazo[1,5-a]pyridine:Synthesis,Structures,Magnetic Properties,and Catalytic Activity

The utilization of 2,6-bis(imidazo[1,5-a]pyridin-3-yl)pyridine(bipp)and 3-(pyridin-2-yl)imidazo[1,5-a]pyridine(pip)in the compounds of manganese(Ⅱ)and copper(Ⅰ)ions is presented.Two complexes,[Mn(bipp)(SO_(4))(H_(2)O)]n(1)and[Cu(pip)_(2)]ClO_(4)(2),were prepared with different characteristics in structure.Compound 1 exhibits a one-dimensional chain topology,and 2 is a homoleptic Cu(Ⅰ)complex.The dc magnetic susceptibility investigations reveal the antiferromagnetic(AF)MnⅡ···MnⅡinteractions in complex 1.The catalytic activity of compound 2 toward ketalization reactions was studied.Complex 2 exhibits high activity for the ketalization transformations of aliphatic ketones.