Spectra and DNA-binding Properties of Two Novel Mixed-ligand Complexes Containing Organosulfonate

Two novel mixed-ligand complexes, [M（phen）2（ans）2]·H2O （M = Cd（Ⅱ） 1, Zn（Ⅱ） 2; phen is 1, 10-phenanthroline, and ans is 4-aminonaphthalene-1-sulfonate）, were obtained from the reaction of 1, 10-phenanthroline, sodium 4-aminonaphthalene-1-sulfonate tetrahydrate and acetate in mixed solvents. Interaction of the complexes with calf thymus DNA （ctDNA） were investigated using UV-vis absorption spectra, luminescence titrations, steady-state emission quenching by [Fe（CN）6]4 , DNA competitive binding with ethidium bromide （EB） and viscosity measurements. The experimental results indicate that there exist two interaction modes between the complexes and DNA, namely the electrostatic interaction and intercalation, with the binding constants of 1.82 × 10^5 M-1 for 1 and 4.78 ×10^4 M^- 1 for 2 in buffer of 50 mM NaCl and 5 mM Tris-HCI （pH 7.0）.

A Trinuclear Ni(Ⅱ) Mixed-ligand Complex Containing Pentadentate N-butyl-salicylhydrazide and Monodentate Imidazole:Synthesis, Characterization and Crystal Structure

A novel trinuclear nickel（II） complex [Ni3（bushz）z（Himdz）2（H20）2].2DMF （1, bushz = N-butylsalicylhydrazide, Himdz = imidazole, DMF = N,N-dimethyl-forrnamide） has been synthesized and characterized by X-ray single-crystal diffraction characterization. Complex 1 crystallizes in the monoclinic system, space group P2 1/c with a = 7.706（7）, b = 14.882（6）, c = 18.639（6） A, β = 108.08（2）°, V= 2032（1） A3, Dc = 1.525 g/cm3, Mr = 932.95, Z= 2, F（000） = 972,μ = 1.442 mm-1, the final R = 0.0359 and wR = 0.0771. The three nickel（II） atoms in 1 are arranged in a strictly linear structure and exhibit alternating square-planar and octahedral geometries. The complex is connected to form a supramolecule with an infinite three-dimensional network through intermolecular hydrogen bonds. The electrochemical studies reveal that redox of Ni3＋/Ni2＋ in the complex is a quasi-reversible process. The thermal stability of the title complex was also studied.

Syntheses and Crystal Structures of Mono-and Binuclear Copper(Ⅱ) Mixed-ligand Complexes Involving Schiff Base

The mononuclear copper（Ⅱ） complex [Cu（L）（2-AP）] 1 and binuclear copper（Ⅱ） complex [Cu（L）（py）]2 2 （L = C10H11O5NS, taurine o-vanillin, py = prydine, 2-AP = 2-aminopyridine） with mixed ligand have been synthesized and characterized by X-ray diffraction method. Crystal data for 1： orthorhombic, space group Pbca with a = 11.921（4）, b = 15.816（6）, c = 17.076（6） A, V= 3219.7（19） A^3, C15H17CuN3O5S, Z = 8, Mr = 414.92, De = 1.712 g/cm^3,μ（MoKα） = 1.520 mm^-1, F（000） = 1704, the final R = 0.0300 and wR = 0.0705 for 2840 observed reflections with I 〉 2σ（I）; and crystal data for 2： monoclinic, space group P21/c with a = 7.929（3）, b = 17.038（5）, c = 11.734（4） A, β = 98.162（6）°, V = 1569.1（9） A^3, C15H16CuN2O5S, Z = 4, Mr = 399.90, Dc = 1.693 g/cm^3, F（000） = 820,μ（MoKα） = 1.554 mm^-1, the final R = 0.0351 and wR = 0.0848 for 2767 observed reflections （I 〉 2σ（I））. The molecular structure of complex 1 consists of one tetra-coordinated Cu（Ⅱ） atom generating a slightly distorted square plane, and a one-dimensional chain structure is formed by intermolecular hydrogen bonds. Complex 2 consists of a diphenolic hydroxyl O-bridged binuclear copper（Ⅱ） structure. The crystal structures of complexes 1 and 2 reveal that the coordinate copper centers are bound to both nitrogen and oxygen atom donors. The usual N,O-trans arrangement of ligands is observed in both cases.

Triboluminescent Complexes of Rare Earth Ⅱ.Mixed-ligand Complexes of Eu^(3+) with Thenoyltrifluoroacetone and Pyridine-N-Oxide or its Substitutive Derivatives

Five triboluminescent mixed-ligand complexes of Eu^(3+)with thenoyltrifluoroacetone(TTA)and pyridine-N-oxide or its substitutive derivatives have been prepared.They are all pale yellow crystalline com- pounds with the formula of Eu(TTA)_3·L(L=py NO.2-pie NO,3-pie NO,4-pic NO,bipy N_2O_2).Their physico-chemical properties have been studied with conductometry,UV and IR absorption and fluorescence spectroscopy.Once the complexes are touched or rubbed by a glass rod,they emit strong red triboluminescent light which is similar to the characteristic fluorescence of Eu^(3+).

Copper complexes of anthrahydrazone bearing pyridyl side chain:Synthesis,crystal structure,anticancer activity,and DNA binding

To expand the study on the structures and biological activities of the anthracyclines anticancer drugs and reduce their toxic side effects,the new anthraquinone derivatives,9‑pyridylanthrahydrazone(9‑PAH)and 9,10‑bispyridylanthrahydrazone(9,10‑PAH)were designed and synthesized.Utilizing 9‑PAH and 9,10‑PAH as promising anticancer ligands,their respective copper complexes,namely[Cu(L1)Cl_(2)]Cl(1)and{[Cu_(4)(μ_(2)‑Cl)_(3)Cl_(4)(9,10‑PAH)_(2)(DMSO)_(2)]Cl_(2)}_(n)(2),were subsequently synthesized,where the new ligand L1 is formed by coupling two 9‑PAH ligands in the coordination reaction.The chemical and crystal structures of 1 and 2 were elucidated by IR,MS,elemental analysis,and single‑crystal X‑ray diffraction.Complex 1 forms a mononuclear structure.L1 coordinates with Cu through its three N atoms,together with two Cl atoms,to form a five‑coordinated square pyramidal geometry.Complex 2 constitutes a polymeric structure,wherein each structural unit centrosymmetrically encompasses two five‑coordinated binuclear copper complexes(Cu1,Cu2)of 9,10‑PAH,with similar square pyramidal geometry.A chlorine atom(Cl_(2)),located at the symmetry center,bridges Cu1 and Cu1A to connect the two binuclear copper structures.Meanwhile,the two five‑coordinated Cu2 atoms symmetrically bridge the adjacent structural units via one coordinated Cl atom,respectively,thus forming a 1D chain‑like polymeric structure.In vitro anticancer activity assessments revealed that 1 and 2 showed significant cytotoxicity even higher than cisplatin.Specifically,the IC_(50)values of 2 against HeLa‑229 and SK‑OV‑3 cancer cell lines were determined to be(5.92±0.32)μmol·L^(-1)and(6.48±0.39)μmol·L^(-1),respectively.2 could also block the proliferation of HeLa‑229 cells in S phase and significantly induce cell apoptosis.In addition,fluorescence quenching competition experiments suggested that 2 might interact with DNA by an intercalative binding mode,offering insights into its underlying anticancer mechanism.CCDC:2388918,1;2388919,2.

Mixed-Ligand Ni(Ⅱ), Co(Ⅱ) and Fe(Ⅱ) Complexes as Catalysts for Esterification of Biomass-Derived Levulinic Acid with Polyol and in Situ Reduction via Hydrogenation with NaBH_(4)

Synthesizing polyol-based ester from biomass feedstocks for the preparation of biolubricant overcomes the dependence on petroleum oil usage.Albeit biomass-derived bio-oil is an alternative for the production of polyol ester,upgrading is essential prior to use as biolubricant.Levulinic acid(LA),obtained from bio-oil was applied for the catalytic esterification with two polyols,e.g.,trimethylolpropane(TMP)and pentaerythritol(PE),in the presence of mixed-ligand Ni(Ⅱ),Co(Ⅱ),and Fe(Ⅱ)complexes as catalyst.New mixed-ligand coordination complexes with empirical formula;[Ni(Phe)(Bpy)Cl].H2O,[Co(Phe)(Bpy)Cl].H2O,and[Fe(Phe)(Tyr)Cl].H2O were synthesized by the reaction of ligands[L-phenylalanine(Phe),4,4'-bipyridine(Bpy),and L-tyrosine(Tyr)]with metal chloride salts and characterized by elemental analysis,magnetic susceptibility,FTIR,TGA/DTA,powder-XRD,and SEM techniques.This study aims to investigate the catalytic activities of the complexes via esterification reaction of levulinic acid with trimethylolpropane and pentaerythritol.In addition,these catalysts were further employed for the in situ hydrogenation of levulinate esters via NaBH_(4) at room temperature upon refluxing.Indeed,the iron(Ⅱ)complex was more potential,exhibiting its efficiency as a homogeneous catalyst for esterification-hydrogenation reaction for synthesizing ester-based oils.

Intramolecular stacking interaction in mixed-ligand complexes containing ATP4-and aromatic N-heterocyclic ligands

The stability constants of the binary ML2+ and ternary M(ATP)L2? complexes, where L=Iq (isoquinoline) or BIm (benzimidazole) and M=Zn2+ or Cd2+, have been determined by potentiometric pH titration in aqueous solution at I=0.1 mol/L (NaClO4), T=25°C. The stability of the ternary complexes characterized by ΔlogKM=logKM(ATP)LM(ATP)L- logKMML corresponding to the equilibrium M(ATP)2? + ML2+ = M(ATP)L2? + M2+ in higher than what would be expected on statistical grounds. The increase may be related to the stacking interaction between the aromatic ring of the ligands L and the purine moiety of ATP4–. 1H NMR studies of Zn2+/ATP4?/L confirm the presence of stacking in the ternary complexes. It is concluded that the strength of the intramolecular stacking interaction ia dependent on the structure of the aromatic ring of the ligand L and the formation of a metal ion bridge. Possible implications an discussed briefly.

Synthesis and Crystal Structure of a Mixed-ligand Manganese(Ⅱ) Complex Containing Abundant Hydrogen-bonding Interactions

A new mixed-ligand Mn（II）complex,namely [Mn（bipy）2（Huca）]·5H2O（1,bipy = 2,2＇-bipyridine,and H3uca = uracil-5-carboxylic acid）has been prepared and characterized by single-crystal X-ray diffraction,FT-IR spectroscopy and thermogravimetric analysis.It crystallizes in monoclinic,space group C2/c with a = 23.597（8）,b = 16.434（5）,c = 15.531（6）,β = 112.785（6）o,C25H28MnN6O9,Mr = 611.47,V = 5553（3）3,Z = 8,μ = 0.538,Dc = 1.463 g/cm3,F（000）= 2536,R = 0.0441 and wR = 0.1230 for all 5227 observed reflections（I 2σ（I））.The manganese（II）center is surrounded by three bidentate chelating ligands,and it displays a severely distorted octahedral geometry,with cis angles ranging from 72.14（6）to 109.78（6）o.Extensive intermolecular hydrogen bonds link the [Mn（bipy）2（Huca）] monomers and lattice water molecules to yield a three-dimensional supramolecular framework.TGA shows complete removal of all lattice water molecules above 270 ℃.

Structure and Luminescent Property of a Tetrahedral Silver(Ⅰ) Cluster Complex Based on Phosphor and Sulphur Mixed-ligand System

A tetrahedral silver(I) cluster complex {Ag4[HC(PPh2)3](S2PPh2)3}ClO4(1,HC(PPh2)3 = 1,1,1-tris(triphenylphosphino)methane, S2PPh2 = diphenyldithiophosphinate) was synthesized by assembling silver ion with phosphor and sulphur mixed-ligand system. The complex was characterized by single-crystal X-ray crystallography, high-resolution mass spectroscopy and thermal analysis. In the crystal structure, an inverted tetrahedron was constructed from Ag4 metal skeleton. The Ag4 cage was stabilized by three diphenyldithiophosphinate ligands and one 1,1,1-tris(triphenylphosphino)methane ligand. 1 exhibits luminescent properties in solid state. A bright yellow-green emission centered at 533 nm has been observed in solid state. Large Stokes' shifts with long range of emissive lifetime indicate that the emission likely originates from a triplet state parentage.

Synthesis and Spectral Properties of Mixed-Ligand Complexes of Lanthanide Perchlorate with Bis-(phenylsulfinyl)ethane and Organic Lewis Bases

Six lanthanide complexes with bis(phenylsulfinyl)ethane(bphse) and organic bases(phen: 1,10 phenanthroline and bipy: 2,2'-bipyridine) were synthesized and characterized by elemental analysis, conductance and spectral (IR, UV Visible) data. The complexes were Ln(bphse) 2(bipy)(ClO 4) 3· n H 2O and Ln 2(bphse) 3(phen) 2(ClO 4) 6·H 2O(where Ln=Nd, Eu and Gd; n =0～2). IR spectral data confirmed that the lanthanide ions were coordinated by oxygen atoms from bphse and nitrogen atoms from phen or bipy. Exitation and emission spectra of Eu complexes were measured and discussed.

Coordination behavior of N-benzoylamino acids: Synthesis and structure of mixed-ligand complexes of palladium(Ⅱ) with N-benzoylamino acid dianion and diamine

Four new mixed-ligand complexes of pailadiumt(Ⅱ) with L1(N-benzoyl-α-amino acid dianion) and L2[ethyldiamine (en),2,2’-bipyridine (Bpy) and 1,10-phenanthroline (Phen)] were synthesized.Ail the complexes have been characterized by elemental analyses,molar conductance,infrared and 1H NMR spectra and therme-gravimetric analyses.Crystal structures of [Pd(Bpy)(Bzval-N,O)] and [Pd(en) (Bzphe-N,O)] H2O have been do termmed by X-ray diffraction analysis.The results indicate that in all the complexes hgand L1 coordinates to palladium (Ⅱ) through deprotonated amide nitrogen and carboxylic oxygen,and there are some intramolecular nonrovalent in teractions in the complexes.

Synthesis and Properties of a One-Dimensional Mixed-Ligand Cd(Ⅱ) Complex with Helical Structure

The title complex, [ [ Cd（Him） （OH-BDC） （H2O）2 ]· 3H2O]n （ 1 ） （Him is imidazole, OH-H2BDC is 5-hydroxyisophthalic acid）, was synthesized by liquid/liquid diffusion method at room temperature. The complex crystallizes in orthorhombic, space group P212121, with a = 0.671 6 （7）, b = 1.380 6 （2）, c = 1.7421（2） nm, V = 1.615 2（3） nm3, C11H18CdN2O10, Mr = 450.67, Dc = 1.853 g/cm3, μ = 1.407 mm^-1, F（000） = 904, Z = 4, the final R1 = 0.020 9 and wR2 = 0.045 3 for 3 211 observed reflections （Ⅰ 〉 2σ （Ⅰ））. In the structure of 1, the OH-BDC ligands exhibiting bis-bidentate coordination mode bridge the adjacent Cd centers to form a one-dimensional helical chain and the second ligand Him acting as terminal ligands are attached to the helical chain. It is notable that a series of complicated hydrogen bonds （e. g., N-H… O, O-H… O） exist in the structure, which link neighboring helices into a three-dimensional supramolecular architeeture. An observed intense blue luminescence with an emission band peaking at 390 nm for 1 may be resulted from ligand-to-metal charge transfer （LMCT）.

Synthesis, Characterization and Antimicrobial Screening Mixed-Ligand Cu(II) and Zn(II) Complexes;DNA Binding Studies on Cu(II) Complex

Several mixed ligand Cu(II), Zn(II) complexes using (benzylidenethiourea) (obtained by the condensation of benzaldehyde and thiourea) as the primary ligand and (acetamide or thioacetamide) as an additional ligand were synthesized and characterized analytically and spectroscopically, magnetic susceptibility and molar conductance measurements ,as well as by UV-Vis. and IR spectroscopy. The interaction of the complexes with calf thymus (CT)DNA was studied using absorption spectra, while the concentration of DNA in gel electrophoresis remained constant at 10 μl. They exhibit absorption hypochromicity increased during the binding of the complexes to calf thymus DNA. The complexes show enhanced antimicrobial activities complexes with the free ligand. A theoretical treatment of the formation of complexes in the gas phase was studied, this was done using the HYPERCHEM-6 program for the Molecular mechanics and Semi-empirical calculations.

Cleavage of DNA by a New Mixed-ligand Cu(Ⅱ) Complex

Cleavage of DNA pUC19 by [Cu(saldien)(NH3)]Cl2 (here, saldien=bis(salicylicdene)- diethylenetriamine) was investigated at different pHs, times, concentrations, and 37℃. It was found that the copper(Ⅱ) complex could cleave DNA without added coreactants.

Discovery of nano organo-clay complex pore-fractures in shale and its scientific significance:A case study of Cretaceous Qingshankou Formation shale,Songliao Basin,NE China

A new pore type,nano-scale organo-clay complex pore-fracture was first discovered based on argon ion polishing-field emission scanning electron microscopy,energy dispersive spectroscopy and three-dimensional reconstruction by focused ion-scanning electron in combination with analysis of TOC,R_(o)values,X-ray diffraction etc.in the Cretaceous Qingshankou Formation shale in the Songliao Basin,NE China.Such pore characteristics and evolution study show that:(1)Organo-clay complex pore-fractures are developed in the shale matrix and in the form of spongy and reticular aggregates.Different from circular or oval organic pores discovered in other shales,a single organo-clay complex pore is square,rectangular,rhombic or slaty,with the pore diameter generally less than 200 nm.(2)With thermal maturity increasing,the elements(C,Si,Al,O,Mg,Fe,etc.)in organo-clay complex change accordingly,showing that organic matter shrinkage due to hydrocarbon generation and clay mineral transformation both affect organo-clay complex pore-fracture formation.(3)At high thermal maturity,the Qingshankou Formation shale is dominated by nano-scale organo-clay complex pore-fractures with the percentage reaching more than 70%of total pore space.The spatial connectivity of organo-clay complex pore-fractures is significantly better than that of organic pores.It is suggested that organo-complex pore-fractures are the main pore space of laminar shale at high thermal maturity and are the main oil and gas accumulation space in the core area of continental shale oil.The discovery of nano-scale organo-clay complex pore-fractures changes the conventional view that inorganic pores are the main reservoir space and has scientific significance for the study of shale oil formation and accumulation laws.

Saturation Estimation with Complex Electrical Conductivity for Hydrate-Bearing Clayey Sediments:An Experimental Study

Clays have considerable influence on the electrical properties of hydrate-bearing sediments.It is desirable to understand the electrical properties of hydrate-bearing clayey sediments and to build hydrate saturation(S_(h))models for reservoir evaluation and monitoring.The electrical properties of tetrahydrofuran-hydrate-bearing sediments with montmorillonite are characterized by complex conductivity at frequencies from 0.01 Hz to 1 kHz.The effects of clay and Sh on the complex conductivity were analyzed.A decrease and increase in electrical conductance result from the clay-swelling-induced blockage and ion migration in the electrical double layer(EDL),respectively.The quadrature conductivity increases with the clay content up to 10%because of the increased surface site density of counterions in EDL.Both the in-phase conductivity and quadrature conductivity decrease consistently with increasing Sh from 0.50 to 0.90.Three sets of models for Sh evaluation were developed.The model based on the Simandoux equation outperforms Archie’s formula,with a root-mean-square error(E_(RMS))of 1.8%and 3.9%,respectively,highlighting the clay effects on the in-phase conductivity.The fre-quency effect correlations based on in-phase and quadrature conductivities exhibit inferior performance(E_(RMS)=11.6%and 13.2%,re-spectively)due to the challenge of choosing an appropriate pair of frequencies and intrinsic uncertainties from two measurements.The second-order Cole-Cole formula can be used to fit the complex-conductivity spectra.One pair of inverted Cole-Cole parameters,i.e.,characteristic time and chargeability,is employed to predict S_(h) with an E_(RMS) of 5.05%and 9.05%,respectively.

Tuberous sclerosis complex combined with primary lymphedema:A case report

BACKGROUND Tuberous sclerosis complex(TSC)and primary lymphedema(PLE)are both rare diseases,and it is even rarer for both to occur in the same patient.In this work,we have provided a detailed description of a patient's clinical presentation,imaging findings,and treatment.And a retrospective analysis was conducted on 14 published relevant case reports.CASE SUMMARY A 16-year-old male came to our hospital for treatment due to right lower limb swelling.This swelling is already present from birth.The patient’s memory had been progressively declining.Seizures had occurred 1 year prior at an unknown frequency.The patient was diagnosed with TSC combined with PLE through multimodal imaging examination:Computed tomography,magnetic resonance imaging,and lymphoscintigraphy.The patient underwent liposuction.The swelling of the patient's right lower limb significantly improved after surgery.Epilepsy did not occur.after taking antiepileptic drugs and sirolimus.CONCLUSION TSC with PLE is a rare and systemic disease.Imaging can detect lesions of this disease,which are important for diagnosis and treatment.

SYNTHESIS AND STRUCTURE OF A MIXED-LIGANDS COMPLEX [CU(R-LACT)(O-PHEN)(H_2O)]·4H_2O

A mixed-ligands complex with the formula of [Cu(R-lact)(o-phen)(H2O)]·4H2O was synthesized by the reaction of copper carbonate with racemic lactic acid(RS-H2lact), and then with o-phenanthroline(o-phen) in ethanol-water(95%) solution. One of the two obtained compounds was dark blue column single crystal and was characterized by elemental analysis, IR spectrum and X-ray single crystal diffraction. The crystal belongs to triclinic system with space group P1, a=7.2825(5), b=11.7322(8), c=12.1194(8), α=65.8280(10)°, β=84.2120(10)°,γ=75.3290(10)°, V=913.88(11)3, Z=2, Dc=1533kg·m-3, Mr=421.89, μ(Mo K\α)=1.240mm-1,λ =0.71073, the final R =0.0483 and ωR =0.1199 [I>2σ(I)] for 3120 observed reflections,F(000)=438. The copper atom is five coordinated with the distorted square pyramid environment.The five coordinated atoms are two oxygen atoms of depronated hydroxyl group and carboxyl of H2 lact, two nitrogen atom of o-phen and one oxygen atom of water molecule.

Modeling time-dependent mechanical behavior of hard rock considering excavation-induced damage and complex 3D stress states

To investigate the long-term stability of deep rocks,a three-dimensional(3D)time-dependent model that accounts for excavation-induced damage and complex stress state is developed.This model comprises three main components:a 3D viscoplastic isotropic constitutive relation that considers excavation damage and complex stress state,a quantitative relationship between critical irreversible deformation and complex stress state,and evolution characteristics of strength parameters.The proposed model is implemented in a self-developed numerical code,i.e.CASRock.The reliability of the model is validated through experiments.It is indicated that the time-dependent fracturing potential index(xTFPI)at a given time during the attenuation creep stage shows a negative correlation with the extent of excavationinduced damage.The time-dependent fracturing process of rock demonstrates a distinct interval effect of the intermediate principal stress,thereby highlighting the 3D stress-dependent characteristic of the model.Finally,the influence of excavation-induced damage and intermediate principal stress on the time-dependent fracturing characteristics of the surrounding rocks around the tunnel is discussed.

Clarifying the relationship between PM2.5 and ozone complex pollution and synoptic patterns in a typical petrochemical city in the Bohai Rim region of China:Implications for air pollution forecasting and control

Meteorological conditions are vital to PM_(2.5)and ozone(O_(3))complex pollution.Herein,the T-mode principal com-ponent analysis method was employed to objectively classify the 925-hPa geopotential height field of Dongying from 2017 to 2022.Synoptic patterns associated with four pollution types-namely,PM_(2.5)-only pollution,O_(3)-only pollution,Co-occurring of PM_(2.5)and O_(3)pollution,Non-occurring of PM_(2.5)and O_(3)pollution-were characterized at different time scales.The results indicated that synoptic classes conducive to PM_(2.5)-only pollution were“high-pressure top front”,“offshore high-pressure rear”,and“high-pressure inside”,while those conducive to O_(3)-only pollution were“offshore high-pressure rear”,“subtropical high”,and“high and low systems”.The Co-occurring of PM_(2.5)and O_(3)pollution were influenced by high pressure,and the Non-occurring of PM_(2.5)and O_(3)pollution were linked to precipitation and strong northerly winds.The variation in dominant synoptic patterns is crucial in the frequency changes of the four pollution types,which was further validated through the analysis of typical cases.Under the favorable meteorological conditions of high-pressure control with strong northerly winds or a subtropical high and inverted trough both with strong precipitation,there is potential to achieve coordinated control of PM_(2.5)and O_(3)in Dongying.Additionally,measures like artificially manipulating local humidity could be adopted to alleviate pollution levels.This study reveals the importance of comprehending the meteorological factors contributing to the formation of PM_(2.5)and O_(3)complex pollution for the improvement of urban air quality in the Bohai Rim region of China when emissions are high and the concentration of air pollutants exhibits high meteorological sensitivity.