Removal of manganese from waste water by complexation-ultrafiltration using copolymer of maleic acid and acrylic acid

Copolymer of maleic acid and acrylic acid （PMA-100）, combining with polyvinyl butyral （PVB） ultrafiltration membrane was used for the removal of Mn（II） from waste water by complexation-ultrafiltration. The carboxylic group content of PMA-100 and the rate of complexation reaction were measured. Effects of the mass ratio of PMA-100 to Mn（II） （n）, pH, background electrolyte, etc on the rejection rate （R） and permeate flux （J） were investigated. The results show that carboxylic group content of PMA-100 is 9.5 mmol/g. The complexation of Mn（II） with PMA-100 is rapid and completed within 5 min at pH 6.0. Both R and J increase with pH increasing in the range of 2.5-7.0, and R increases with the increase of n at pH 6.0 while J is little affected. The background electrolyte leads to the decrease of R, and CaCl2 has much greater effect on R than NaCl at the same ionic strength.

Heterointerface Engineering-Induced Oxygen Defects for the Manganese Dissolution Inhibition in Aqueous Zinc Ion Batteries

Manganese-based material is a prospective cathode material for aqueous zinc ion batteries(ZIBs)by virtue of its high theoretical capacity,high operating voltage,and low price.However,the manganese dissolution during the electrochemical reaction causes its electrochemical cycling stability to be undesirable.In this work,heterointerface engineering-induced oxygen defects are introduced into heterostructure MnO_(2)(δa-MnO_(2))by in situ electrochemical activation to inhibit manganese dissolution for aqueous zinc ion batteries.Meanwhile,the heterointerface between the disordered amorphous and the crystalline MnO_(2)ofδa-MnO_(2)is decisive for the formation of oxygen defects.And the experimental results indicate that the manganese dissolution ofδa-MnO_(2)is considerably inhibited during the charge/discharge cycle.Theoretical analysis indicates that the oxygen defect regulates the electronic and band structure and the Mn-O bonding state of the electrode material,thereby promoting electron transport kinetics as well as inhibiting Mn dissolution.Consequently,the capacity ofδa-MnO_(2)does not degrade after 100 cycles at a current density of 0.5 Ag^(-1)and also 91%capacity retention after 500cycles at 1 Ag^(-1).This study provides a promising insight into the development of high-performance manganese-based cathode materials through a facile and low-cost strategy.

Facile synthesis of Cu-doped manganese oxide octahedral molecular sieve for the efficient degradation of sulfamethoxazole via peroxymonosulfate activation

Advanced processes for peroxymonosulfate(PMS)-based oxidation are efficient in eliminating toxic and refractory organic pol-lutants from sewage.The activation of electron-withdrawing HSO_(5)^(-)releases reactive species,including sulfate radical(·SO_(4)^(-)),hydroxyl radical(·OH),superoxide radical(·O_(2)^(-)),and singlet oxygen(1O_(2)),which can induce the degradation of organic contaminants.In this work,we synthesized a variety of M-OMS-2 nanorods(M=Co,Ni,Cu,Fe)by doping Co^(2+),Ni^(2+),Cu^(2+),or Fe^(3+)into manganese oxide oc-tahedral molecular sieve(OMS-2)to efficiently remove sulfamethoxazole(SMX)via PMS activation.The catalytic performance of M-OMS-2 in SMX elimination via PMS activation was assessed.The nanorods obtained in decreasing order of SMX removal rate were Cu-OMS-2(96.40%),Co-OMS-2(88.00%),Ni-OMS-2(87.20%),Fe-OMS-2(35.00%),and OMS-2(33.50%).Then,the kinetics and struc-ture-activity relationship of the M-OMS-2 nanorods during the elimination of SMX were investigated.The feasible mechanism underly-ing SMX degradation by the Cu-OMS-2/PMS system was further investigated with a quenching experiment,high-resolution mass spec-troscopy,and electron paramagnetic resonance.Results showed that SMX degradation efficiency was enhanced in seawater and tap water,demonstrating the potential application of Cu-OMS-2/PMS system in sewage treatment.

Covalency competition induced selective bond breakage and surface reconstruction in manganese cobaltite towards enhanced electrochemical charge storage

Manganese cobaltite(MnCo_(2)_(4))is a promising electrode material because of its attractive redox chemistry and excellent charge storage capability.Our previous work demonstrated that the octahedrally-coordinated Mn are prone to react with the hydroxyl ions in alkaline electrolyte upon electrochemical cycling and separates on the surface of spinel to reconstruct into d-MnO_(2) nanosheets irreversibly,thus results in a change of the reaction mechanism with Kþion intercalation.However,the low capacity has greatly limited its practical application.Herein,we found that the tetrahedrally-coordinated Co_(2) þions were leached when MnCo_(2)_(4) was equilibrated in 1 mol L^(-1) HCl solution,leading to the formation of layered CoOOH on MnCo_(2)_(4) surface which is originated from the covalency competition induced selective breakage of the CoT–O bond in CoT–O–CoO and subsequent rearrangement of free Co_(6) octahedra.The as-formed CoOOH is stable upon cycling in alkaline electrolyte,exhibits conversion reaction mechanism with facile proton diffusion and is free of massive structural evolution,thus enables utilization of the bulk electrode material and realizes enhanced specific capacity as well as facilitated charge transfer and ion diffusion.In general,our work not only offers a feasible approach to deliberate modification of MnCo_(2)_(4)'s surface structure,but also provides an in-depth understanding of its charge storage mechanism,which enables rational design of the spinel oxides with promising charge storage properties.

Structure and Magnetic Properties of a Manganese Complex with 1-Carboxymethylpyridinium-3-carboxylate

One complex with a zwitterionic dicarboxylate ligand, [Mn（L）（N3）]n 1 （L = 1-car- boxymethylpyridinium-3-carboxylate）, was synthesized and structurally characterized. Complex 1 crystallizes in triclinic, space group P1 with a = 7.570（2）, b = 7.808（2）, c = 9.232（3） A, β= 94.450（19）°, V= 489.0（3） A3, Z = 2, Mr = 277.11, Dc = 1.882 g/cm3, F（000） = 278,μ = 1.359 mm-1, S = 1.021, the final R = 0.0509 and wR = 0.1149 for 2236 observed reflections with 1 〉 2σ（I）. Complex 1 consists of two-dimensional coordination layers in which the anionic uniform chains with mixed triple bridges （one end-on （EO） azide and two syn-syn carboxylates） are cross-linked by the flexible cationic N-methylpyridinium spacers. Magnetic studies demonstrated that the triple bridge in 1 transmits antiferromagnetic coupling between the Mn（Ⅱ） ions.

Synthesis, Crystal Structure and Theoretical Calculation of a Novel 2D Network of Manganese(Ⅱ) Complex

A novel complex, [Mn（2-NCP）（H2BTC）（H2O）]n（1, 1,3,5-H3BTC = 1,3,5-benzenetricarboxylic acid, 2-HNCP = 2-（2-carboxyphenyl）-1 H-imidazo（4,5-f）-（1,10）phenanthroline）, was hydrothermally synthesized and structurally characterized by elemental analysis, IR, XRD and single-crystal X-ray diffraction. Structural analyses reveal that complex 1 exhibits a（6, 6）-connected topology network with a Schl?fli symbol of（63）. The adjacent 2 D layers are further stacked via strong hydrogen-bonding interactions, giving a 3 D supramolecular framework. In addition, the structure of complex 1 was calculated by the B3LYP/LANL2 DZ method by Gaussian program. The results from natural bond orbital（NBO） analysis shows obvious covalent interaction between the coordinated atoms and Mn（Ⅱ） ion.

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 ℃.

Hydrothermal Synthesis and Crystal Structure of a New Manganese(II) Complex with 2,4-Pyridine-dicarboxylic Acid and 2,2′-Bipyridine Ligands

A new metal-organic complex [Mn2（PDC）2（bipy）2（H2O）2] （H2PDC = 2,4-pyridine-dicarboxylic acid, bipy = 2,2′-bipyridine） 1 has been hydrothermally synthesized and structurally characterized by elemental analysis, IR spectrum, TG and single-crystal X-ray diffraction. The compound crystallizes in triclinic, space group P ^-1 with a = 7.376（3）, b = 9.990（4）, c = 11.950（5） A^°, α= 75.217（5）, β = 78.052（5）, γ = 70.655（5）°, V = 796.0（5）A^°3, C34HE6Mn2N6O10, Mr = 788.49, De = 1.645 g/cm^3,μ（MoKa） = 0.866 mm^-1, F（000） = 235, Z = 1, the final R = 0.0425 and wR = 0.0700 for 1971 observed reflections （I 〉 2σ（I））. In the crystal structure, the manganese atom is six-coordinated by two carboxylate oxygen atoms from two different PDC ligands, one aqua ligand, and three nitrogen atoms from 2,2′-bipy and PDC ligands, giving a distorted octahedral geometry. It exhibits a three-dimensional supramolecular network defined by O-H…O hydrogen-bonding interactions.

Hydrothermal Synthesis and Crystal Structure of a Manganese(Ⅱ) Complex:Mn_(1.5)(cbba)_3(phen)

A new metal-organic complex Mn1.5（cbba）3（phen）（Hcbba = 2-（4＇-chlorine-ben-zoyl）benzoic acid,phen = 1,10-phenanthroline） 1 has been hydrothermally synthesized and struc-turally characterized by single-crystal X-ray diffraction,elemental analyses,TG and IR spectro-scopy.The compound crystallizes in triclinic,space group P1 with a = 12.137（2）,b = 14.535（3）,c = 14.894（3）,α = 86.380（3）,β = 70.381（3）,γ = 72.647（3）°,V = 2360.3（8）3,C107H64Cl6Mn3N4O18,Mr = 2071.14,Dc = 1.457 g/cm3,μ（MoKα） = 0.638 mm-1,F（000） = 1055,Z = 1,the final R = 0.0638 and wR = 0.1905 for 6155 observed reflections（I 2σ（I））.It exhibits a 3D supramolecular network through hydrogen bonding and π-π stacking interactions.

Synthesis, Crystal Structure, Fluorescence, Thermal Stability and Magnetic Properties of the Dinuclear Manganese(Ⅱ) Complex [Mn_2(L)_2(2,2'-bipy)_2(H_2O)_5]_2·3H_2O

A new dinuclear manganese complex [Mn2（L）2（2,2＇-bipy）2（H2O）512·3H2O has been synthesized with MnSO4·H2O, 2,2＇-bibenzoic acid （H2L） and 2,2＇-bipyridine（2,2＇-bipy） in the mixed solvent ethanol and water. It crystallizes in monoclinic, space group Pi with a = 9.9944（10）, b = 21.939（2）, c = 25.628（3） A, a = 108.429（3）, β = 100.613（4）, 7 = 102.821（3）°, V = 4997.9（9） A3, Dc= 1.355 g/cm^3, Z = 2, F（000） = 2108, GOOF = 1.074, the R= 0.0626 and wR= 0.1531. The structure of the complex contains two [Mn2（L）2（2,2＇-bipy）2] units, ten coordinated H2O molecules and three uncoordinated H2O molecules. The fluorescence, thermal stability and magnetic properties of the complex were investigated.

Synthesis, Structure and Catalytic Activity of a Manganese(Ⅲ) Complex Based on 2-(2-Hydroxyphenyl)-5,6-dichlorobenzimidazole Ligands

A new ligand, 2-（2-hydroxyphenyl）-5,6-dichlorobenzimidazole, H2pbmCl2（1）, and a novel MnIII complex, [MnIII（HpbmCl2）（pbmCl2）（DMF）2]（2）,（DMF = N,N-dimethylformamide）, have been synthesized and characterized. The crystal of compound 1（C13H8Cl2N2O, Mr = 279.12） belongs to the monoclinic system, space group P21 with a = 3.770（5）, b = 25.20（3）, c = 5.865（7） A, = 92.727（17）o, V = 556.6（12） A3, Z = 2, Dc = 1.665 g/cm^3, S = 1.137, μ= 0.568 mm^-1, F（000） = 284, the final R = 0.0876 and wR = 0.2334 for 1848 independent reflections. The molecule is planar due to the presence of a strong intramolecular hydrogen bond between O–H group of phenol and N atom of imidazole. H2pbmCl2（1） molecules are arranged into a one-dimensional linear chain through intermolecular hydrogen bonds（N–H…O and C–H…Cl）. The crystal of complex 2（C32H27Cl4MnN6O4, Mr = 756.34） belongs to the monoclinic system, space group P21/c with a = 19.043（10）, b = 10.808（5）, c = 18.704（11）A, β= 115.540（6）°, V = 3473（3） A3, Z = 4, Dc = 1.446 g/cm^3, S = 1.3, μ = 0.733 mm-1, F（000） = 1544, the final R = 0.1219 and wR = 0.2681 for 7811 independent reflections. The Mn ion adopts a distorted octahedral geometry coordinated by two deprotonated H2pbmCl2 ligands and two DMF molecules. The [MnIII（HpbmCl2）（pbmCl2）（DMF）2] molecules are arranged into a three-dimensional structure through hydrogen bonds（N–H…N, C–H…N and C–H…Cl） and weak π···πinteractions. The activity measurements suggest that complex 2 is able to serve as a catalyst for H2O2 disproportionation reaction to form O2 in neutral water solution.

Molecular and Supramolecular Structures of Manganese(Ⅱ) and Cobalt(Ⅱ) Complexes with 1-Carboxymethylpyridinium-4-carboxylate

Two complexes with a zwitterionic dicarboxylate ligand,Mn（L）2（H2O）4 1 and Co（L）2（H2O）4 2（L = 1-carboxymethylpyridinium-4-carboxylate）,were synthesized and structurally characterized.Complex 1 crystallizes in monoclinic,space group P21 with a = 6.490（2）,b = 19.210（7）,c = 7.813（3） ,β = 92.716（5）o,V = 972.9（6） 3,Z = 2,Mr = 487.28,Dc = 1.663 g/cm3,F（000） = 502,μ = 0.749 mm-1,S = 1.060,the final R = 0.0377 and wR = 0.0893 for 3292 observed reflections with I 2σ（I）.Complex 2 is isomorphous with 1,with a = 6.478（2）,b = 19.052（7）,c = 7.742（3） ,β = 92.690（4）o,V = 954.6（6） 3,Z = 2,Mr = 491.28,Dc = 1.709 g/cm3,F（000） = 506,μ = 0.971 mm-1,S = 1.035,the final R = 0.0425 and wR = 0.0809 for 3289 observed reflections with I 2σ（I）.In the compounds,the mononuclear [M（L）2（H2O）4] units with trans-octahedral coordination geometry are linked into 3D architectures via hydrogen bonding（or second-sphere coordination） involving carboxylate groups and coordinated water molecules.The 3D networks illustrate a 3,8-connected net with Schlfli symbol（4·62）2（42·623·83）.

Hydrothermal Syntheses and Crystal Structures of Two Complexes of Cobalt and Manganese Assembled by 4,4'-Oxydibenzoic Acid

Two new coordination polymers [Co（oba）（mbix）]2n·nH2O （1） and [Mn（Hoba）2（H2O）2]n （2） （H2oba = 4,4＇-oxydibenzoic acid, mbix = 1,3-bis（imidazol-1-ylmethyl）benzene） have been successfully synthesized under hydrothermal conditions. Their structures have been determined by elemental analyses, IR spectroscopy, UV and single-crystal X-ray diffraction analysis. The intermolecular hydrogen bonding and π-π stacking interactions extend the complexes into a 3D supramolecular structure.

Synthesis and Crystal Structure of a Spiral-chain Manganese(Ⅲ) Complex Containing Azide Bridge,[Mn(bzan)N_3]_n

The title complex, C22H22MnN5O2, crystallizes in orthorhombic system, space group P212121 with a = 6.887(1), b = 11.718(2), c = 25.721(5) ? V = 2075.7(7) 3, Z = 4, Mr = 443.39, F(000) = 920, Dc = 1.419 g/cm3 and m = 0.665mm-1 (MoKa). The structure was refined to R = 0.0593 and wR = 0.1427 for 3576 observed reflections with I ≥ 2s(I). The Mn(Ⅲ) atom is coordinated to one bzan2- [bzan2- = N, N-ethylenebis(benzoylacetoneiminato)] ligand binding in the equatorial mode and two N3- ions in the axial positions. The azide acts as a trans--(1, 3) bridge, resulting in an infinite helical chain propagating along the b axis.

Synthesis and Crystal Structure of a New Dinuclear Manganese(Ⅱ) Manganese(Ⅲ) Complex of a Macrocyclic Ligand

A mixed-valence dinuclear manganese complex, [Mn ⅡMn ⅢL](ClO 4)·1/2MeOH, where L is a macrocyclic ligand derived from the cyclocondensation of sodium 2,6-diformyl-4-methylphenolate with N,N-bis(2-aminoethyl)-2-hydroxybenzyl amine, was obtained and its structure was determined by X-ray diffraction. The orange crystal is a monoclinic system with space group P2 1/c and lattice parameters a=1.1617(4), b=1.4005(3), c=1.4641(3) nm, β=113.03(2)°, and Z=2. The crystal structure shows that each pendant-arm is bonded in a bidentate fashion to the adjacent metal atom and that both the arms are on the same side of the macrocycle. The two Mn atoms are bridged by two μ 2-phenoxy oxygen atoms of the tetra-imine macrocycle, and each Mn atom, locating in a trigonal prismatic coordination environment(N 3O 3), is six-coordinated by the two imine nitrogen atoms, one tertiary nitrogen atom and a pendant phenol moiety apart from the two oxygen atoms.

Crystal Structure of Binuclear Manganese(Ⅲ) Complex with Schiff-base Ligand,〔Mn_2(C_(22)H_(22)N_2O_2)_2(EtOH)_2 (bipy)〕(ClO_4)_2

The title complex, [Mn2L2(EtOH)2 (bipy )](ClO4)2 (L=N,N'-ethylenebis (1-phenyl-3-imino-1-butanonato), bipy = 4, 4'-bipyridine] crystallizes inmonoclinic system, space group P21/c with a= 12. 63O(5), b=13- 151 (2), c=18. 3773001 reflections The two [MnL(EtOH)]+ units are joined by one 4, 4'-bipyridine molecule to form a centrosymmetric binuclear complex cation [Mn2L2(EtOH)2 (bipy]2+. The coordination geometry around Mn atoms is a distorted octahe-dron with equatorial plane N2O2 from the Schiff base ligand L.

Control of the Electronic Structure of Manganese Nitrido Complexes by Para Ring Substituents：a Theoretical Study

The relationship between the electronic structures of manganese nitrido complexes and the substituted ligands is investigated by using density functional theory.By designing a series of manganese nitrido complexes [Mn（SalenR）N]＋ with different para ring substituents（R = H,CH_3,NH_2,OCH_3,NMeF,etc） of the ancillary ligand,the properties of manganese-nitrogen bonds were compared for two kinds of electronic structures,of which the radical resides on metal center or the coordinated ring ligand.Our calculation shows that for R = H,CH_3 and NH_2,the [Mn（SalenR）N]＋ complexes have a high-valent Mn（VI） center,and for R = OCH_3 and NMeF,the complexes represent a configuration where the radical delocalizes on the ligand.It is found that the relative energies of these two species depend on electronic properties of the substituent,originating from the intrinsic property of HOMO-LUMO gaps.

Preservation Effect of Prochloraz-manganese Chloride Complex on Postharvest ‘Shatangju'( Citrus reticulata)Fruits

[ Objective ] The paper was to solve the weakness of heavy postharvest diseases and non-endurable storage of ＇ Shatangju＇, to improve the preservation effect of ＇ Shatangju＇. [ Method ] Fruits were dipped in different concentrations of procbloraz-manganesc chloride complex solutions. The postharvest weight loss rate, soluble solids content and decay rate of fruits were determined, and the safety of chemical agents was observed and evaluated. [ Result ] Prochloraz-manganese chloride complex had significant preservation effect on postharvest ＇ Shatangju＇ fruits, and the appropriate concentration was 0.15% -0.20% （effective content） ; the decay rates of fruits stored at room temperature for 15, 30, 45, 60 and 90 d were 0, 5%, 〈 10%, 〈 10% and 〈 30% ; there was no specific changes in smell and flavor of non-decayed fruits. [ Conclusion ] Prochloraz-manganese chloride complex solution had significant preservation effect on ＇ Shatangju＇ by inhibiting and reducing the growth and development of pathogenic bacteria, and the effect was much better under refrigeration condition.

Synthesis and Characterization of a Homochrial Manganese(Ⅱ)Complex Constructed from (1R,2R)-(-)-Diaminocyclohexane-N,N biscarboxyl-salicylidene)

A homochrial manganese（Ⅱ） complex derived from chiral salen ligand （1R,2R）-（-）diaminocyclohexane-N,N-biscarboxyl-salicylidene） （1） has been synthesized through solvothermal procedure and characterized by IR,elemental analysis,TGA,circular dichroism （CD）,powder and single-crystal X-ray crystallography.It crystallizes in monoclinic,space group C2 with a=32.987（7）,b=7.4662（15）,c=17.931（4）,β=97.82（3）°,V=4375.0（15） 3,Z=8,D c=1.544 g/cm 3,F（000）=2096,M r=508.36,μ=0.658 mm-1,the final GOOF=0.975,R=0.0676 and wR=0.2068 for 6357 observed reflections with I 2σ（Ⅰ）.The coordination polymer 1 possesses a 1D infinite zigzag chain architecture constructed by the dicarboxyl-functionalized metallosalen ligand （MnSalen）,and the polymeric chains are further assembled into a 2D supramolecular network structure via strong intermolecular hydrogen bonding interactions between the adjacent zigzag chains.

Synthesis and Crystal Structure of a Manganese(Ⅱ) Complex with 2-(4′-Chlorine-benzoyl)-benzoic Acid and 1,10-Phenanthroline

A new metal-organic complex Mn2（cbba）4（phen）2 （Hcbba = 2-（4＇-chlorine-benzoyl）- benzoic acid, phen = 1,10-phenanthroline） 1 has been hydrotherrnally synthesized and structurally characterized by single-crystal X-ray diffraction, elemental analyses and IR spectroscopy. The compound crystallizes in orthorhombic, space group Pbcn with α = 12.154（5）, b = 18.166（7）, c = 31.197（13） A, V = 6887（5） A^3, C80H48Cl4Mn2N4O12, Mr= 1508.90, Dc = 1.455 g/cm^3, μ（MoKα） = 0.591 mm^-1, F（000） = 3080, Z = 4, the final R = 0.0408 and wR = 0.0873 for 4033 observed reflections （I 〉 2σ（I））. In the crystal structure, the manganese atom is six-coordinated with four carboxylate oxygen atoms from three different cbba ligands and two nitrogen atoms from phen ligands, showing a distorted octahedral geometry. Furthermore, it exhibits a 3D supramolecular network through π-π interactions.