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 and Crystal Structure of a Mixed-Valence Trinuclear Manganese Complex: Mn_3O(O_2CPh)_6(Py)_3

A new mixed-valence oxo-centered trinuclear manganese complex Mn3O(O2CPh)6 (Py)3 was prepared in pyridine solvent and its crystal structure has been determined. C57H45O13N3Mn3, Mr =1144. 81, trigonal, space group R3,(No.148), unit cell parameters(H cell): a=b=43. 605 (7), c=15. 756(4), V =25946(10),Z=18, Dc=1.32 g/cm￣3 , F(000) = 10566.The final values of R and Rw are 0. 098 and 0. 087 respectively for 3087 observed reflections with Ⅰ>4σ(Ⅰ). The distances of Mn(1)-O(1), Mn(2)-O(1) and Mn(3)-O(1) are 1.855(10),1. 817(8) and 2. 089 (8), respectively, indicating the title compound is a valence-trapped situation.

Hydrothermal Synthesis and Crystal Structure of a Manganese Complex

The title compound [Mn（Phen）（p-MBA）2]n（1） was synthesized via the hydro-thermal reaction of KMnO4 and NaOH with phen and p-methybenzoic acid（p-MBA） in water.The title compound was characterized by elemental analysis and infrared spectra.The crystal of 1 crystallizes in orthorhombic,space group Pbcn with a = 24.132（1）,b = 10.404（0）,c = 9.386（0） ,V = 2356.65（13） 3,Z = 4,C28H22MnN2O4,Mr = 505.42,Dc = 1.424 g/cm3,F（000） = 1044 and μ（MoKα） = 0.598 mm-1.The final R = 0.0781 and wR = 0.1363 for 1972 observed reflections with Ⅰ 〉 2σ（Ⅰ） and R = 0.0897 and wR = 0.1420 for all data.X-ray diffraction reveals that the Phen and p-methy benzoic acid ligand link the Mn atoms into a single one-dimensional coordination polymer,and extensive intermolecular π-π interactions lead these 1D chains to form a two-dimensional supramolecular architecture.

Synthesis, oxygenation and catalytic performance of manganese complex with p-aminomethyl benzoic acid Schiff base

The amino acid Schiff base complex (Sal-AMBA-Mn) was prepared with p-amino-methylbenzoic acid, salicylaldehyde and Mn(OAc)2·4H2O. Its structures was characterized with IR and UV spectra. Oxygenation mechanism of the complex in N, N-dimethylformamide solution was investigated. The results show that lower temperature is in favor of the oxygenation, and energy, enthalpy and entropy are -3.8 kJ/mol, -4.2 J/mol and -161.44 J/(mol·K), respectively. In the presence of the manganese complex, dehydroepiandrosterone acetate is effectively oxidized by molecular oxygen and the corresponding enone 7-ketodehydroepiandrosterone acetate is obtained. The yield is 62.1% when the oxidation is carried out under the reaction conditions of 60 ℃, 2 MPa of O2 pressure, C5H5N as a solvent and molar ratio of the substrate to the complex of 1:10.

Crystal Structure and Spectrum Properties of a Manganese Complex with Schiff Base Ligand,Mn (bzacen) (pyrimidine) (NCS)

The title complex C_(27)H_(26)MnN_5O_2S (M_r= 539. 53 ) crystallizes in monoclinic system, space group P2_1/α with α = 8. 357 (2) A, b = 19. 077 (4) A . c = 16. 267(3) A, β=95. 85(2)°, V=2580(2) A￣3, Z=4, F(000) = 1120, D_c= 1. 39 g/ cm￣3 and μ=0. 601 mm￣(-1)(MoKα). The final R and R_w are 0. 0638 and 0. 0876, respectively. The coordination geometry around Mn atom is a distorted octahedron with a equatorial plane N_2O_2 from the Schiff base ligand bzacen￣(2-), the axial atoms being two nitrogen atoms from a thiocyanate and a pyrimidine ligand. The shifts of v_c=N, v_c=O and v_c=C to lower frequencies in IR and Raman spectra indicate that the ligand bzacen￣(2-) has been coordinated to Mn atom through its nitrogen and oxygen atoms. The lines assigned to Mn-O and Mn-N vibrations were found in Raman spectrum. There is π～π￣* transition, d～π￣* charge-transfer transitions and d～d￣* transitions in electronic spectrum. The current potential curve in acetontrile reveals that Mn(Ⅲ)is in stable valence state.

Synthesis and Structure of the Manganese Complexwith 2-Aminopyridine N-oxide

The complex Mn(apo)6Cl2 (apo=2-aminopyridine N-oxide) was obtained by the reaction of MnCl2(4H2O with apo(HCl and NaOH in ethanol. A single-crystal X-ray study shows that the complex is mononuclear with octahedral coordination environment (MnC30H36N12O6Cl2). The oxygen atoms from apo ligands coordinate to the manganese atom forming Mn(apo)6Cl2. The compound Mn(apo)6Cl2 is hexagonally symmetric with space group R3, lattice constants: a = 12.010(2), b = 12.010(2), c = 20.232(4) ?, ( = 120(, V= 2527.4(7) ?3, Z=3, Mr =786.55, Dc=1.550 g/cm3, (= 0.614mm-1, F(000) = 1221, R = 0.0541, Rw = 0.0580 for 1229 reflections with I>2((I). The distances between Mn(II) and O atoms are in the range from 2.171(5) to 2.184(5) ?, and the distance between the chlorine anion and N atom of amido group is 3.3 ?. The dihedral angle between two adjacent pyridine ring planes is 59.19 (0.17)°.

Synthesis and Crystal Structure of Copper (Ⅱ) Compound with 3,3'-Azobispyridine Ligand [Cu(NO_3)_2(H_2O)_2(3,3'azpy)_2]

The title complex [Cu(NO3)2(H2O)2(3,3-azpy)2] (3,3?azpy = 3,3?azobispyridine) has been synthesized and characterized, and its crystal belongs to the triclinic system, space group P with the following crystallographic parameters: a = 7.4161(2), b = 8.1754(3), c = 10.7545(4) ? a = 92.958(2), b = 109.978(1), g = 93.369(2)? V = 609.96(4) ?, C20H20N10CuO8, Mr = 592.00, Dc = 1.612 g/cm3, m(MoKa) = 0.964 mm-1, F(000) = 303, Z = 1, the final R = 0.0494 and wR = 0.1269 for 1945 observed reflections (I > 2s(I)). X-ray analysis reveals that the Cu atom adopts a distorted octahedral (4 + 2) coordination. The four closer donor atoms include two N atoms of 3,3?azpy and two O atoms of the coordination aqua with the CuN and CuO distances of 2.014(3) and 1.974(3) ? respectively. Two longer out-of-plane CuO bonds (2.450(3) ? from nitrate complete the strongly distorted octahedral coordination of the Cu atom. Hydrogen bonds are formed through H atoms of each coordination aqua with the remaining N atoms of 3,3?azpy and O atoms of nitrate. A two-dimensional network is constructed by hydrogen bonds and p-p interactions.

Synthesis and Structure of an Interlock Network Frame of Cobalt(Ⅱ) Coordination Polymer {[Co(azpy)_2(NCS)_2]·1/4EtOH·1/2H_2O}_n (azpy=4,4′-Azobispyridine)

A compound {[Co(azpy)2(NCS)2]·1/4EtOH·1/2H2O}n(1), where azpy=4,4’-azobispyridine, was synthesized and characterized by means of IR, TGA-DTA, magnetic susceptibility and X-ray single crystal diffraction. It consists of two independent sets of fully interlocked two-dimensional networks with the dihedral angle 61.7°, organized in parallel stacks of the sheets which are made of edge-shared [Co(Ⅱ)]4squares separated by 0. 9062nm, and defined size rhombic channels. The thermal gravimetric analysis indicates that the framework is stable up to 198℃. The variable-temperature magnetic susceptibility measurements indicated that there is a weak antiferromagnetic interaction between the cobalt(Ⅰ) ions in the complex (1).

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 ℃.

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）.

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.

Synthcsis, Structure and Magnetochemistry of a New Hexanuclear Manganese Oxide Complex of the Formula [Mn_6O_2 (O_2CPh)_(10)(CH_3CN)_4]

The reported X-ray structure and magnetochemical properties of [Mn6O2 (OCPh)10, (CH3CN)4], effectively derived from [NBu4][Mn4O2(O2CPh)9 (H2O)] with equivalent of tren in CH3CN is shown.

Solvothermal Synthesis and Crystal Structures of Two Manganese Complexes [Mn（Ⅱ）（acac-）2（4,4＇-bipy）]n （bipy-4,4＇-bipyridine） and [Mn（Ⅲ）（acac-）3].4CO（NH2）2

Two special manganese complexes [Mn（II）（acac ）2（4,4＇-bipy）]n （bipy=4,4＇-bipyridine） （complex 1） and [Mn（II1）（acac-）3].4CO（NH2）2 （acacH=acetylacetone） （complex 2） were synthesized in the same strategy by sol- vothermal method. Single crystal X-ray diffraction revealed the complex 1 consists of one-dimensional infinite coordination chain, with the manganese centers bridged by 4,4＇-bipy. And free carbamides of complex 2 connect with each other through the hydrogen bonds to form a 14-membered carbamide ring and a zig-zag plane. Both enantiomers of Mn（III）（acac ）3 exist in the structure, forming a racemate. Furthermore, these enantiomers and those zig-zag planes are linked with hydrogen bonds to form an unique spatial network.

Synthesis and Structure of a Manganese(Ⅱ) Complex: [Mn_2·(dinitrobenzoic acid)_4·(1,10-phen)_2]_n

The title compound, [Mn2·（dinitrobenzoic acid）4·（1,10-phen）2]n, has a linear chain structure containing binuclear [Mn2·（dinitrobenzoic acid）4（1,10-phen）2] repeat units. It crystallizes in the triclinic system, space group Pi with a = 7.9261（8）, b = 12.1329（15）, c = 14.847（2）A, α = 103.845（5）, β = 101.424（5）, γ = 92.618（4）°, Mr= 657.37, V = 1352.3（2）A^3, Z = 2, De= 1.614 g/cm^3, F（000） = 666,μ = 0.567 mm^-1, the final R = 0.0407 and wR = 0.1015 for 4081 observed reflections with I 〉 2σ（I）. The Mn atom is six-coordinated by two N and four O atoms, forming a slightly distorted octahedral geometry. All Mn-O and Mn-N bond distances range from 2.093（2） to 2.310（2）A. Two adjacent octahdral units are bridged together by two pairs of bi-monodentate carboxyl groups of different dinitrobenzoic acids to form an eight-membered ring with chair-typed configuration, thus generating a one-dimensional chain along the a axis.

Synthesis and Structure of a Manganese(Ⅱ) Complex [Mn·(p-Methoxybenzoato)_2·(2,2'-bipy)·H_2O]·(p-methoxybenzoic Acid)

The title compound, {[MnL2·（2,2＇-bipy）-H2O]-（HL）}, has been synthesized （HL = p-methoxybenzoic acid, 2,2＇-bipy = 2,2＇-bipyridine） by the reaction of MnCl2-6H2O with p-methoxybenzoic and 2,2＇-bipyridine in an alcohol-water solution. It crystallizes in the tricfinic system, space group PI with α = 10.1138（5）, b = 11.2811（5）, c = 16.2210（8） A, α = 77.5920（10）,β = 72.1890（10）, γ = 66.2320（10）°, Mr = 683.56, V=1603.65（13） A3, Z= 2, Dc = 1.416 g/cm^3, F（000） = 710,μ = 0.473 mm^-1, the final R = 0.0619 and wR = 0.1571 for 4724 observed reflections with I 〉 20（I）. The structure determined demonstrated that it is an isomeric modification of the structure reported before. The Mn atom is six-coordinated by two N and four O atoms, forming a distorted octabedral geometry. All Mn-O and Mn-N distances range from 2.113（3）-2.410（3） A. There also exists a dissociative p-methoxybenzoic acid beside the octahedron.

Synthesis and Crystal Structure of a Bimetallic Cyanide-bridged Complex Derived from Manganese(Ⅲ) Schiff-base Complex and Pentacyanidonitrosylferrate(Ⅱ) Building Blocks

A new cyanide-bridged bimetallic assembly [Mn（3-meosalpn）（H2O）]2[Fe（CN）5NO]（1） was obtained by the reaction of [Fe（CN）5NO]2-with [Mn（3-meosalpn）]＋,and characterized by elemental analysis,IR and single-crystal X-ray structure analysis.The complex crystallizes in the monoclinic system,space group P21/c with a = 12.992（5）,b = 13.274（6）,c = 14.644（6） ,β = 115.198（4）o,V = 2285.2（16）3,Z = 2,C43H44FeMn2N10O11,Mr = 1042.61,Dc = 1.515 g/cm3,F（000） = 1072,μ = 0.928 mm-1,S = 1.052,the final R = 0.0347 and wR = 0.0957 for 17377 observed reflections（Ⅰ 〉 2σ（Ⅰ））.X-ray single-crystal diffraction analysis reveals that 1 has a trinuclear molecular structure,in which the two [Mn（3-meosalpn）（H2O）]＋ cations are linked by the central [Fe（CN）5NO]2-anion via two trans CN-groups.Furthermore,the two [Mn（3-meo-salpn）（H2O）]＋ cations and [Fe（CN）5NO]2-anion are connected into a one-dimensional zigzag chain through hydrogen bonding interactions.

Theoretical and experimental investigations of the enantioselective epoxidation of olefins catalyzed by manganese complexes

The enantioselective epoxidation of olefin by Mn^(II)(R,R-PMCP)(OTf)2, H_(2)O_(2) and H_(2)SO_(4) was explored by DFT calculations and experiments. Theoretical results suggest that [Mn^(V)(O)(R,R-PMCP)(SO_(4))]^(+) species with a triplet ground spin state serves as the active species for the olefin epoxidation. It can be generated by the H_(2)SO_(4) assisted O-O heterolysis of Mn^(III)(OOH) species. Mn^(III)-persulfate is also involved in this system, but it cannot promote the olefin epoxidation directly, preferring instead to transform into Mn^(V)(O). Actually, the asymmetric epoxidation reactions with H_(2)O_(2)/H_(2)SO_(4) or Oxone provide similar enantioselectivity in the presence of manganese catalyst. These observations further support the transformation of Mn^(III)-persulfate to Mn^(V)(O) species.