MnII Cations Research Articles

Catena-Poly[[[diaqua(1,3-benzimidazole-κN3)manganese(II)]-μ-benzene-1,3-dicarboxylato-κ3O1,O1′:O3] dihydrate

In the polymeric title complex, {[Mn(C8H4O4)(C7H6N2)(H2O)2]·2H2O}n, the MnII cation is coordinated by two benzene­dicarboxyl­ate anions, one benzimidazole ligand and two water mol­ecules in a distorted MnNO5 octa­hedral geometry. In the crystal, each benzene­dicarboxyl­ate anion bridges adjacent MnII cations through the terminal carboxyl­ate groups, forming a polymeric complex chain along the a axis. One Mn—Ocarboxyl­ate bond is much longer than the others. In the crystal, π–π stacking is observed between nearly parallel [dihedral angle = 4.32 (6)°] benzimidazole aromatic ring systems of adjacent mol­ecules, the centroid–centroid distance between the imidazole and benzene rings being 3.5421 (11) Å. Extensive inter­molecular O—H⋯O and N—H⋯O hydrogen bonding is present in the crystal structure. The two lattice water mol­ecules are located on twofold rotation axes.

Isomorphous Catena Transition Metal Squarates [MII(C4O4)(dmso)2(OH2)2] (M = Co, Mn) and Magnetic Investigation into their Solid Solution M = CoxMn1–x

AbstractThe crystal structures of two new isomorphous transition metal squarato complexes [MII(C4O4)(dmso)2(OH2)2] [MII = CoII (3d7), MnII (3d5); dmso = dimethylsulfoxide] and their magnetic properties are reported. The compounds feature two symmetrically independent chains, in which 1,3‐bridging squarato ligands connect cations in distorted octahedral surroundings of pseudo‐symmetry D4h. From an equimolar solution of CoCl2·6H2O and MnCl2·2H2O a mixed‐metal coordination polymer crystallizes; it represents a solid solution and adopts the same structure as the corresponding monometallic compounds. The results of the diffraction experiment unambiguously proof the presence of both CoII and MnII cations in either independent site albeit no precise ratio between the metal cations involved may be deduced from these findings. The difference in the magnetic properties between CoII and MnII cations in the given ligand field has allowed us to establish their ratio in the solid solution more reliably than by X‐ray diffraction: Accounting for ligand field potential and spin‐orbit coupling of CoII and regarding MnII as a pure spin system, the calculations yielded a fraction of 73 % CoII in the mixed‐metal polymer. With respect to superexchange effects only weak antiferromagnetic interactions have been detected for the three coordination polymers.

Seven-coordinate Manganese(II) Complex Formed with the Tripodal Tetradentate Ligand Tris(N-methylbenzimidazol-2-ylmethyl)amine

A seven-coordinate manganese(II) complex with the tripodal tetradentate ligand tris(N-methylbenzimidazol- 2-ylmethyl)amine (Mentb), with composition [Mn(Mentb)(α-methacrylate)(DMF)]- (ClO4) · (DMF), was synthesized and characterized by elemental analysis, electrical conductivity, and IR and UV/Vis spectral measurements. The crystal structure of the complex has been determined by single-crystal X-ray diffraction. The MnII cation is bonded to a Mentb ligand, an α-methacrylate ligand and a DMF molecule through four N atoms and three O atoms, resulting in a seven-coordinate geometry. Cyclovoltammograms of the complex indicate a quasireversible Mn3+/Mn2+ couple. The X-band EPR spectrum of the complex exhibits a six-line manganese hyperfine pattern with g = 2, A = 91, and confirms that the material is high-spin Mn(II).

Diaqua-bis-(5-carb-oxy-2-propyl-1H-imidazole-4-carboxyl-ato-κN,O)manganese(II) 3.5-hydrate.

In the title complex, [Mn(C8H9N2O4)2(H2O)2]·3.5H2O, the MnII cation is six-coordinated by two N,O-bidentate H2pimda− ligands (H2pimda− = 5-carb­oxy-2-propyl-1H-imidazole-4-carboxyl­ate) and two water mol­ecules in a distorted octa­hedral environment. The complete solid-state structure can be described as a three-dimensional supra­molecular framework stabilized by a wide range of O—H⋯O and N—H⋯O hydrogen bonds. The propyl groups of H2pimda− are disordered over two sets of sites with refined occupancies of 0.759 (5):0.241 (5) and 0.545 (7):0.455 (7).

Catena-Poly[[bis(acetonitrile-κN)manganese(II)]-bis(μ-trifluoromethanesulfonato-κ2O:O′)

The title compound, [Mn(CF(3)SO(3))(2)(CH(3)CN)(2)](n), has an Mn(II) cation on an inversion centre in an octahedral environment. The trifluoromethanesulfonate anions act as bridging ligands and form a one-dimensional coordination polymer in the direction of the a axis. The F atoms of the trifluoromethanesulfonate anions form layers parallel to the ab plane, but despite short intermolecular distances, no stabilizing F...F interactions are detected. The Mn-N and C-C bonds of the acetonitrile ligand are analyzed according to the Hirshfeld rigid-bond test. Renninger effects in the reflection data are considered, explored and discussed.

Three types of heterometallic structural motifs based on [Mo(CN)8]3−/4− anion and MnII cation as building blocks

The reaction between K3[Mo(CN)8] · H2O and MnCl2 · 4H2O in different reaction conditions have obtained three new bimetallic cyanide-bridged compounds, namely, {(tetrenH2)0.5[Mn(H2O)2][MoV(CN)8] · 2H2O}n (1) (where, tetren is tetraethylenepentamine), {[Mn2(H2O)4][MoIV(CN)8] · 3H2O}n (2), and {[Mn2(H2O)4][MoIV(CN)8] · 4H2O}n (3). Compound 1 crystallizes in the orthorhombic system with space group Cmc21 and unit cell constants a = 7.8234(15), b = 26.013(5), c = 10.021(2) A, β = 90°, and Z = 4. Compound 2 crystallizes in the monoclinic system with space group P21/n and unit cell constants a = 7.3329(11), b = 14.372(2), c = 18.070(3) A, β = 90.869(2)°, and Z = 4. Compound 3 crystallizes in the tetragonal system with space group I4/m and unit cell constants a = b = 11.9371(8), c = 13.2930(18) A, β = 90°, and Z = 4. X-ray single-crystal structures reveal that the Mo centers adopt a distorted square antiprism coordination environment for 1 and 3, while 2 closed to a bicapped trigonal prism. For these complexes, all the MnII centers in the extended structure adopt distorted octahedron geometry. For 1, each MoV coordinated via four cyanide groups to four MnII ions, and the other four cyanide groups are terminal, forming a two-dimensional framework. For 2, the MoIV center of structural unit coordinated via four cyanide groups to four Mn(1), and the other four cyanide groups coordinated to four Mn(2), forming a three-dimensional framework. For 3, each [MoIV(CN)8]4− building block is linked to MnII ions through its eight CN ligands, and each MnII center is connected to four Mo units forming a three-dimensional framework. In addition, magnetic studies of these complexes have also been presented.

Modeling the Resting State of Oxalate Oxidase and Oxalate Decarboxylase Enzymes

In view of the biological and commercial interest in models for Oxalate Decarboxylases (OxDC) and Oxalate Oxidases (OxOx), we have synthesized and characterized three new Mn (II) complexes ( 1- 3) employing N3O-donor amino-carboxylate ligands (TCMA, 1,4,7-triazacyclononane- N-acetic acid; K (i) Pr 2TCMA, potassium 1,4-diisopropyl-1,4,7-triazacyclononane- N-acetate; and KBPZG, potassium N,N-bis(3,5-dimethylpyrazolyl methyl)glycinate). These complexes were characterized by several techniques including X-ray crystallographic analysis, X-band electron paramagnetic resonance (EPR), electrospray ionization mass spectrometry (ESI-MS), and cyclic voltammetry. The crystal structures of 1 and 3 revealed that both form infinite polymeric chains of Mn (II) complexes linked by the pendant carboxylate arms of the TCMA (-) and the BPZG (-) ligands in a syn-antipattern. Complex 2 crystallizes as a mononuclear Mn (II) cation, six-coordinate in a distorted octahedral geometry. Although complexes 1 and 3 crystallize as polymeric chains, all compounds present the same N3O-donor set atoms around the metal center as observed in the crystallographically characterized OxDC and OxOx. Moreover, complex 2 also contains two water molecules coordinated to the Mn center as observed in the active site of OxDC and OxOx. ESI-MS spectrometry, combined with EPR, were useful techniques to establish that complexes 1- 3 are present as mononuclear Mn (II) species in solution. Finally, complexes 1- 3 are able to model the resting state active sites, with special attention focused on complex 2 which provides the first exact first coordination sphere ligand structural model for the resting states of both OxDC and OxOx.

Bimetallic Metal‐Organic Frameworks Containing the ${\rm [M(2,}x-{\rm pdc)^{2-}_{2}}]$ (M = Cu, Pd, Pt; x = 4, 5) Building Block – Synthesis, Structure, and Magnetic Properties

AbstractNew bimetallic coordination polymers containing the ${\rm [Cu(2,}x-{\rm pdc)^{2-}_{2}}]$ (pdc = pyridine dicarboxylate, NC5H3(CO2)2; x = 4,5) ‘metalloligand’ unit, linked by MnII or CoII cations, have been obtained by hydrothermal synthesis. The metalloligand species K2[Cu(2,x−pdc)2(OH2)n]·mH2O (1, 2) were reacted under basic conditions with MnCl2 at 200 °C to form the compounds [CuMn(2,x−pdc)2] (3, x = 4; 4, x = 5), which are unexpectedly isostructural. Similar reaction with CoCl2 gave [Co3Cu2(2,4–pdc)4(μ4−OH)2(OH2)]2 (5), which has a ladder‐like framework based on Co‐hydroxide chains, and the 2‐dimensional sheet polymer [CoCu(2,4‐pdc)2(OH2)4] (6). A related CuII‐only chain compound, [Cu2(2,5−pdc)2(OH2)2]·4H2O (7) is also reported. The compounds 1–7 have been structurally characterized by single crystal X‐ray diffraction. The DC magnetic susceptibilites of 3–6 and [M3M′2(2,4−pdc)4(μ4−OH)2(OH2)] (8: M = Co, M′ = Pd; 9: M = Co, M′ = Pt; 10: M = Ni, M′ = Pd; 11: M = Ni, M′ = Pt) have been studied by SQUID magnetometry; 3 and 4 undergo antiferromagnetic ordering at low temperature, 5, 8 and 9 are metamagnets, 6 exhibits weak ferromagnetic exchange, while 10 and 11 show canted antiferromagnetism.

Poly[chlorido(μ3-1,2,4-triazolato)manganese(II)

The title compound, [Mn(C2H2N3)Cl]n, has been prepared by the hydro­thermal reaction of manganese(II) chloride and 1,2,4-triazole. The MnII cation is surrounded by three N atoms belonging to three different triazolate ligands and a Cl atom, and exhibits a slightly distorted tetra­hedral coordination geometry. A polymeric layer is formed by the triply bridging nature of the 1,2,4-triazolate ligand bonded to three different MnII atoms through its three N atoms. The layer contains both binuclear units and tetra­nuclear macrocyclic units. In the binuclear unit, two Mn atoms are bridged by two nearly coplanar triazolate groups through the 1,2-positions, affording a six-membered ring around an inversion center. Each binuclear unit is further connected to four parallel units through the other four N atoms of the triazolate groups. Four adjacent units, which are pairwise parallel, afford 16-membered tetra­nuclear macrocyclic units. In each of these, the two nearest-neighbor Mn atoms are bridged by a single triazolate group through the 1,4-positions.

Synthesis, crystal structure and magnetic properties of novel heterobimetallic malonate-bridged MIIReIV complexes (M = Mn, Fe, Co and Ni)

Five novel ReIV-MII bimetallic complexes of formula [ReCl4(mu-mal)M(dmphen)2].MeCN [M = Co (1), Fe (2) and Ni (3)], [ReCl4(mu-mal)Ni(dmphen)(MeCN)2(H2O)].(MeCN)0.5(H2O)0.5 (4), and [ReCl4(mu-mal)Mn(dmphen)(H2O)2].dmphen.MeCN.H2O (5) (mal = malonate dianion, dmphen = 2,9-dimethyl-1,10-phenanthroline) have been synthesized, and the structures of 1, 2, 4, and 5 determined by single-crystal X-ray diffraction. The structures of 1 and 2 consist of neutral [ReCl4(mu-mal)M(dmphen)2] dinuclear units where the metal ions are linked through a malonate ligand which adopts simultaneously the bidentate (at ReIV) and monodentate (at MII) coordination modes. The bridging carboxylate-malonate group in them exhibits the anti-syn conformation. The rhenium atom is six-coordinated with four chloro atoms and two carboxylate-oxygens from a bidentate malonate group in a distorted octahedral environment. The M atom is five-coordinated being surrounded by four nitrogen atoms of two bidentate dmphen ligands and one oxygen atom of the malonato ligand. There are also ReIV(mu-mal)NiII dinuclear units in 4 with the same type of bridge, but the nickel atom is six-coordinated with one bidentate dmphen, two molecules of acetonitrile and one water molecule as peripheral ligands. Compound 5 is a neutral chain compound with regular alternating rhenium(IV) and manganese(II) ions. The [ReCl4(mal)]2- units in each chain act as bismonodenate ligands through two carboxylate-oxygen atoms toward [Mn(dmphen)(H2O)2]2+ entities. Variable-temperature magnetic measurements of 1-5 in the temperature range 2.0-300 K show the occurrence of weak antiferromagnetic interactions which are rationalized on the basis of the structural knowledge and simple orbital considerations. Very noticeable is compound 5, a ferrimagnetic chain with regular alternating ReIV and MnII cations.

Ba7Mn5Cr2O20: charge and chemical order

Ba7Mn5Cr2O2O20 adopts a structure containing an ordered array of Mn(IV), Mn(II) and Cr(V) cations and exhibits complex magnetic behaviour at low temperature.

μ-2,10,15,23-Tetramethyl-3,6,9,12,13,16,19,22,25,26,27,28-dodecaazatricyclo[22.2.1.111,14]hexacosa-1(26),2,9,11(28),13,15,22,24(27)-octaene-12,25-diido-1κ5N13,N16,N19,N22,N25:2κ5N3,N6,N9,N12,N26]bis[diaquamanganese(II)] dichloride hexahydrate

The title centrosymmetric dinuclear complex, [Mn2(C20H30N12)(H2O)4]Cl2·6H2O, consists of a dimanga­nese(II) macrocyclic complex in which the MnII centres are linked by two triazolate units of the macrocyclic framework. In the complex, the MnII cation is coordinated by five N atoms from the macrocycle and two O atoms from the coordinated water mol­ecules. The MnII centre is in an approximately pentagonal–bipyramidal environment. Adjacent ions and water mol­ecules are linked to form a one-dimensional chain via O—H⋯O and O—H⋯N hydrogen bonds.

Poly[di-μ-chloro-bis(1,10-phenanthroline)-μ4-terephthalato-dimanganese(II)

In the structure of the title complex, [Mn2(C8H4O4)Cl2(C12H8N2)2], each MnII cation is surrounded by two O atoms from two terephthalate dianions, two bridging Cl atoms and two N atoms from a 1,10-phenanthroline mol­ecule in a distorted octa­hedral geometry. Each terephthalate dianion functions as a μ4-bridging ligand to form a zigzag chain. Neighbouring chains are held together by μ-chloro bridges, which create a three-dimensional architecture.

Structural and Magnetic Properties of Two Carboxylato‐Bridged Manganese(II) Complexes with N‐Donor Coligands

AbstractTwo polymeric MnII complexes, [(m‐phth)(Mn)(bpp)2]·0.5H2O (1) and [(mal)2(Mn)2(H2O)2(hmt)] (2) [mal = malonate; hmt = hexamethylenetetramine; bpp = 1,3‐bis(4‐pyridyl)propane; m‐phth = 1,3‐benzenedicarboxylate] have been synthesized. Complex 1 consists of 1D chains (with monocoordinated bpp) that are held together to form a 2D extended network of hydrogen bonding between lattice water molecules and uncoordinated bpp donors. Variable‐temperature magnetic susceptibility data of the complex have been fitted applying the formula used for dinuclear complexes of MnII ions, considering interdimer interactions (J′). The following parameters were obtained from the best fit: J = −0.88 ± 0.02 cm−1, J′ = −0.1 cm−1 and g = 1.99 ± 0.01. The agreement factor R = Σ(χmTobsd. − χmTcalcd.)2/Σ(χmTcalcd.)2 is 1.110−5. Complex 2 is a 3D polymeric network where syn/anti‐bridging malonate ligands and MnII centers are assembled in the form of [Mn(H2O)(mal)]n layers, which are further connected by hexamethylenetetramine. The magnetic data have been fitted considering the complex as a pseudo‐two‐dimensional sheet of MnII cations and malonate anions since the coupling through the hexamethylenetetramine ligand is almost zero. We have followed two approaches for fitting the data, (a) through the expansion series of Line’s equation for the S = 5/2 antiferromagnetic quadratic layer and (b) by using the equation based on an infinite 2D square lattice composed of isotropically coupled classical spin S = 5/2. Both approaches result in excellent theoretical fits and similar J values of −0.24 cm−1 and −0.21 cm−1 for the Line’s and Curély equations, respectively. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

Redetermination ofcatena-poly[[diaquamanganese(II)]-μ-iminodiacetato-κ4N,O,O′:O′′

The redetermined structure of the title compound, [Mn(C4H5NO4)(H2O)2]n, including the full hydrogen-bonding scheme, is reported; the original report was by Zhang & Lu [Acta Cryst. (2004). E60, m1189–m1190]. The structure contains polymeric chains of MnII cations bridged by imino­di­acetate (IDA) dianions. The manganese species assumes a distorted octahedral coordination geometry, formed by two IDA mol­ecules (one tridentate and one monodentate) and two water mol­ecules. The tridentate IDA chelates to the Mn atom in the facial configuration; one chelating five-membered ring is almost planar and the other adopts an envelope configuration. A significant difference of 0.118 (2) A in Mn—Ocarboxyl bond distances is observed within the chelating IDA moiety.

A novel bridged asymmetric binuclear manganese(II) complex with DTPB [DTPB is 1,1,4,7,7-pentakis(1H-benzimidazol-2-ylmethyl)-1,4,7-triazaheptane

The crystal structure of the title compound, tetrachloro[micro-1,1,4,7,7-pentakis(1H-benzimidazol-2-ylmethyl)-1,4,7-triazaheptane]dimanganese(II) methanol pentasolvate tetrahydrate, [Mn(2)Cl(4)(C(44)H(43)N(13))].5CH(4)O.4H(2)O, contains an asymmetric dinuclear Mn(II)-DTPB [DTPB is 1,1,4,7,7-pentakis(1H-benzimidazol-2-ylmethyl)-1,4,7-triazaheptane] complex with an intra-ligand bridging group (-NCH(2)CH(2)N-), as well as several solvate molecules (methanol and water). Both Mn(II) cations have similar distorted octahedral coordination geometries. One Mn(II) cation is coordinated by a Cl(-) anion and five N atoms from the ligand, and the other is coordinated by three Cl(-) anions and three N atoms of the same ligand. The Mn.Mn distance is 7.94 A. A Cl.H-O.H-O.H-N hydrogen-bond chain is also observed, connecting the two parts of the complex.

Hexaaquamanganese(II) 3-carboxy-4-hydroxybenzenesulfonate dihydrate

In the title compound, [Mn(H2O)6]L2·2H2O, where HL is 3-carboxy-4-hydroxy­benzene­sulfonic acid (C7H6O6S), each MnII cation lies on an inversion center and is octahedrally coordinated by six water mol­ecules. The L− anions do not coordinate to manganese, but act as counter-anions. The crystal structure is composed of alternating layers of [Mn(H2O)6]2+ cations and sulfonate anions. The [Mn(H2O)6]2+ cations, water mol­ecules and L− anions are connected through a complex pattern of H-bonding interactions.

A New Alternating Ferro- and Antiferromagnetic, One-Dimensional Manganese(II) Azide Complex, [Mn(dpa)(N3)2] − Crystal Structure and Spectroscopic and Magnetic Properties

The synthesis, crystal structure, and spectroscopic and magnetic properties of a new alternating ferro- and antiferromagnetic, one-dimensional manganese(II) azide complex, [Mn(dpa)(N3)2] (where dpa is the 2,2′-dipyridylamine ligand), are reported. The compound’s crystal structure has been resolved at room temperature. The complex crystallizes in the monoclinic P21/c space group, with a = 7.089(2), b = 19.090(4), and c = 9.682(4) Å, β = 104.61(2) °, and Z = 4. The structure consists of neutral chains in which each MnII cation is alternatively bridged by two end-on and two end-to-end azido bridges. The octahedral coordination of the metallic cation is completed by two dpa ligand nitrogen atoms. Reflectance measurements confirm the hexacoordination of the MnII ions in the complex. The ESR spectra at room temperature and at 4.2 K are isotropic, with a mean g-value of 2.010(1). Magnetic data were analyzed on the basis of an alternating ferro- and antiferromagnetic Heisenberg chain of MnII ions. The J-exchange parameters found are 64.3 and −75.7 K. A spin canting phenomenon has been observed in this compound, with a remnant magnetization which vanishes above 15 K. Magnetostructural correlations in manganese(II) systems of alternating magnetic sign are discussed.

A New Alternating Ferro- and Antiferromagnetic, One-Dimensional Manganese(II) Azide Complex, [Mn(dpa)(N3)2] − Crystal Structure and Spectroscopic and Magnetic Properties

The synthesis, crystal structure, and spectroscopic and magnetic properties of a new alternating ferro- and antiferromagnetic, one-dimensional manganese(II) azide complex, [Mn(dpa)(N3)2] (where dpa is the 2,2′-dipyridylamine ligand), are reported. The compound’s crystal structure has been resolved at room temperature. The complex crystallizes in the monoclinic P21/c space group, with a = 7.089(2), b = 19.090(4), and c = 9.682(4) Å, β = 104.61(2) °, and Z = 4. The structure consists of neutral chains in which each MnII cation is alternatively bridged by two end-on and two end-to-end azido bridges. The octahedral coordination of the metallic cation is completed by two dpa ligand nitrogen atoms. Reflectance measurements confirm the hexacoordination of the MnII ions in the complex. The ESR spectra at room temperature and at 4.2 K are isotropic, with a mean g-value of 2.010(1). Magnetic data were analyzed on the basis of an alternating ferro- and antiferromagnetic Heisenberg chain of MnII ions. The J-exchange parameters found are 64.3 and −75.7 K. A spin canting phenomenon has been observed in this compound, with a remnant magnetization which vanishes above 15 K. Magnetostructural correlations in manganese(II) systems of alternating magnetic sign are discussed.

Part I. A comparative electrochemical study of transition metal substituted Dawson type heteropolyanions

The comparative electrochemical behaviour, in aqueous solutions, of the Dawson lacunary anion [P2W17O61]10− and of the FeIII, CuII, CoII, NiII, MnIII and MnII substituted Dawson lacunary heteropolyanions is presented. The literature concerning the latter heteropolyanions has been reviewed and completely new data are presented. The electrochemical behaviour observed for the reduction of the tungsten oxo centres, for all the heteropolyanions investigated, was found to be pH dependent. Electrochemical evidence for the presence of the FeIII, CuII, CoII and the MnII and MnIII cations in the ejected tungsten position was obtained with the NiII cation processing no electroactivity.