Study of the Two-Dimensional [MM‘(C3H2O4)2(H2O)4] (M = Ba, Sr and M‘ = Cu, Mn) Systems: Synthesis, Structure, Magnetic Properties, and Thermal Decomposition

Oxalato bridged coordination polymer of manganese(iii) involving unconventional O⋯π-hole(nitrile) and antiparallel nitrile⋯nitrile contacts: antiproliferative evaluation and theoretical studies

Unconventional O⋯π-hole(nitrile) and antiparallel nitrile⋯nitrile contacts have been theoretically investigated for a Mn(iii) coordination polymer considering cytotoxicity, apoptosis, ROS generation, molecular docking and pharmacophore features.

Unprecedented tetranuclear complexes with “weighing balance shaped” topology: single crystal structures, unusual EPR spectra, magnetic properties and antioxidant activity

Two new copper(ii) complexes have been synthesized and characterized by single crystal X-ray diffraction.

Crystal structure of hexaaqua-bis(3-(3-pyridin-4-yl-[1,2,4]oxadiazol-5-yl) propionato-κ3O,O′:O′)-bis(3-(3-pyridin-4-yl-[1,2,4]oxadiazol-5-yl)propionato-κO)-bis(3-(3-pyridin-4-yl-[1,2,4]oxadiazol-5-yl)propionato-κ2O,O′)dineodymium(III) octahydrate, C60H76N18O32Nd2

C60H76N18O32Nd2, monoclinic, P21/c (no. 14), a = 10.609(5) Å, b = 31.215(5) Å, c = 12.407(4) Å, β = 116.54(3)°, V = 3676(2) Å3, Z = 2, R gt(F) = 0.0450, wR ref(F 2) = 0.0910, T = 293(2) K.

The crystal structure of hexaqua(μ2-3-(3-(pyridin-4-yl)-1,2,4-oxadiazol-5-yl)propanoato-1κ2 O,O′;2κO′)(3-(3-(pyridin-4-yl)-1,2,4-oxadiazol-5-yl)propanoato-κO)(3-(3-(pyridin-4-yl)-1,2,4-oxadiazol-5-yl)propanoato-κ2 O,O′)digadolinium(III) octahydrate, C60H76Gd2N18O32

C60H76N18O32Gd2, monoclinic, P21/c (no. 14), a = 10.560(5) Å, b = 31.243(5) Å, c = 12.383(4) Å, β = 116.51(3)°, V = 3656(2) Å3, Z = 2, R gt (F) = 0.0470, wR ref (F 2 ) = 0.1013, T = 293(2) K.

Crystal growth and structural remarks on malonate-based lanthanide coordination polymers

The synthesis, structural and thermal studies of several malonate-containing lanthanide(iii) complexes plus a structural overview of twenty-three known homometallic Ln(iii)-malonate systems are provided herein.

Long-range antiferromagnetic order in malonate-based compounds Na2M(H2C3O4)2·2H2O (M = Mn, Fe, Co, Ni)

Newly synthetized metal malonates of formulae Na₂M(H₂C₃O₄)₂·2H₂O (M = Mn, Fe, Co, Ni) exhibit distinct long-range antiferromagnetic orders despite their similar structure and chemistry.

Oxalate-mediated long-range antiferromagnetism order in Fe2(C2O4)3·4H2O

Neutron powder diffraction and susceptibility measurements reveal the long range antiferromagnetic order mediated by oxalate molecules in Fe₂(C₂O₄)₃·4H₂O.

Synthesis, DFT calculations of structure, vibrational and thermal decomposition studies of the metal complex Pb[Mn(C3H2O4)2(H2O)2]

The metallo-organic complex Pb[Mn(C3H2O4)2(H2O)2] was synthesized and characterized by IR and Raman spectroscopy and powder X-ray diffraction methods. The cell parameters for the complex were determined from powder X-ray diffraction using the autoindexing program TREOR, and refined by the Le Bail method with the Fullprof program. A hexagonal unit cell was determined with a=b=13.8366(7)Å, c=9.1454(1)Å, γ=120°. The DFT calculated geometry of the complex anion [Mn(C3H2O4)2(H2O)2](2-) is very close to the experimental data reported for similar systems. The IR and Raman spectra and the thermal analysis of the complex indicate that only one type of water molecules is present in the structure. The thermal decomposition of Pb[Mn(C3H2O4)2(H2O)2] at 700 °C in air produces PbO and Pb2MnO4 as final products. The crystal structure of the mixed oxide is very similar to that reported for Pb3O4.

Robust recognition of malonate and 2-amino-4-picolinium in conjunction with M(II) as a triad (M = Ni/Co/Mn): role of this highly stable hydrogen-bonded motif in driving supramolecular self-assembly

The crystal lattice of the three isostructural compounds , (C(6)H(8)N(2)H)(2)[M(C(3)H(2)O(4))(2)(H(2)O)(2)].4H(2)O (C(6)H(8)N(2)H = protonated 2-amino-4-picoline, M = Ni/Co/Mn, C(3)H(4)O(4) = malonate dianion; hereafter, malonate) is formed by supramolecular 2D layers. Hydrogen-bonding, pi...pi and lone pair...pi interactions play crucial role in organizing monomeric [M(II)(mal)(2)(H(2)O)(2)] units into 2D sheets along the ab plane, through the self-association between two different supramolecular building blocks, namely a tetrameric water cluster including metal-coordinated water molecules, and R(2)(2)(8) and R(2)(2)(7) hydrogen-bonded recognition synthons between 2-amino-4-picolinium and malonate. DFT calculations clearly show that the robust 2-amino-4-picolinium/malonate hydrogen-bonded motif drives the self-assembly of the supramolecular network observed.

Malonate-Containing Manganese(III) Complexes: Synthesis, Crystal Structure, and Magnetic Properties of AsPh4[Mn(mal)2(H2O)2]

The novel manganese(III) complexes PPh4[Mn(mal)2(H2O)2] (1) and AsPh4[Mn(mal)2(H2O)2] (2) (PPh4+ = tetraphenylphosphonium cation, AsPh4+ = tetraphenylarsonium cation, and H2mal = malonic acid) have been prepared, and the structure of 2 was determined by X-ray diffraction analysis. 2 is a mononuclear complex whose structure is made up of trans-diaquabis(malonato)manganate(III) units and tetraphenylarsonium cations. Two crystallographically independent manganese(III) ions (Mn(1) and Mn(2)) occur in 2 that exhibit elongated octahedral surroundings with four oxygen atoms from two bidentate malonate groups in equatorial positions (Mn(1)-O = 1.923(6) and 1.9328(6) A and Mn(2)-O = 1.894(6) and 1.925(6) A) and two trans-coordinated water molecules in the axial sites (Mn(1)-Ow = 2.245(6) A and Mn(2)-Ow = 2.268(6) A). The [Mn(mal)2(H2O)2]- units are linked through hydrogen bonds involving the free malonate-oxygen atoms and the coordinated water molecules to yield a quasi-square-type anionic layer growing in the ab plane. The shortest intralayer metal-metal separations are 7.1557(7) and 7.1526(7) A (through the edges of the square). The anionic sheets are separated from each other by layers of AsPh4+ where sextuple- and double-phenyl embraces occur. The magnetic behavior of 1 and 2 in the temperature range 1.9-290 K reveals the occurrence of weak intralayer ferromagnetic interactions (J = +0.081(1) (1) and +0.072(2) cm(-1) (2)). These values are compared to those of the weak antiferromagnetic coupling [J = -0.19(1) cm(-1)], which is observed in the chain compound K2[Mn(mal)2(MeOH)2][Mn(mal)2] (3), where the exchange pathway involves the carboxyate-malonate bridge in the anti-syn conformation. The structure of 3 was reported elsewhere. Theoretical calculations on fragment models of 2 and 3 were performed to analyze and substantiate both the nature and magnitude of the magnetic couplings observed.

Incorporation of Triazacyclononane into the Metal Phosphonate Backbones

This paper reports the syntheses and crystal structures of a manganese and a uranyl phosphonate based on 1,4,7-triazacyclononane-1,4,7-triyl-tris(methylenephosphonic acid), namely, Mn3{C9N3H18(PO3)3}(H2O)6 x 1.5 H2O (1) and UO2{C9N3H19(PO3H)3} x H2O (2). Compound 1 shows a unique layer structure where the hydrophobic triazacyclononane moieties all reside on one side of the inorganic backbone of the manganese phosphonate layer while the hydrophilic coordinated water molecules reside on the other side. In compound 2, the triazacyclononane moieties are immobilized on the inorganic backbone of the uranyl phosphonate chains. The magnetic properties of compound 1 and the ion exchange properties of compound 2 have been studied.

Metamagnetism in hydrophobically induced carboxylate (phenylmalonate)-bridged copper(ii) layers

Self-assembly of copper(l) ions, phenylmalonate and pyrimidine yields the layered compound [Cu(pym)(Phmal)n (1) where intralayer ferro- and interlayer antiferromagnetic interactions occur with three-dimensional antiferromagnetic ordering at T(c) = 2.15 K.

Synthesis, Structures, and Magnetic Properties of the Copper(II), Cobalt(II), and Manganese(II) Complexes with 9-Acridinecarboxylate and 4-Quinolinecarboxylate Ligands

To explore the relationships between the structures of ligands and their complexes, we have synthesized and characterized a series of metal complexes with two structurally related ligands, 9-acridinecarboxylic acid (HL(1)) and 4-quinolinecarboxylate acid (HL(2)), [Cu(2)(mu(2)-OMe)(2)(L(1))(2)(H(2)O)(0.69)](n) 1, [Cu(2)(L(1))(4)(CH(3)OH)(2)] 2, [Cu(3)(L(1))(6)(CH(3)OH)(6)].3H(2)O 3, [Mn(3)(L(1))(6)(CH(3)OH)(6)].3H(2)O 4, [Co(3)(L(1))(6)(CH(3)OH)(6)].3H(2)O 5, [Cu(L(2))(2)](n) 6, [Mn(L(2))(2)(H(2)O)](n) 7, and [Co(L(2))(2)(H(2)O)](n) 8. 1 is a three-dimensional (3D) polymer with an interpenetrating NbO type network showing one-dimensional (1D) channels, whereas 2 and 3 take bi- and trinuclear structures, respectively, because of the differences in basicity of the reaction systems in preparing the three complexes. 4 and 5 have trinuclear structures similar to that of 3. In 1-5, ligand L(1) performs different coordination modes with N,O-bridging in 1 and O,O'-bridging in 2-5, and the metal ions also show different coordination geometries: square planar in 1, square pyramidal in 2, and octahedral in 3-5. 6 has a two-dimensional structure containing (4,4) grids in which L(2) adopts the N,O-bridging mode and the Cu(II) center takes square planar geometry. 7 and 8 are isostructural complexes showing 1D chain structures, with L(2) adopting the O,O-bridging mode. In addition, the intermolecular O-H...N hydrogen bonds and pi-pi stacking interactions further extend the complexes (except 1 and 6), forming 3D structures. The magnetic properties of 2-7 have been investigated and discussed in detail.

In Situ Generation of Carboxylate: An Efficient Strategy for a One-Pot Synthesis of Homo- and Heterometallic Polynuclear Complexes

An efficient strategy for synthesis of a wide range of homo- and heterometallic polynuclear complexes is proposed. The synthesis protocol consists of a two-step one-pot reaction. The first step is the in situ generation of carboxylate anions via oxidation of aromatic aldehydes by metal nitrates in air. The aldehydes act as solvents and are also involved in redox processes. Solutions containing solely transition metal cations and aromatic carboxylates are obtained following this procedure. The second step is a tunable "à la carte" formation of a series of various polynuclear carboxylato complexes from solutions obtained at the former stage upon addition of different solvents. The polarity and donor properties of the solvents play a key role in determination of the nuclearities of the complexes. Hydrolytic processes can induce the formation of oxo- or hydroxo-bridges inside the polynuclear core as well. Complexes of various nuclearities are obtained: from discrete tri-, hexa-, or octanuclear units to 1D polymers. This protocol can be adapted with disconcerting simplicity to the synthesis of heterometallic species with similar molecular structures to their homometallic analogues starting from stoichiometric mixture of metal nitrates under the same reaction conditions. Detailed description of synthesis and the molecular structure of one representative complex for each series are presented in this paper. The temperature dependence of magnetic susceptibility of the heterometallic 1-D MnCo chain reveals typical behavior of a ferrimagnetic chain. The low-temperature investigations on single crystals show significant Ising type magnetic anisotropy.

Structural, Magnetic, and Spectroscopic Comparative Studies on Four New Derivatives of DIMMAL (2-Di1H-2-imidazolylmethylmalonate): A Novel Generator of Multidimensional Networks

This paper reports the synthesis, structure solution, and magnetic characterization of four new DIMMAL-containing compounds (H2DIMMAL = 2-di1H-2-imidazolylmethylmalonic acid), H2DIMMAL x H2O (1), Na2(DIMMAL) x 5H2O (2), [Cu(HDIMMAL)2] (3), and [Cu2(DIMMAL)2(H2O)2] x 2H2O (4). Compound 1, containing two carboxylates and two protonated imidazole rings, adopts the dizwitterion configuration. These monohydrate MBBs pack together into a 3D array driven, as in the other three cases herein reported, by a combination of multiple-path H-bonds and aromatic-aromatic interactions. Compound 2 consists of centrosymmetric Na+ tetramers in which four NaO6 distorted octahedra are interconnected by carboxylate and water bridges. Compound 3 consists of mononuclear [Cu(HDIMMAL)2] units in which HDIMMAL- acts as a tridentate ligand through two imidazole N atoms and the deprotonated O from a carboxylate. Compound 4 consists of centrosymmetric cyclic dinuclear [Cu2(DIMMAL)2(H2O)2] x 2H2O units involving propionate-arm bridges. The building-block units described above, in each case, are interconnected into 3D networks by multiple H-bonding paths and aromatic-aromatic interactions. The EPR spectra are indicative of an essentially d(x2-y2) ground state for the copper(II) ions in 3 and 4 (CuN4O2 and CuN2O2O' chromophores, respectively). Magnetic susceptibility measurements in the range of 1.8-200 K for compound 4 show weak antiferromagnetic exchange between the copper(II) ions (2J = -1.6(1) cm(-1)). The effectiveness of the propionate-arm bridges, involving C-C sigma bonds, in propagating magnetic exchange between the copper(II) ions is discussed.