[show abstract][hide abstract] ABSTRACT: A 2D layer complex 1 and a linear trinuclear complex 2 with mixed ligands have been synthesized and characterized by elemental analyses, IR and single-crystal X-ray diffraction. In 1, the Mn(II) ions are six-coordinated and lie in distorted octahedron coordination environments. Complex 1 is connected into a 2D layer structure based on a linear trinuclear Mn3(admtrz)4(N3)6 (admtrz=4-amino-3,5-dimethyl-1,2,4-triazole) building unit with either (6,3) topology when Mn1 cations as three-connected nodes or (4,4) network when the coordination trinuclear units being regarded as four connected nodes. In 2, the Co(II) ions are in slightly distorted octahedron coordination geometries. The magnetic behaviors are investigated in the temperature range 1.8–300K. The magnetic susceptibility measurements show that the Mn(II) ions of complex 1 are weakly antiferromagnetically coupled with g=1.98(1), J1=−6.31(5)cm−1 and J2=−1.88(1)cm−1. There is dominant zero field splitting (ZFS) effects with g values, g//=2.38(2) and g⊥=4.96(4), indicated a significant presence of the spin–orbit coupling and magnetization experiment reveals large, uniaxial zero-field splitting parameters of D=−29.55cm−1 for 2.
[show abstract][hide abstract] ABSTRACT: Three new coordination polymers ([Mn(3)(dctrz)(2)(H(2)O)(8)](n) (1), [Co(Hdctrz)(H(2)O)(3)](n) (2) and [Cd(Hdctrz)(H(2)O)(2)](n) (3), H(3)dctrz, 1-H-1,2,4-triazole-3,5-dicarboxylic acid) based on the self-assembly of Mn(2+), Co(2+) and Cd(2+) ions with H(3)dctrz have been synthesized and characterized by single crystal X-ray diffraction analysis. Variable temperature magnetic studies are investigated for complexes 1 and 2. Complex 1 is assembled into a one-dimensional molecular chain via trinuclear units formed from two dctrz anion bridges and eight coordination waters. In 2, the central Co(2+) cations with six-coordinated octahedron geometry are bridged by Hdctrz anions to form one-dimensional zigzag chain structures. Complex 3 displays a 2D rhombus grid-like architecture with a (4, 4) topology, achieved through Hdctrz anion bridges. Both complexes 1 and 2 exhibit S = 5/2 (Mn(2+)) and S = 3/2 (Co(2+)) spin Heisenberg chains with alternating and regular magnetic sequences. Variable temperature (1.8-300 K) magnetic studies indicate weak antiferromagnetic coupling between the metal centres in complexes 1 and 2.
[show abstract][hide abstract] ABSTRACT: Novel complexes of (half)-filled d-configurations, including [Zn(pdon)(SCN)(μ-Cl)(H2O)]n (1), [Cd2(pdon)2(μ1,3-SCN)4]n (2), [Hg(pdon)2Cl2] (3), and [Mn(pdon)2(SCN)2] (4) (pdon = 1,10-phenanthroline-5,6-dione), were synthesized and structurally characterized by single crystal X-ray diffraction. Self-assembly behaviors of these metal ions with anions are essentially different, although some of them are elements of the same group. Various supramolecular interactions of H-bonding, π···π stacking, and C−X···π (X = H, O, and S) are observed in the structures. In 1, central Zn2+ cations are connected to form an infinite one-dimensional (1D) zigzag chain by bridged Cl− and further extended to two-dimensional layers via weak interactions. Complex 2 consists of dinuclear units doubly bridged by two end-to-end (EE) SCN− anions and linked to 1D molecular helix along the b-axis with a long pitch of 13.077 Å. The helix displays racemic mixtures in the crystal. Complexes 3 and 4 are six-coordinated with distorted octahedron geometry. pdon serves as a terminal ligand in complexes. Spectroscopic and electrochemical properties of pdon and the complexes are studied in dimethyl sulfoxide (DMSO) solution at room temperature. Circular dichroism (CD) spectral results suggest that there is phenomenon of spontaneous resolution in the DMSO solution for the spiral structure 2.
[show abstract][hide abstract] ABSTRACT: In the title compound, [Mn(C(13)H(9)N(2)O)(2)(CH(3)OH)(2)]Cl, the Mn(III) atom (site symmetry ) is coordinated by two N,O-bidentate 2-(1H-benzimidazol-2-yl)phenolate ligands and two methanol mol-ecules, to generate a distorted trans-MnN(2)O(4) octa-hedral geometry for the metal ion. The dihedral angle between the aromatic ring systems in the ligand is 16.0 (3)°. In the crystal structure, the complex cations and chloride anions are linked by O-H⋯Cl and N-H⋯Cl hydrogen bonds. The chloride ion lies on a crystallographic twofold axis.
[show abstract][hide abstract] ABSTRACT: In the title compound, [Co(C(6)H(5)N(4))(3)], the Co(III) atom adopts a distorted octa-hedral CoN(6) coordination geometry, arising from three N,N'-bidentate deprotonated 2,2'-biimidazole ligands. The dihedral angles between the five-membered rings of the ligands are 4.1 (2), 9.4 (2) and 10.5 (2)°. In the crystal, mol-ecules are linked by N-H⋯N hydrogen bonds, generating a layered network lying in (11).
[show abstract][hide abstract] ABSTRACT: In the title compound, (C(5)H(7)N(2))(6)[V(10)O(28)]·2H(2)O, the [V(10)O(28)](6-) anion is generated by crystallographic inversion symmetry and each of the five vanadium centres adopts a distorted VO(6) octa-hedral geometry. In the crystal structure, a network of N-H⋯O, N-H⋯(O,O) and O-H⋯O hydrogen bonds helps to establish the packing.