Vol 45, No 7 (2019)

Coordination compounds of nickel(II) and copper(II) 1,5-naphthalenedisulfonates with nicotinamides, [Ni(L)₂(H₂O)₄](Nds) · 3H₂O (I) and [Cu(L)₂(H₂O)₄](Nds) (II) (L = nicotinamide, NC₅H₄C(O)NH₂, Nds² = doubly deprotonated 1,5-naphthaledisulfonate anion, \({{{\text{C}}}_{{{\text{1}}0}}}{{{\text{H}}}_{{\text{6}}}}({\text{S}}{{{\text{O}}}_{{\text{3}}}})_{{\text{2}}}^{{{\text{2}}-}}\)), were synthesized and studied by IR and diffuse reflectance spectroscopy. The crystal structures of I and II were determined by X-ray diffraction (CIF files CCDC nos. 1863367 (I) and 1863368 (II)). In both structures, the Ni and Cu atoms are coordinated by two nitrogen atoms of two monodentate L ligands and by four oxygen atoms of water molecules. The coordination polyhedron of Ni in I is a slightly distorted octahedron and that of Cu in II is a tetragonal (4 + 2) bipyramid extended due to the Jahn–Teller effect, with the O(H₂O) atoms in the axial positions. The [M(L)₂(H₂O)₄]²⁺ complex cations, the Nds^2– anions, and water molecules of crystallization in II are combined by a branched network of hydrogen bonds.

The heterospin copper(II) complex, ((pyridin-2-ylmethylene)-4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl)-3,6-di-tert-butylcatecholatocopper(II) (I), is synthesized and characterized by IR spectroscopy, magnetochemistry, EPR, and X-ray diffraction analysis. The one-electron oxidation of complex I by AgBF₄ affords the biradical copper(I) complex: bis[((pyridin-2-ylmethylene)-4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl)]copper(I) (II). An analysis of the parameters of isotropic EPR spectra of complexes I and II indicates that they are biradicals with the fast (I) and intermediate (II) exchange interaction between the radical centers.

Complexes [Zn(L)Cl₂] (I), Cu(L)Cl₂ ∙ H₂O (II), Zn(L¹)Cl₂ ∙ 0.5H₂O (III), and Cu(L¹)Cl₂ ∙ 0.5H₂O (IV) (where L and L¹ are the diaminopropylene and diaminoethylene derivatives of deoxycholic acid, respectively) are synthesized. The structure of mononuclear complex I is determined by X-ray structure analysis (CIF file CCDC no. 1875305). The coordination polyhedron of the Zn atom (Cl₂N₂) is a distorted tetrahedron. According to the X-ray diffraction data, the crystals of compounds III and IV are isostructural. It is shown by IR spectroscopy that the structures of complexes II–IV are similar to that of complex I. In the solid phase, compounds L and L¹ possess photoluminescence in the visible spectral range (λ_max = 440 and 415 nm, respectively). Complex formation with Zn²⁺ ions does not change the photoluminescence properties of L and L¹.

Two new coordination polymers {[Zn(HL)(HBpp)] · H₂O}_n (I) and [Cd(HL)(HBpe)]_n (II) (H₄L = 5-(2,3-dicarboxy phenoxy) isophthalic acid, Bpp = 1,3-bis(4-pyridyl)propane, Bpe = 1,2-bis(4-pyridyl)ethylene) were prepared and characterize by element analysis, powder XRD and single crystal X-ray diffraction (CCDC nos. 1836060 (I), 1844999 (II)). The single-crystal X-ray diffractions reveal that the complex I is a 2D carboxylate layer with the HBpp suspension arms, in which the zinc(II) is four-coordinated with a tetrahedral geometry. Compound II is a 1D Cd(II)-carboxylate chains, in which the cadmium(II) is seven-coordinated with a distorted pentagonal bipyramidal geometry. Complexes I and II are further extended into three-dimensional supramolecular framework via hydrogen bonds. The solid state luminescent properties of compounds I and II have been investigated.

Two new dioxomolybdenum(VI) complexes, [MoO₂L(EtOH)] (I) and [MoO₂L(Sal)] (II), where L is the dianionic form of 4-chloro-2-{[4-(diethylamino)-2-hydroxybenzylidene]amino}phenol (H₂L), Sal is 4-diethylaminosalicylaldehyde, were prepared and characterized by IR and UV-Vis spectra, as well as single crystal X-ray diffraction (CIF files CCDC nos. 1849408 (I) and 1849409 (II)). Complex I crystallizes as the triclinic space group \(P\bar {1}\) with unit cell dimensions a = 7.3050(10), b = 11.6969(16), c = 13.3433(19) Å, α = 103.915(2)°, β = 102.542(2)°, γ = 105.676(2)°, V = 1015.8(2) ų, Z = 2, R₁ = 0.0616, wR₂ = 0.1579, GOOF = 1.080. Complex II crystallizes as the triclinic space group \(P\bar {1}\) with unit cell dimensions a = 7.0773(11), b = 12.8817(12), c = 16.420(2) Å, α = 107.000(2)°, β = 101.478(2)°, γ = 91.416(2)°, V = 1397.4(3) ų, Z = 2, R₁ = 0.0484, wR₂ = 0.1048, GOOF = 1.015. X-ray analyses indicate that the complexes are dioxomolybdenum(VI) species with the Mo atoms in octahedral coordination. The catalytic oxidation property of the complexes with tert-butylhydroperoxide in CH₂Cl₂ was studied.