Acetate Bridged Trinuclear Zn, Ca and Mg Metal Complexes with 2- and 4-Substituted Pyridines

Abstract

The structures of the complexes [Zn 2 (C 5 H 6 N 2 ) 2 (C 2 H 3 O 2 ) 6 Ca], compound 1; [Zn(C 7 H 10 N 2 ) 2 Cl 2 ] compound 2; and [Zn 2 (C 5 H 6 N 2 ) 2 (C 2 H 3 O 2 ) 6 Mg] compound 3 were established by spectral and X-ray diffraction studies. These complexes form part of the project of design and synthesis of new alkaline-earth metal complexes with multiple applications in the fields of catalysis, material science and biochemistry. Compound 1 crystallizes in the monoclinic space group P2 1 /c with unit cell parameters a = 11.6918(11), b = 8.2850 (8), c = 15.3472(15) Å , b = 96.4140(10)°, Z = 2. Compound 2 crystallizes in the orthorhombic space group Pccn with unit cell parameters a = 13.6485(13), b = 14.2962(14), c = 18.2459(18) Å , Z = 8. Compound 3 crystallizes in the monoclinic space group P2 1 /c with unit cell parameters a = 7.5531(8), b = 22.905 (3), c = 8.7137(9) Å , Z = 2. All three structures (1-3) were solved by direct methods and refined to R = 0.0257, 0.0346 and 0.0244, respectively. For compound 1 crystallizes with the Ca 2? ion coincident with crystallographic centre of symmetry forming a dimer. The Ca 2? ion is six-fold coordinated by three acetate ligands. The Ca polyhedron may be described as a distorted tricapped trigonal prism. The Zn 2? ion is four-fold coordinated by three O atoms from three acetate groups (atoms O 2 , O 4 and O 5 ) and an N atom from the 2-aminopyridine moiety. The Zn polyhedral may be described as a distorted tetrahedral coordination. Compound 2 crystallizes as a crystallographic C 2 -symmetric complex, in which each Zn 2? ion is bound to two 4-dimethylaminopyridine units, and two Cl -1 ions. The tetracoordinated Zn atoms adopt a distorted tetrahedral geometry. Compound 3 crystallizes with the Mg 2? ion coincident with crystallographic centre of symmetry forming a dimer. The Mg 2? ion is octahedrally coordinated by six O atoms from three acetate groups. The Zn 2? ions are in a tetrahedral geometry. In the crystal structures 1 and 3, the molecules are stabilized by N-HÁÁÁÁÁÁO; C-HÁÁÁÁÁÁO interactions. However in the crystal structure 2, the molecules are stabilized by C-HÁÁÁÁÁCl interactions.

Chemical Assembling of Heterometallic {Cd–M} (M=Li, Mg, Eu, Tb) Molecules with 3,5‐Di‐tert‐butylbenzoate Bridges and N‐Donor Ligands

“…The structures of compounds III and IV are similar to the previously described trinuclear complexes of 3d metals, for example, [MM' 2 L 2 (OOCR) 6 ] (M = Mg, Ca, Sr, Ba; M' = Co II , Ni II , Zn II ; L is a chelating or monodentate N-donor ligand, such as bpy, 5,5'-dimethyl-2,2'-dipyridyl, quinoline, 6-methylquinoline, diethyl nicotinamide, 2-aminopyridine, 4-vinylpyridine; O 2 CR À is a monocarboxylate anion, such as acetate, trimethylacetate, propionate, crotonate, benzoate), [8,10,11,[20][21][22][23][24] and CdÀ Mg and CdÀ Ca designate heterometallic complexes…”

“…[1][2][3][4][5][6] The range of known compounds is also expanded by synthesizing heterometallic complexes where ions of 3d-metals and ions of alkali metals, alkaline-earth elements or lanthanides may be combined in a single molecule. [7][8][9][10][11] It is important that in many cases, the polynuclear structure of the metal moiety is preserved both upon replacement of N-donor ligands and carboxylate anions, which significantly expands the options for the chemical design of new heterometallic derivatives and allows one to manipulate the physical characteristics of molecules and even the crystals that are formed from them. [12] Cadmium(II) carboxylates, along with 3d-metal carboxylates, are attractive as a basis for the chemical design of practically important compounds.…”