Okan Zafer Yeşilel

Spectroscopic characterization of charge-transfer complexes of morpholine with chloranilic and picric acids in organic media: crystal structure of bis(morpholinium 2,4,6-trinitrocyclohexanolate).

Electron donor-acceptor interaction of morpholine (morp) with chloranilic acid (cla) and picric acid (pa) as pi-acceptors was investigated spectrophotometrically and found to form stable charge-transfer (CT) complexes (n-pi*) of [(Hmorp)(2)(cla)] and [(Hmorp)(pa)](2). The donor site involved in CT interaction is morpholine nitrogen. These complexes are easily synthesized from the reaction of morp with cla and pa within MeOH and CHCl(3) solvents, respectively. (1)HNMR, IR, elemental analyses, and UV-vis techniques characterize the two morpholinium charge-transfer complexes. Benesi-Hildebrand and its modification methods were applied to the determination of association constant (K), molar extinction coefficient (epsilon). The X-ray crystal structure was carried out for the interpretation the predict structure of the [(Hmorp)(pa)](2) complex.

Synthesis, spectroscopy, thermal behaviour and molecular structure of orotatotriethanolaminecopper(II) monohydrate

Abstract The orotatotriethanolaminecopper(II) monohydrate, [Cu(C5H2N2O4)(C6H15NO3)] · H2O, has been synthesized and characterized with physico-chemical methods (IR and UV-Vis spectroscopy, magnetic susceptibility, conductivity and thermoanalytical measurements) and X-ray diffraction. The structure derived from physico-chemical methods is consistent with that of the X-ray diffraction. The compound crystallizes in the monoclinic system, space group P21/n, with a = 8.6282(12), b = 16.9919(18), c = 10.6985(15) Å, β = 110.08(3)°, V = 1473.1(3) Å3, Z = 4. The copper atom is chelated by the deprotonated nitrogen pyrimidine atom and by the carboxylate oxygen atom of the orotate dianion ligand, and by the nitrogen and oxygen atoms of the triethanolamine ligand. The title compound has a distorted octahedral coordination geometry.

An unusual 3D metal–organic framework, {[Ag4(μ4-pzdc)2(μ-en)2]·H2O}n: C–H⋯Ag, N–H⋯Ag and (O–H)⋯Ag interactions and an unprecedented coordination mode for pyrazine-2,3-dicarboxylate

A novel three-dimensional (3D) metal–organic framework of silver(I)-pyrazine-2,3-dicarboxylate (pzdc) with ethylenediamine ligand (en), {[Ag4(μ4-pzdc)2(μ-en)2]·H2O}n (1), was synthesized and structurally characterized by spectral methods (FT-IR and photoluminescence), elemental analysis, thermal analysis (TG, DTG, DTA) and single crystal X-ray diffraction techniques. X-ray crystallographic study of 1 revealed that the pzdc ligand adopts a new coordination mode. Four Ag(I) atoms with different coordination geometries are linked together with carboxylate groups to form 1D tetranuclear building block. The adjacent 1D blocks are connected through the en ligand to form a 2D layer structure, which is further connected to a 3D framework by argentophilic interaction (Ag1⋯Ag2 = 3.096 and Ag3⋯Ag4 = 3.3070 A). The complex exhibits C–H⋯Ag, N–H⋯Ag intermolecular multicenter heteroacceptor (IMH) hydrogen-bonding interactions between the Ag(I) ions and hydrogen atoms of the en ligand and (O–H)⋯Ag interaction of the pseudo-agostic (IPA) between the Ag(I) ion and hydrogen atoms of the water molecule. In order to assess the potential of 1 in gas storage applications, we performed atomically detailed simulations. Furthermore, 1 exhibits green and unusual yellow luminescence in the solid state at room temperature. Complex 1 has also good antimicrobial activity (36–63 μg mL−1) on studied microorganisms.

Chelate ring stacking interactions in the supramolecular assemblies of Zn(II)and Cd(II) coordination compounds: a combined experimental and theoretical study

The self-assembly of Zn(II) and Cd(II) ions with two isomeric tetradentate ligands, 2-pyridyl-isonicotinoylhydrazone (HL1) and 2-benzoylpyridyl-picolinoylhydrazone (HL2), was studied by elemental analysis, FT-IR spectroscopy and single-crystal X-ray diffraction. The reaction of zinc(II) and cadmium(II) salts with HL1 and HL2 in methanol under solvothermal conditions produced six monomer and one tetranuclear zinc(II) complexes, namely, Zn(HL1)Br2 (1), Zn(HL1)Cl2 (2), [Cd(HL1)2](NO3)2·H2O (3), Cd(HL2)Br2(4), Zn(HL2)Cl2 (5), Zn(HL2)Br2 (6) and [Zn4(L2)4I2][ZnI4]·2H2O (7). The structure of 7 includes a cationic tetranuclear cluster of four zinc ions, four ligands, and two anions, counterbalanced by ZnI42− ions. However, the reaction of zinc(II) and cadmium(II) salts with HL1 under the same conditions produced monomer compounds. Herein, the ligand effects on the complex structures were studied. Hirshfeld surface analysis and fingerprint plots facilitate the comparison of intermolecular interactions in compounds 1–7, which are crucial in building supramolecular architectures.

Synthesis and crystal structure of cyano-bridged three dimensional polyheteronuclear complex

Abstract The cyano-bridged 3D heteronuclear polymeric complex, [Cd(NH3)(μ-ampy)Ni(μ-CN)4]n, (1) (ampy = 3-aminomethylpyridine), has been synthesized and characterized by FT-IR and Raman spectral, thermal and elemental analyses. The crystal structure of 1 has been determined by X-ray single crystal diffraction. The complex crystallizes in orthorhombic system with space group Pnma. In 1, Ni(II) ion is five coordinated with square-pyramidal geometry defined by the four C atoms from the four symmetry related cyano ligands and one N atom from the ampy ligand. The Cd(II) ion adopts slightly distorted octahedral coordination geometry completed by the six N atoms from one ammine, one ampy and four cyano ligands. The [Ni(CN)4]2– anion is coordinated to the adjacent four Cd(II) ions to generate a Cd—Ni(CN)4 2D undulate layer. The adjacent 2D layers are connected by the μ-ampy bridging ligands to form a 3D pillar-layered framework.

Synthesis, characterization, crystal structure and biological activities of supramolecular compounds of Mn(II) and Zn(II) with dipicolinic acid and 8-hydroxyquinoline

Two compounds, (8-H2Q)2[Mn(dipic)2] · 6H2O (1) and (8-H2Q)2[Zn(dipic)2] · 6H2O (2) (8-HQ = 8-hydroxyquinoline (oxine), H2dipic = dipicolinic acid), have been prepared and characterized by elemental, spectroscopic (IR and UV–Vis), and thermal analyses, magnetic measurements and single crystal X-ray diffraction techniques. Compounds 1 and 2 consist of two 8-hydroxyquinolinium cations, one bis(dipicolinato)M(II) anion (M = Mn(II) and Zn(II)) and six uncoordinated water molecules. Both 1 and 2 crystallize in the monoclinic space group C2/c. In the complex anion, each dipic ligand is tridentate through N of pyridine and oxygens of the carboxylate groups. Crystal packing of 1 and 2 is a composite of intermolecular hydrogen bonding interactions. The in vitro antibacterial and antifungal activities of 1 and 2 were evaluated by the agar well diffusion method by MIC (Minimal Inhibition Concentration), looking for compounds which display high-inhibitory effect against gram positive bacteria and fungi. No growth inhibition was observed against tested gram negative bacteria.

Spectroscopic and Thermal Studies of bis(N,N′‐Dimethylethylenediamine) and bis(N,N‐Dimethylethylenediamine)saccharinato Complexes of Co(II), Ni(II), and Cu(II)

The mixed‐ligand saccharin (Hsac) complexes of Co(II), Ni(II) and Cu(II) with N,N′‐dimethylethylenediamine (dmen), and N,N‐dimethylethylenediamine (ndmen) (Figure 1) were synthesized and characterized by elemental analysis, magnetic susceptibility, spectral (UV‐Vis and FT‐IR) methods, and simultaneous TG, DTG and DTA techniques. The complexes have pseudooctahedral geometries with two dimethylethylenediamine molecules coordinated to the metal ions as chelating ligands through their two nitrogen atoms and two monodentate saccharinato ligands in the trans positions for the complexes of the type [M(sac–O)2(dmen)2] (M = Co(II), Ni(II)), and [M(sac–N)2(ndmen)2] (M = Co(II), Ni(II), Cu(II)) and two aqua ligands in the trans positions in [Cu(H2O)2(dmen)2](sac)2. (sac–O; sac‐N = the saccharinato ligand may be coordinated to the metal ions through their carbonyl oxygen or their nitrogen atom, respectively). The decomposition mechanism and thermal stability of the solid complexes are interpreted in terms of their structures. The thermal stability order of the investigated complexes is Cu(II) > Co(II) > Ni(II) while the bis(N,N′,‐dimethylethylenediamine) complexes are thermally less stable than those of bis(N,N‐dimethylethylenediamine). The final decomposition products—the respective metal oxides—were identified by FT‐IR spectroscopy.

Picolinamidium squarate and di-p-toluidinium squarate dihydrate.

The crystal structure determinations of picolinamidium squarate, C 6 H 7 N 2 O + .C 4 O 4 - , (I), and di-p-toluidinium squarate dihydrate, 2C 7 H 10 N + .C 4 O 4 2 - .2H 2 O, (II), are reported. While salt formation occurs by donation of one H atom from squaric acid to the picolinamide molecule in (I), in compound (II), each squaric acid molecule donates one H atom to the p-toluidine N atom of two trans p-toluidine molecules. In (I), the pyridine ring is coplanar with the squarate monoanion through imposed crystallographic mirror symmetry; in (II), the dihedral angle between the p-toluidine moiety and the squarate dianion is 70.71(1)°. In (I), a three-dimensional structure is formed via van der Waals interactions between parallel planes of molecules, with hydrogen-bond interactions (N-H...O and O-H...O) acting within the planes; hydrogen bonds form a three-dimensional network in (II).

Two dimensional cyano-bridged heteropolynuclear complex containing Pd ···π interactions

Abstract The heteronuclear complex, [Cd(NH3)2(μ-ampy)Pd(μ-CN)2(CN)2]n (1) (ampy = 4-aminomethylpyridine), was synthesized and characterized by vibrational (FT-IR and Raman) spectroscopy, elemental and thermal analyses and single crystal X-ray diffraction techniques. The complex crystallizes in the triclinic system, space group P-1. The Cd(II) ion exhibits a distorted octahedral coordination by two different N-atoms from two symmetrically equivalent ampy ligands, two ammine ligands and two bridging cyano groups, whereas the Pd(II) ion has square planar coordination and is coordinated by four cyano ligands. The tetracyanopalladate(II) anion is coordinated to the adjacent two Cd(II) ions to generate a one-dimensional chain. The adjacent 1D chains are connected by the μ-ampy bridging ligands to form a 2D network. The 2D layers are further linked by Pd···π and hydrogen bonding interactions to generate a 3D supramolecular network. The decomposition reaction takes places in the temperature range of 40–900 °C in the static air atmosphere.

Supramolecular architectures of cadmium(II)-orotate complexes containing water clusters

Three novel cadmium(II) complexes containing orotate ligand have been synthesized under different pH and characterized by X-ray crystallography, IR spectroscopy and thermal analyses measurements. In the complexes, the orotate ligand exhibits three different coordination modes. In [Cd2(μ-HOr)2(H2O)4(NH3)2]·2H2O (1), the orotate acts as a tridentate ligand, showing unprecedented coordination mode. The (NH4)2[Cd3(μ-HOr)2(HOr)2(H2O)8]·4H2O (2) is constructed from orotate acting as both bidentate and tridentate bridging ligands. The Cd1 and Cd2 ions have two different coordination environments with four HOr, eight aqua ligands. Furthermore, 2 exhibits the novel 2D metal–water cluster layers. The (Hcha)4[Cd(HOr)2(H2O)(cha)][Cd(HOr)2(H2O)2]·H2O (3) (cha = cyclohexylamine, H3Or = orotic acid) consists of discrete cis and trans anionic complexes. The cha molecules exhibit chemically different functions by coordinating to Cd(II) ion in one form and being protonated and acting as counter–ions in other form. In the complexes, the supramolecular networks are constructed by novel N–H⋯O strong hydrogen bonds to form DA:AD motif, CO⋯π and π⋯π interactions.