Sefa Durmus

Some new NiZn heterodinuclear complexes: square-pyramidal nickel(II) coordination

A new series of heterodinuclear nickel(II)zinc(II) complexes, [NiL·ZnCl 2 ·4-picoline] ( 1 ), [NiLDM·ZnCl 2 ·4-picoline] ( 2 ), [NiL·ZnBr 2 ·4-picoline] ( 3 ), [NiLDM·ZnBr 2 ·4-picoline] ( 4 ), [NiLDM·ZnBr 2 ·3-picoline] ( 5 ), [NiLDM·ZnBr 2 ·3,5-lutidine] ( 6 ) and [NiL·ZnI 2 ·4-picoline] ( 7 ), where L is N , N ′-bis(salicylidene)-1,3-diaminopropane dianion and LDM is N , N ′-bis(salicylidene)-2,2′-dimethyl-1,3-diaminopropane dianion, were prepared. The complexes were characterized by elemental analysis, thermogravimetric analysis and IR spectroscopy. X-ray crystallographic analysis of complexes 1 , 2 and 4 revealed that nickel(II) ion in heteronuclear complexes had a square-pyramidal coordination sphere. It is concluded that formation of square-pyramidal nickel(II) coordination depends strongly on the concentration of methyl pyridine present in the medium and occurs when methyl pyridine/Ni ratio is below 1.5.

INVESTIGATIONS ON SOME HETERO-TRINUCLEAR COMPLEXES OF NICKEL(II) AND COPPER(II)

Ni(II) and Cu(II) complexes of N,N′-bis(salicylidene-1,3-diaminopropane) were prepared and found to form linear and non-linear trinuclear complexes. Elemental analyses, IR spectroscopy, thermogravimetry and X-ray diffraction techniques applied to the complexes yielded valuable information about their moleculer structures. It was observed that μ-bridges in these trinuclear complexes form through the phenolic oxygens of the ligand or through anions present in the medium. In the presence of acetate, nitrate or nitrite, μ-bridges form between a pair of atoms resulting in linear trinuclear complexes. However, the presence of chloride or bromide results in μ-bridges involving the phenolic oxygens of N,N′-Bis(salicylidene)-1,3-diaminopropane.

Synthesis and crystal structure of a homotrinuclear Ni(II) complex

Abstract A tetradentate ONNO type Schiff base was synthesized from salicyaldehyde and 1,4-diaminobutane. Thermogravimetric analysis, elemental analysis and X-ray diffraction results showed this Schiff base to give a trinuclear complex with Ni(II) ions in presence of acetate ions. The complex crystallizes in the triclinic P-1 space group with a = 9.7510(2), b = 10.6854(2), c = 12.4781(4) Å, α = 112.101(3), β = 100.621(4) and γ = 91.733(3)°. Similar to those found in the literature the terminal Ni(II) ions are coordinated to the Schiff base and have a N2O4 coordination sphere. The central Ni(II) ion has a O6 coordination sphere formed by the phenolic oxygens and the acetate bridges. The conformation of the chelate ring formed between the Ni(II) ions and the iminic nitrogens were examined.

Crystal structure and thermal analysis of new mononuclear nickel (II) complexes with NNN type pyrazolyl ligands and halids

Abstract Mononuclear Ni(II) complexes of Bis-2,6(pyrazolyl)pyridine(pp), 2(1-pyrazolyl)-6-(3,5-dimethylpyrazol-1-yl)pyridine(mpp) and bis-2,6(3,5-dimethyl-pyrazolyl-1yl)pyridine(dmpp) were prepared in MeOH : H2O mixtures. The complexes were characterized using elemental analysis, IR spectroscopy, X-ray diffraction and thermal analysis. The molecular structure of [Nidmpp(H2O)2Br]Br was evaluated and the Ni(II) ion was found to be in a distorted octahedral coordination environment. One of the halogen ions was found to coordinate the Ni(II) ion whereas the other ion does not coordinate and forms hydrogen bonds with the water molecules situated on the neighboring complex molecules, resulting in a supramolecular arrangement. Thermogravimetric results showed three coordinated water molecules in the pp and mpp complexes. Conductometric and potentiometric studies of the complexes showed 2 and 1 turning points, respectively.

Two new mononuclear Ni(II) complexes with reduced ONNO type Schiff base

Abstract N,N′-bis(salicylidene)-1,3-propanediamine (LH2) and N,N′-bis(salicylidene)-2,2′-dimethyl-1,3-propanediamine (DMLH2) were reduced to phenolic amines by using NaBH4. Mononuclear complexes were obtained with Ni (II) in a N3O6 coordination sphere with these amines and N3– ions, in DMF media. It was established with the XRD studies that the coordination spheres were distorted octahedral and the complex obtained with LH2 formed dimeric structures via phenolic OH bonds. The other complex was seen to have monomeric structure. The complexes were characterized by X-ray diffraction, elemental analysis, termogravimetry, IR spectroscopy and simple magnetic susceptibility (Gouy method). In addition, cyclic voltammetric studies have been performed.

Electrochemical behaviour of 3,8-difluorobenzo[c]cinnoline at mercury electrode

Voltametric and coulometric methods have been used to study the electroanalytical behaviour of 3,8-difluorobenzo[c]cinnoline. The number of electrons transferred, the wave characteristics, diffusion coefficient and reversibility of the reactions have been investigated in ethyl alcohol-BR. Adsorption of the molecule on the surface of the mercury drop electrode was analyzed and this phenomena was exploited to calculate the diffusion coefficient of 3,8-difluorobenzo[c]cinnoline. A mechanism for the electrode reaction was proposed.

Synthesis and DFT study of Cd(II) and Hg(II) complexes of ONNO-type Schiff bases

ABSTRACT This study consists of the synthesis of cadmium (II) and mercury (II) metal complexes of ONNO-type Schiff bases. Two different ONNO-type Schiff bases were prepared. One cadmium(II) and one mercury(II) complex of the considered Schiff bases were achieved. Both are proved to be mononuclear complexes. Ligands and complexes were analyzed via melting point determination, elemental analyses, thermogravimetric (TG) analysis, infrared (IR) spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. Moreover, structural and energetic analyses for both complexes have been realized using Hartree-Fock (HF) and density functional theory (DFT) methods with CEP-121G basis set.