Hilmi Namli

Investigations into ambient temperature biaryl coupling reactions

Abstract An ambient temperature, unsymmetrical, biaryl coupling reaction for hindered systems based on Suzuki methodology has been developed. A description of the optimisation of this process leading to the recommendation of aqueous thallium hydroxide as base, in dimethylacetamide, with hindered boronic acids and aryl halides to achieve good to moderate yields of hindered biaryls is presented, along with an interpretation of the reaction conditons. The yields of hindered Stille biaryl coupling reactions seemed to be little enhanced by the use of less coordinating ligands such as tri-2-furylphosphine and triphenylarsine.

Supramolecular lead(II) azide complex of 2,6-diacetylpyridine dihydrazone: synthesis, molecular structure, and biological activity

The complex of 2,6-diacetylpyridinedihydrazone (L) with lead(II) and azide has been characterized by elemental analyses, FTIR, and single-crystal X-ray analysis. The Pb(C9H13N11) (1) crystallized in the monoclinic space group C2/c. The coordination of 1 exhibits a gap around the lead(II), possibly occupied by a stereochemically active electron lone pair on lead(II) resulting in a hemidirected complex. Antimicrobial activity of the complex is higher than the free ligand.

Synthesis, characterization, crystal structure and thermal analysis of a copper(II) mononuclear compound with 2,6- bis (3,5-dimethyl- N -pyrazolyl)pyridine (bdmpp) and selenocyanate as ligands

A single crystal of the copper(II) compound, [Cu(bdmpp)(SeCN)2], 2, was obtained and its crystal structure was determined by X-ray diffraction methods. The complex was characterized by elemental, thermal and FTIR analysis. The FTIR analysis of the complex clearly shows the SeCN peaks at 2096 and 2061 cm−1 which did not exist in the free organic ligand (bdmpp). X-ray analysis showed that 2 crystallized in the monoclinic space group P21/c. Cu(II) has a distorted trigonal bipyramidal coordination involving three N atoms from the ligand and two N atoms from the selenocyanate group.

Detection of tautomer proportions of dimedone in solution: a new approach based on theoretical and FT-IR viewpoint

Molecular structures of stable tautomers of dimedone [5,5-dimethyl-cyclohexane-1,3-dione (1) and 3-hydroxy-5,5-dimethylcyclohex-2-enone (2)] were optimized and vibrational frequencies were calculated in five different organic solvents (dimethylsulfoxide, methanol, acetonitrile, dichloromethane and chloroform). Geometry optimizations and harmonic vibrational frequency calculations were performed at DFT 6-31+G(d,p), DFT 6-311++G(2d,2p), MP2 6-311++G (2d,2p) and MP2 aug-cc-pVDZ levels for both stable forms of dimedone. Experimental FT-IR spectra of dimedone have also been recorded in the same solvents. A new approach was developed in order to determine tautomers’ ratio using both experimental and theoretical data in Lambert–Beer equation. Obtained results were compared with experimental results published in literature. It has been concluded that while DFT 6-31+G(d,p) method provides accurate enol ratio in DMSO, MeOH, and DCM, in order to obtain accurate results for the other solvents the MP2 aug-cc-pVDZ level calculations should be used for CH3CN and CHCl3 solutions.

Modeling the intermolecular interactions: molecular structure of N-3-hydroxyphenyl-4-methoxybenzamide.

The title compound, N-3-hydroxyphenyl-4-methoxybenzamide (3) was prepared by the acylation reaction of 3-aminophenol (1) and 4-metoxybenzoylchloride (2) in THF and characterized by ¹H NMR, ¹³C NMR and elemental analysis. Molecular structure of the crystal was determined by single crystal X-ray diffraction and DFT calculations. 3 crystallizes in monoclinic P2₁/c space group. The influence of intermolecular interactions (dimerization and crystal packing) on molecular geometry has been evaluated by calculations performed for three different models; monomer (3), dimer (4) and dimer with added unit cell contacts (5). Molecular structure of 3, 4 and 5 was optimized by applying B3LYP method with 6-31G+(d,p) basis set in gas phase and compared with X-ray crystallographic data including bond lengths, bond angles and selected dihedral angles. It has been concluded that although the crystal packing and dimerization have a minor effect on bond lengths and angles, however, these interactions are important for the dihedral angles and the rotational conformation of aromatic rings.

Characterization, adsorption, and electrokinetic properties of modified sepiolite

AbstractThe metal ion adsorption and electrokinetic properties of sepiolite modified by 3-(trimetoxysilyl)propyl metaacrylate was studied. The characterization of modified sepiolite was made by Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), scanning electron micrograph (SEM), and differential thermal analysis/thermogravimetry (DTA/TG). The adsorption behavior of Fe(III), Mn(II), Co(II), Zn(II), Cu(II), and Cd(II) metal ions on modified sepiolite from aqueous solutions was investigated as a function of equilibrium pH, temperature, and ionic strength. The adsorption experiments were carried out using a batch method. The initial and final concentrations of heavy metals were determined by means of atomic absorption spectrophotometry. The zeta potential of the modified sepiolite suspensions was measured as a function of metal ion concentration and equilibrium pH using a Zeta Meter 3.0. The results showed that the amount of adsorbed metal ions increased with solution pH, and tha...

Hemidirected novel lead(II) azide complex of 2,6-diacetylpyridine dihydrazone

1 related problem, the field of Molecular Magnetism is currently shifting towards more complicated systems. One direction has been opened by the observation of slow relaxation of the magnetization in 1D systems (called Single Chain Magnets or SCMs). Synthetic efforts are devoted to the development of new systems SCMs that can help us understanding the physical background that lies beneath this phenomenon. In this contest several groups have development new tools allowing for the engineering of both magnetic and structural properties. Here we discuss some opportunities offered by the Metal Nitronilnitroxyde strategy. In particular the experimental and theoretical work developed on finite-size effects revealed itself a key point. We describe the rational strategy that allowed creating the first rare-earth based SCMs. We show that we can freely substitute the metallic centres without structural alterations, thus tuning of the magnetic properties. This affords a useful information on the key parameters that rule SCMs.