Hakan Dal

Synthesis, characterization, tautomerism and theoretical study of some new Schiff base derivatives

New Schiff base derivatives were prepared by the condensation of 5-chloro and 5-bromo salicylaldehyde with bis(o-aminophenol)ethers. Five bis(o-nitrophenol)ether compounds were synthesized using some ditosylate, 1,3-dibromopropane and 1,4-dibromobuthane with o-nitrophenol. These compounds were reduced to bis(o-aminophenol)ethers. The products have been characterized by elemental analysis, FTIR, 1H, 13C NMR, HETCOR and HMBC spectroscopic techniques. The tautomerisms of all of the Schiff bases compounds were determined in DMSO, CHCl3, C2H5OH and C6H12 solvents and in both acidic and basic media using the UV-vis spectrophotometric method. The heat of formation (ΔHf), enthalpy (ΔH), entropy (ΔS), Gibbs free energy (ΔGf and ΔG), stable isomers, conformations and tautomers of the synthesized compounds are calculated using the MOPAC2009 (PM6) program.

Bis(isonicotinamide-κN1)bis­[4-(methyl­amino)benzoato]zinc(II) monohydrate

In the title ZnII complex, [Zn(C8H8NO2)2(C6H6N2O)2]·H2O, the Zn atom is coordinated by two 4-methylaminobenzoate (MAB) and two isonicotinamide (INA) ligands in a distorted trigonal-bipyramidal geometry; one of the MAB ions acts as a bidentate ligand while the other MAB and the two INA are monodentate ligands. The dihedral angles between the carboxyl groups and the adjacent benzene rings are 8.52 (22) and 5.10 (14)°. In the crystal, intermolecular O—H⋯O and N—H⋯O hydrogen bonding links the molecules into a supramolecular structure. Weak intermolecular C—H⋯O interactions are also present.

Phosphorus-nitrogen compounds. Part 23: syntheses, structural investigations, biological activities, and DNA interactions of new N/O spirocyclotriphosphazenes.

The Schiff base compounds (1 and 2) are synthesized by the condensation reactions of 2-furan-2-yl-methylamine with 2-hydroxy-3-methoxy- and 2-hydroxy-5-methoxy-benzaldehydes and reduced with NaBH(4) to give the new N/O-donor-type ligands (3 and 4). The monospirocyclotriphosphazenes containing 1,3,2-oxazaphosphorine rings (5 and 6) are prepared from the reactions of N(3)P(3)Cl(6) with 3 and 4, respectively. The reactions of 5 and 6 with excess pyrrolidine, morpholine, and 1,4-dioxa-8-azaspiro [4,5] decane (DASD) produce tetrapyrrolidino (5a and 6a), morpholino (5b and 6b), and 1,4-dioxa-8-azaspiro [4,5] deca (5c and 6c) spirocyclotriphosphazenes. The structural investigations of the compounds are examined by (1)H, (13)C, (31)P NMR, DEPT, HSQC, and HMBC techniques. The solid-state structures of 5, 5a, and 6 are determined using X-ray crystallography. The compounds 5a, 5b, 5c, 6a, 6b, and 6c are subjected to antimicrobial activity against six patojen bacteria and two yeast strains. In addition, interactions between these compounds and pBR322 plasmid DNA are presented by agarose gel electrophoresis.

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.

The synthesis, characterization, antimicrobial and antimutagenic activities of hydroxyphenylimino ligands and their metal complexes of usnic acid isolated from Usnea longissima

Novel multifunctional hydroxyphenylimino ligands (L1, L2 and L3) were synthesized by the condensation of 2-aminophenol, 3-aminophenol and 4-aminophenol with usnic acid, a lichen metabolite. The synthesized ligands and their Cu(II), Co(II), Ni(II) and Mn(II) complexes were characterized using FT-IR, UV-Vis, (1)H-NMR, (13)C-NMR, 1D- and 2D NMR (DEPT, COSY, HMQC and HMBC), LC-MS and TGA. In addition, the metal complexes of the novel ligands were prepared with high yields using Cu(II), Co(II), Ni(II) and Mn(II) salts and were characterized using the FT-MIR/FAR, UV-Vis, elemental analysis, ICP-OES and TG/DTA techniques. The ligands and their complexes were tested against ten important pathogen microorganisms using the disc diffusion method and the metal complexes of the ligands were more active against all of the microorganisms tested with a broad spectrum than the ligands exhibiting 11–32 mm inhibition zones. On the other hand, a broad spectrum of the strongest antimicrobial activity was determined for the Mn(II) and Cu(II) complexes of the hydroxyphenylimino ligand with usnic acid (L3). In addition, the antimutagenic activities of all of the ligands and their metal complexes were determined using the Ames-Salmonella and E. coli WP2 microbial assay systems and they showed varied and strong antimutagenic effects. In general, it has been found that the Co and Mn complexes of the ligands possess potent antimutagenic activity. In view of these results, it can be concluded that some metal complexes can be used as antimicrobial and anticancer agents.

Synthesis, crystal structure and ab initio/DFT calculations of a derivative of dithiophosphonates

The compound 2 has been synthesized from the reaction of 2,4-Bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulfide and (R)-1-[3,5-Bis(trifloromethyl)phenyl]ethanol in toluene. The obtained crude dithiophosphonic acid 1 has been treated with the excess of N(C2H5)3 to give rise to 2, [(+HN(C2H5)3][O-CH3CH-C6H3(CF3)2)(CH3OC6H4)PS2(-)]. The compound 2 has been characterized by using the spectroscopic methods such as IR, (1)H, (13)C, (31)P NMR and structural analysing method such as X-ray crystallography. It crystallizes in the orthorhombic system, whose space group is P212121. It consists of a dithiophosphonate bridged methoxyphenyl and bis(triflorophenylethyl) groups and a triethylammonium moiety linked by N-H⋯S and C-H⋯F hydrogen bonds. In the crystal structure, the C17H14F6O2PS2 molecule is elongated along the b-axis and stacked along the a-axis. The triethylammonium, N(CH2CH3)3, molecule fill in the cavities between the C17H14F6O2PS2 molecule. Moreover, ab initio methods based on Hartree-Fock (HF) and Density Functional Theory (DFT) calculations with the basis set of 6-31G(d) are also carried out to determine the molecular structural properties and to calculate FT-IR and NMR spectrum of the compound 2. The experimental results and theoretical calculations have been compared, and they are found to be in good agreement.

Synthesis and characterization of a proton transfer salt between 2,6-pyridinedicarboxylic acid and 2-aminobenzothiazole, and its complexes and their inhibition studies on carbonic anhydrase isoenzymes

Abstract A novel proton transfer compound (HABT)+(Hdipic)− (1) obtained from ABT and H2dipic and its metal complexes (2–5) have been prepared and characterized by spectroscopic techniques. Single crystal X-ray diffraction method has also been applied to 2 and 5. While complex 2 has a distorted octahedral conformation, 5 exhibits a distorted square pyramidal structure. The structures of 3 and 4 might be proposed as octahedral according to experimental data. All compounds were also evaluated for their in vitro inhibition effects on hCA I and II for their hydratase and esterase activities. Although there is no inhibition for hydratase activities, all compounds have inhibited the esterase activities of hCA I and II. The comparison of the inhibition studies of 1–5 to parent compounds indicates that 1–5 have superior inhibitory effects. The inhibition effects of 2–5 are also compared to inhibitory properties of the metal complexes of ABT and H2dipic, revealing an improved transfection profile.

Diaqua­bis[4-(dimethyl­amino)­benzoato]-κ2O,O′;κO-(isonicotinamide-κN1)cobalt(II)

The title CoII complex, [Co(C9H10NO2)2(C6H6N2O)(H2O)2], contains two 4-dimethylaminobenzoate (DMAB) anions, one isonicotinamide (INA) ligand and two coordinated water molecules. One of the DMAB anions acts as a bidentate ligand, while the other is monodentate. The four O atoms in the equatorial plane around the Co atom form a highly distorted square-planar arrangement, while the distorted octahedral coordination geometry is completed by the N atom of the INA ligand and the O atom of the second water molecule in the axial positions. An intramolecular O—H⋯O hydrogen bond between the monodentate-coordinated carboxyl group and a coordinated water molecule results in a six-membered ring with an envelope conformation. The dihedral angles between the carboxyl groups and the adjacent benzene rings are 4.29 (10)° for the monodentate ligand and 2.31 (13)° for the bidentate ligand, while the two benzene rings are oriented at a dihedral angle of 65.02 (5)°. The dihedral angles between the pyridine and benzene rings are 11.21 (5)° for the monodentate ligand and 74.60 (5)° for the bidentate ligand. In the crystal structure, intermolecular O—H⋯O, O—H⋯N and N—H⋯O hydrogen bonds link the molecules into a supramolecular structure.

Construction of homo- and heterometallic-pyridine-2,3-dicarboxylate metallosupramolecular networks with structural diversity: 1D T5(2) water tape and unexpected coordination mode of pyridine-2,3-dicarboxylate

Five new homo and heterometallic Cu(II), Cd(II), Cu(II)–Ag(I), Cu(II)–Cd(II) supramolecular networks with pyridine-2,3-dicarboxylate (pydc), {[Cu(μ-pydc)(dmpen)2]}n (1), [Cu2(μ-pydc)2(emim)4]·2H2O (2), [Cd(μ-pydc)(emim)2]n (3), [Cu(en)2(H2O)2][Ag2(pydc)2(μ-en)]·6H2O (4) and {[Cd(H2O)4Cu(μ-pydc)2]·2H2O}n (5) have been synthesized and structurally characterized (en = ethylenediamine, dmpen = 1,3-diamino-2,2-dimethylpropane and emim = 2-ethyl-4-methyl-imidazole). Owing to diverse binding modes and conformations of the pydc ligand and the different diamine or imidazole-containing coligands, these complexes exhibit structural and dimensional diversity. Complex 1 exhibits a new unexpected coordination mode of pydc, which is known as a chelating ligand, leading to the formation of a 1D coordination polymer. Complex 2 is the first dinuclear copper(II)–pydc complex containing a dinuclear metalloligand. Complex 3 is a one dimensional coordination polymer and the Cd(II) ion is six-coordinated in a distorted octahedral geometry. Complex 4 is the first 3d–4d heterometallic complex and shows two different coordination behaviors of the ethylenediamine ligand: common chelate mode and rare bridging mode. The most striking feature of 4 is the existence of a infinite T5(2) water tape. Complex 5 is the first 3d–4d heteropolynuclear complex obtained from a polynuclear metalloligand. Neighboring metalloligand double-chains bind to Cd(II) ions to form a two dimensional (2D) layered structure. Complex 4 exhibits weak emission due to the quenching effect of Cu(II) ions. Complexes 3 and 5 exhibit rare green emission and blue photoluminesence, respectively. Atomically detailed simulations were used to assess the potential of complexes in gas storage and gas separation applications. The antimicrobial properties of the complexes were also investigated by the broth dilution method (MIC). Complexes 4 and 5 are determined to be highly effective for antimicrobial activity.

Diaqua-bis[4-(dimethyl-amino)benzoato-κO](isonicotinamide-κN)manganese(II).

The title MnII complex, [Mn(C9H10NO2)2(C6H6N2O)(H2O)2], contains two 4-(dimethylamino)benzoate (DMAB) anions, one isonicotinamide (INA) ligand and two coordinated water molecules. One of the DMAB anions acts as a bidentate ligand, while the other is monodentate. The four O atoms in the equatorial plane around the Mn atom form a highly distorted square-planar arrangement, while the distorted octahedral coordination geometry is completed by the N atom of the INA ligand and the O atom of the second water molecule in the axial positions. In the crystal structure, strong intermolecular O—H⋯O, O—H⋯N and N—H⋯O hydrogen bonds link the molecules into a two-dimensional network parallel to (010). Two weak C—H⋯π interactions are also found.