Mustafa Serkan Soylu

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.

Synthesis and characterization of new heterometallic cyanido complexes based on [Co(CN)6]3− building blocks: crystal structure of [Cu2(N-bishydeten)2Co(CN)6]·3H2O having a strong antiferromagnetic exchange

A tetradentate N- and O- donor, N,N-bis(2-hydroxyethyl)-ethylenediamine, (N-bishydeten), has been employed to synthesize four new heterometallic cyanido complexes, [Ni2(N-bishydeten)2Co(CN)6]·3H2O (C1), [Cu2(N-bishydeten)2Co(CN)6]·3H2O (C2), [Zn2(N-bishydeten)2Co(CN)6]·5H2O (C3) and K[Cd(N-bishydeten)Co(CN)6]·1.5H2O (C4). Characterization of the complexes was performed using IR and EPR spectroscopy (for C2), thermal analysis and elemental analysis techniques. The crystal structure of C2 was determined by the X-ray single crystal diffraction technique. The asymmetric unit of C2 consists of cyanido-bridged trinuclear Cu1Cu2Co3 units {-CN-Cu1(N-bishydeten)-μ-O-Cu2(N-bishydeten)-NC-Co3(CN)4-CN-} and three water molecules. The water molecules are situated in the inter-fragment spaces. The [Cu2(N-bishydeten)2]2+ cations are linked to the [Co(CN)6]3− anions via two cyanido bridges to give a 1D neutral zigzag chain. One of two N-bishydeten cations bridges five coordinated Cu1 and six coordinated Cu2 through deprotonated η1-O2 and the charge of C2 is counterbalanced by this η1-O2. The IR spectrum of C2 is quite different from other complexes, three ν(CN) absorption bands were observed due to different cyanido groups in its structure. The thermal decomposition of C1–C4 is processed in multistages. Variable temperature magnetic susceptibility measurement recorded in the 10–300 K range showed the presence of a strong antiferromagnetic exchange interaction in C2 between Cu1 and Cu2 by η1-O2.

Crystal structure, DFT and HF calculations and radical scavenging activities of (E)-4,6-dibromo-3-methoxy- 2-((3-methoxyphenylimino)methyl)phenol

In this study, (E)-4,6-dibromo-3-methoxy-2-[(3-methoxyphenylimino)methyl]phenol has been synthesized and characterized by using X-ray technique and FT-IR experimentally and using B3LYP/6-31G(d,p) and HF/6-31G(d,p) methods theoretically. The intermolecular and intramolecular interactions of the title compound have been determined according to X-ray results. The molecular geometry, vibrational frequencies of the title compound in the ground state have been calculated using the density functional B3LYP and HF method with the 6-31G(d,p) basis set and calculated bond parameters and vibrational frequencies values show good agreement with experimental values. Theoretical and experimental results show that tautomeric form of the structure is phenol-imine form. Besides HOMO-LUMO energy gap, molecular electrostatic potential map were performed at B3LYP/6-31G(d,p) level. It is worthy note of that, the free radical scavenging activities of the title compound were assessed using DPPH˙, DMPD˙(+), and ABTS˙(+) assays. The obtained results show that the title compound has effective DPPH˙ (SC50 2.61±0.09 μg/mL), DMPD˙(+) (SC50 2.82±0.14 μg/mL), and ABTS˙(+) (SC50 4.91±0.18 μg/mL) radical scavenging activities when compared with standard antioxidants (BHA, rutin, and trolox).

Molecular structure, quantum mechanical calculation and radical scavenging activities of (E)-4,6-dibromo-2-((3,5-dimethylphenylimino) methyl)-3-methoxyphenol and (E)-4,6-dibromo-2- ((2,6-dimethylphenylimino)methyl)-3-methoxyphenol compounds

In this study, (E)-4,6-dibromo-2-[(3,5-dimethylphenylimino)methyl]-3-methoxyphenol and (E)-4,6-dibromo-2-[(2,6-dimethylphenylimino)methyl]-3-methoxyphenol compounds have been synthesized and characterized by using X-ray crystallographic method, FT-IR and Density functional method. The molecular geometry, vibrational frequencies of the title compounds in the ground state have been calculated by using B3LYP with the 6-31G(d,p) basis set. The tautomeric form of the compounds has been demonstrated by using single crystal X-ray method, FT-IR spectrometer and DFT method. In addition, HOMO-LUMO energy gap, molecular electrostatic potential map and NBO analysis of the compounds are performed at B3LYP/6-31G(d,p) level. It may be remarked that the free radical scavenging activities of the title compounds were assessed using DPPH, DMPD+, and ABTS+ assays. The obtained results show that especially compound 2 has effective DPPH (SC50 1.52±0.14 μg/mL), DMPD+ (SC50 1.22±0.21 μg/mL), and ABTS+ (SC50 3.32±0.17 μg/mL) scavenging activities compared with standards (BHA, rutin, and trolox).

Synthesis, spectral, thermal, and structural studies of copper(II)-squarate coordination polymer with 2-hydroxyethylpyridine, {[Cu(μ-sq)(etpy)2] · H2O} n

Polynuclear Cu(II)-squarate complex with 2-hydroxyethylpyridine, {[Cu(μ-sq)(etpy)2] · H2O} n has been prepared and characterized by elemental analysis, magnetic susceptibility, thermal analysis, IR, and UV-Vis spectroscopic studies (H2sq = squaric acid and etpy = 2-hydroxyethylpyridine). The structure of the complex was determined by single crystal X-ray diffraction. Density functional theory (DFT) and Hartree–Fock (HF) calculations were performed using the GAUSSIAN 03 program. The complex crystallizes in the monoclinic system, space group P21/c. The structure contains chains of squarato-O 1,O 3-bridged polynuclear copper(II) units held together by intermolecular hydrogen bonds, weak π–π and van der Waals interactions. The distorted octahedral geometry of Cu(II) is completed by two neutral bidentate etpy ligands through the nitrogen of pyridine and hydroxyl O atom. Thermal decomposition of the complex is studied from 30 to 500°C in a static air atmosphere.

Structural and spectroscopic characterization of a thiosemicarbazidatodioxouranium(VI) complex: A combined experimental and DFT study

The title thiosemicarbazidatodioxouranium(VI) compound was synthesized and characterized by FT-IR, NMR and UV-vis spectroscopies. Solid-state structure of the compound was confirmed by X-ray crystallography. Besides, the molecular geometry, vibrational frequencies and gauge-independent atomic orbital (GIAO) (1)H and (13)C NMR chemical shift values of the compound in the ground state have been calculated using the density functional theory (DFT/B3LYP) method with the 6-311++G(d,p) basis set for the C, H, Cl, N, O, S atoms and SDD pseudo-potential for the U atom, and compared with the experimental data. Using the TD-DFT method, electronic absorption spectra of the compound have been predicted at same level. As a result, a good agreement is obtained between the experimental and theoretical ones.

Five novel dicyanidoaurate(I)-based complexes exhibiting significant biological activities: synthesis, characterization and three crystal structures

Five new cyanido-bridged coordination polymers having closed formulae [Ni(hydeten)Au2(CN)4] (C1), [Ni(hydeten)2Au2(CN)4]·H2O (C2), [Cu(hydeten)2Au2(CN)4]·CH3OH (C3), [Zn(hydeten)2 Au2(CN)4]·H2O (C4), and [Cd(hydeten)2Au2(CN)4]·H2O (C5) (hydeten: N-(2-hydroxyethyl)-ethylenediamine) have been prepared and characterized by elemental, thermal, FT-IR and XRD (C3, C4 and C5) measurement techniques. The anticancer, antibacterial and antifungal activities of the complexes are also investigated. The C3, C4 and C5 units according to XRD analyses are linked to each other via –CN–M(hydeten)–NC–Au(1)–CN–M(hydeten)–CN– chains (MII = Cu, Zn and Cd) and aurophilic interacted –Au(1)(CN)2–Au(2)(CN)2–Au(1)(CN)2–Au(2)(CN)2– zig-zag shaped chains along the a axis. C1, C2 and C4 show significant antifungal effects against several plant pathogenic fungi, while surprisingly C3 exhibits a considerable antibacterial effect against Gram negative E. coli. The studies of the antiproliferative activity on Hela, HT29 and C6 tumor cell lines indicated the anticancer potential of these complexes even at low doses.

5-Diethyl-amino-2-[(E)-(2,4-dimeth-oxy-phen-yl)imino-meth-yl]phenol.

The title Schiff base, C19H24N2O3, exists in the crystal structure in the phenol–imine tautomeric form with an intramolecular O—H⋯N hydrogen bond. The planes of the aromatic rings form a dihedral angle of 36.8 (8)°. The crystal packing is characterized by C—H⋯O hydrogen bonds and π–π stacking interactions [centroid–centroid distance = 3.478 (4)Å].

8-{(E)-[(4-Chloro-phen-yl)imino]-meth-yl}-1,1,7,7-tetra-methyl-1,2,3,5,6,7-hexa-hydro-pyrido[3,2,1-ij]quinolin-9-ol.

The title Schiff base, C23H27ClN2O adopts the phenol–imine tautomeric form, with an intramolecular O—H⋯N hydrogen bond, which generates an S(6) ring motif. Three C atoms of the heterocyclic moiety of the hexahydropyridoquinoline unit, as well as the two methyl groups bonded to one of these C atoms, are disordered over two set of sites, with anoccupancy ratio of 0.740 (4):0.260 (4).

(E)-3-Chloro-N-[(2-eth-oxy-naphthalen-1-yl)methyl-idene]aniline.

In the title compound, C19H16ClNO, the dihedral angle between the naphthalene ring system and the chlorobenzene ring is 61.90 (10)° and the C—N—C—C torsion angle is 174.6 (2)°. The molecular structure is stabilized by an intramolecular C—H⋯N hydrogen bond. The crystal structure features π–π stacking interactions [centroid–centroid distances = 3.7325 (17) and 3.8150 (17) Å].