Filiz Yılmaz

Diaqua­bis(2-bromo­benzoato-κO)bis­(nicotinamide-κN1)nickel(II)

The title ZnII complex, [Zn(C7H4BrO2)2(C6H6N2O)2(H2O)2], is centrosymmetric with the Zn atom on an inversion center. The molecule contains two 2-bromobenzoate (BB) and two nicotinamide (NA) ligands and two coordinated water molecules, all ligands being monodentate. The four O atoms in the equatorial plane around the Zn atom form a slightly distorted square-planar arrangement, while the slightly distorted octahedral coordination is completed by the two N atoms of the NA ligands in the axial positions. The dihedral angle between the carboxyl group and the adjacent benzene ring is 31.14 (12)°, while the pyridine and benzene rings are oriented at a dihedral angle of 83.54 (5)°. In the crystal structure, O—H⋯O and N—H⋯O hydrogen bonds link the molecules into infinite chains. A weak C—H⋯π interaction is also present.

Investigation of photosensitively bioconjugated targeted quantum dots for the labeling of Cu/Zn superoxide dismutase in fixed cells and tissue sections

This study presents the development of targeted and antibody cross-linked QDs and explores whether these bioconjugates could specifically and effectively label Cu/Zn superoxide dismutase (SOD1) on fixed cells and tissues. QD-antibody conjugation was achieved by using our previously invented AmiNoacid (monomer) Decorated and Light Underpining Conjugation Approach (ANADOLUCA) method. In this method, we have used a photosensitive aminoacid monomer having ruthenium complex which is a synthetic and inexpensive material for the preparation of bioconjugates. Its specificity was demonstrated by extracting the active enzyme from rat liver lysate by using the bioconjugate. It provided accurate antibody orientation, high specificity and mechanic stability. The protocol steps for QD-antibody conjugation and specimen preparation were described in detail. The nanobioconjugates were prepared under mild conditions (for example in day light), independent of pH and temperature, without affecting conformation and function of protein. This protocol is simple, inexpensive and can be successfully adapted to detect other targets on different cell types and tissues.

Polymeric amylase nanoparticles as a new semi-synthetic enzyme system for hydrolysis of starch

α-Amylase (EC 3.2.1.1; α-D-1,4,glucan glucanohydrolase) catalyzes the hydrolysis of α-D-(1,4)-glucosidic linkages in starch, glycogen, and various malto-oligosaccharides, by releasing α-anomeric products. In this study, a novel method has been developed to prepare nanoprotein particles that carry α-amylase as a monomer by using a photosensitive microemulsion polymerization process. The nanostructured α-amylase with photosensitive features have been characterized by fluorescence spectroscopy, transmission electron microscopy (TEM) and Zeta Sizer. The fluorescence intensity of amylase nanoparticles was determined to be 658 a.u. at 610 nm and the average particle size of nanoamylase was found to be about 71.8 nm. Both free α-amylase and nanoparticles were used in the hydrolysis of starch under varying reaction conditions such as pH and temperature that affect enzyme activity and the results were compared to each other. Km values were 0.26 and 0.87 mM and Vmax values were 0.36 IU mg(-1) and 22.32 IU mg(-1) for nanoenzyme and free enzyme, respectively. Then, thermal stability, storage stability and reusability were investigated and according to the results, activity was preserved 60% at 60 °C; 20% at 70-80 °C temperature values and 80% after 105 days storage. Finally after 10 cycles, the activity was preserved 90% and this novel enzymatic polymeric amylase nanoparticle has showed considerable potential as reusable catalyst.

Mutual recognition of TNT using antibodies polymeric shell having CdS

Click chemistry is the latest strategy called upon in the development of state of the art exponents of bioconjugation. In this study, we have proposed a covalent and photosensitive crosslinking conjugation of the antibody on nano-structures. For this purpose, quantum dots (QDs) without affecting conformation and function of proteins through the ruthenium-chelate based aminoacid monomer linkages have been applied. The aminoacid-monomer linkages called ANADOLUCA (AmiNoAcid Decorated and Light Underpining Conjugation Approach) give reusable oriented and cross-linked anti 2,4,6-trinitrotoluene (TNT) conjugated QD for TNT detection. In this work, a new and simple method has improved to design and prepare high sensitive nanoconjugates for TNT determination. We have demonstrated the use of luminescent QDs conjugated to antibody for the specific detection of the explosive TNT in aqueous environments. The binding affinity of each nanoconjugates for TNT detection by using Langmuir adsorption methods has also been investigated.

Aqua­bis(4-formyl­benzoato-κ2 O 1,O 1′)bis­(isonicotinamide-κN 1)cadmium(II) monohydrate

The asymmetric unit of the title Cd(II) complex, [Cd(C(8)H(5)O(3))(2)(C(6)H(6)N(2)O)(2)(H(2)O)]·H(2)O, contains two 4-formyl-benzoate (FB), two isonicotinamide (INA) ligands, one coordinated and one uncoordinated water mol-ecule; the FB ions act as bidentate ligands. The coordination number of the Cd(II) atom is seven within a CdO(5)N(2) donor set. Intra-molecular O-H⋯O hydrogen bonds link the uncoordinated water mol-ecules to the carboxyl groups. The dihedral angle between the carboxyl-ate groups and the adjacent benzene rings are 17.53 (13) and 16.55 (14)°. In the crystal structure, inter-molecular O-H⋯O, N-H⋯O, N-H⋯N and C-H⋯O hydrogen bonds link the mol-ecules into a supra-molecular structure. The amide group of one of the INA ligands is disordered over two orientations, with an occupancy ratio of 0.759 (3):0.241 (3).

Tetra-aqua-bis(isonicotinamide-κN)cobalt(II) bis-(4-formyl-benzoate) dihydrate.

The asymmetric unit of the crystal structure of the title complex, [Co(C6H6N2O)2(H2O)4](C8H5O3)2·2H2O, contains one-half of the complex cation with the CoII ion located on an inversion center, a 4-formylbenzoate (FB) counter-anion and an uncoordinated water molecule. The four O atoms in the equatorial plane around the CoII ion form a slightly distorted square-planar arrangement with an average Co—O bond length of 2.086 Å; the slightly distorted octahedral coordination is completed by the two N atoms of the isonicotinamide (INA) ligands at a slightly longer distance [2.1603 (14) Å] in the axial positions. The dihedral angle between the carboxylate group and the attached benzene ring is 5.93 (13)°, while the pyridine and benzene rings are oriented at a dihedral angle of 3.09 (6)°. In the crystal structure, O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds link the molecules into a three-dimensional network. π–π Contacts between the benzene and pyridine rings [centroid–centroid distance = 3.758 (1) Å] may further stabilize the crystal structure.

catena-Poly[[(4-formyl-benzoato-κO)(isonicotinamide-κN)zinc(II)]-μ-4-formyl-benzoato-κO:O].

In the title compound, [Zn(C8H5O3)2(C6H6N2O)]n, the ZnII ion is tetrahedrally coordinated by two formylbenzoate (FB) and one isonicotinamide (INA) ligands while symmetry-related FB ligands bridge adjacent ZnII ions, forming polymeric chains along the b axis. The carboxylate groups in the two FB ions are twisted away from the attached benzene ring by 9.07 (2) and 26.2 (2)°. The two benzene rings of the FB ions are oriented at a dihedral angle of 81.30 (5)°. In the crystal, adjacent polymeric chains interact via N—H⋯O and C—H⋯O hydrogen bonds, π–π contacts between the formylbenzoate rings [centroid–centroid distance = 3.7736 (8) Å] and weak C—H⋯π interactions, forming a three-dimensional network.

Tetra­kis[μ-4-(methyl­amino)­benzoato-κ2O:O′]bis­[(N,N-diethyl­nicotinamide-N1)zinc(II)] dihydrate

The title molecule, [Zn2(C8H8NO2)4(C10H14N2O)2]·2H2O, is a centrosymmetric binuclear complex, with two ZnII ions [Zn⋯Zn’ = 2.9301 (4) Å] bridged by four methylaminobenzoate (MAB) ligands. The four nearest O atoms around each ZnII ion form a distorted square-planar arrangement with the distorted square-pyramidal coordination completed by the pyridine N atom of the N,N-diethylnicotinamide (DENA) ligand. Each ZnII ion is displaced by 0.3519 (2) Å from the plane of the four O atoms, with an average Zn—O distance of 2.030 Å. The dihedral angles between carboxylate groups and adjacent benzene rings are 10.57 (10) and 16.63 (12)°, while the benzene rings are oriented at a dihedral angle of 81.84 (5)°. The pyridine ring is oriented at dihedral angles of 40.49 (6) and 51.25 (6)° with respect to the benzene rings. In the crystal structure, intermolecular O—H⋯O and N—H⋯O hydrogen bonds link the molecules into a three-dimensional network. The π–π contact between the inversion-related pyridine rings [centroid–centroid distance = 3.633 (1) Å] may further stabilize the crystal structure.

Tetraaquabis(isonicotinamide-κN1)cobalt(II) bis(4-formylbenzoate) dihydrate

The asymmetric unit of the title complex, [Ni(C6H6N2O)2(H2O)4](C8H5O3)2·2H2O, contains one-half of the complex cation with the NiII atom located on an inversion center, a 4-formylbenzoate (FB) counter-anion and an uncoordinated water molecule. The four O atoms in the equatorial plane around the Ni atom form a slightly distorted square-planar arrangement and the slightly distorted octahedral coordination is completed by the two N atoms of the isonicotinamide (INA) ligands at a sligthly longer distance in the axial positions. The dihedral angle between the carboxylate group and the attached benzene ring is 8.14 (11)°, while the pyridine and benzene rings are oriented at a dihedral angle of 3.46 (6)°. In the crystal structure, O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds link the molecules into a three-dimensional network. π–π Contacts between the benzene and pyridine rings [centroid–centroid distance = 3.751 (1) Å] may further stabilize the crystal structure.

Bis(μ-2-fluoro­benzoato-1:2κ2O:O′)(2-fluoro­benzoato-1κ2O,O′)(2-fluoro­benzoato-2κO)dinicotinamide-1κN1,2κN1-dizinc(II)–2-fluoro­benzoic acid (1/1)

The asymmetric unit of the title compound, [Zn2(C7H4FO2)4(C6H6N2O)2]·C7H5FO2, consists of a binuclear ZnII complex bridged by two carboxyl groups of 2-fluorobenzoate (FB) anions and a 2-fluorobenzoic acid molecule. The two bridging FB anions, one chelating FB anion and one nicotinamide (NA) ligand coordinate to one Zn cation with a distorted square-pyramidal geometry, while the two bridging FB anions, one monodentate FB anion and one NA ligand coordinate to the other Zn cation with a distorted tetrahedral geometry. Within the binuclear molecule, the pyridine rings are oriented at a dihedral angle of 19.41 (14)°. In the crystal structure, the uncoordinated 2-fluorobenzoic acid molecules are linked by O—H⋯O hydrogen bonding, forming centrosymmetric supramolecular dimers. Intermolecular N—H⋯O hydrogen bonds link the complex molecules into a three-dimensional network. The π–π contacts between nearly parallel pyridine and benzene rings [dihedral angles of 19.41 (14) and 12.72 (16)°, respectively, centroid–centroid distances = 3.701 (2) and 3.857 (3) Å] may further stabilize the crystal structure. The fluorine atoms in two FB ligands are disordered over two positions, with occupancy ratios of 0.70:0.30.