Swapan Kumar Jana

Synthesis and X-ray structure of a new zinc(II) coordination polymer: interaction with DNA and double stranded RNA and elucidation of the molecular aspects of the binding to bovine serum albumin

A novel ligand bridged zinc(II) coordination polymer, [Zn(4-Me-5-CHOIm)2(HCOO)](ClO4) has been synthesized and characterized by single crystal X-ray diffraction studies. The structural analysis revealed that the complex exhibits two types of 2D network by weak and strong hydrogen bonds. Interestingly, an extended supramolecular layer network has been observed in the solid state structure through weak face-to-face π-stacking interactions. The interaction of the complex with calf thymus DNA (CT-DNA) and double stranded ribonucleic acid, polyinosinic·polycytidylic acid (poly(I)·poly(C)) has been explored by UV-Vis absorption, fluorescence displacement, circular dichroism (CD) spectral and isothermal titration calorimetric (ITC) methods. The spectral titration method revealed that the compound could interact with CT-DNA and RNA through partial intercalation with a binding affinity of an order of 105. ITC experiments indicate an exothermic reaction in both cases but RNA interaction is favored by positive entropy. On the other hand, the complex could quench the intrinsic fluorescence of BSA in a static quenching process with a quenching constant of the order of 104. A specific binding distance of 2.75 nm between Trp 212 (donor) and the complex (acceptor) was obtained from Forster resonance energy transfer studies (FRET). Competitive binding using site markers, warfarin and ibuprofen, having definite binding sites demonstrated that the complex binds to site I (subdomain IIA) on BSA. Circular dichroism (CD), synchronous fluorescence, and three-dimensional fluorescence spectroscopy experiments reveal that binding with the complex alters the BSA secondary structure by a reduction of the α-helical organization and increases the coiled structure and the ITC experiment indicates that the binding was enthalpy driven with a slight negative entropy effect.

Three-Dimensional Silver(I)-Thiodiglycolate Coordination Polymer with Weak Ag–Ag Bond

Reaction of thiodiglycolic acid and silver nitrate under ultrasonic condition forms a 3D supramolecular framework of silver with composition [Ag2(tdga)]n (1). X-ray single crystal structure analysis reveals repetition of paddle wheel units in the network. A weak Ag–Ag bond is present in the complex. A new μ8-coordination mode of the thiodiglycolate ligand is identified. Photoluminescence and thermal characterization of the complex was examined.Graphical AbstractNovel 3D silver coordination polymer with Ag–Ag bond is synthesized using thiodiglycolic acid ligand and characterized by X-ray diffraction, IR, photoluminescence and TG analysis. The ligand displays a unique type of coordination.

Synthesis, Characterization and Crystal Structure of a New 3D Cadmium(II) Coordination Polymer: Binding Interaction with DNA and Double Stranded RNA

A new cadmium (II) complex, [Cd(4-Me-5-CHOIm)2Cl2] has been synthesized and characterized using single crystal X-ray diffraction study. The interaction of the complex with calf thymus DNA (CT-DNA) and double stranded RNA [polyinosinic·polycytidylic acid (poly(I)·poly(C)] has been investigated by various biophysical techniques. The interaction of the complex with CT-DNA and RNA displays a binding order of 105.Graphical AbstractA new cadmium (II) coordination polymer, [Cd(4-Me-5-CHOIm)2Cl2] has been synthesized. The binding of the complex with double stranded DNA, RNA has been carried out by different spectroscopic techniques and energetic of the interaction was derived from isothermal titration calorimetry (ITC).

Two New Coordination Polymers of Manganese(II) with O/O- and N/O-Donor Ligands: Synthesis, Structure, Luminescence Study and Thermal Behavior

Two new coordination polymers of Mn(II), of formula C12H18MnN8O6 (1) and C21H16MnO9 (2), have been synthesized by using two different kind of ligands, namely 5-methyl-7-oxo-(1,2,4)triazolo(1,5-a)pyrimidine (HmtpO) and 3-(2-furyl)prop-2-enoic acid (fproH). The X-ray single crystal structure analysis shows that complex 1 is a discrete molecular complex that turns into a 3D network through hydrogen bonding and π–π stacking interactions. Complex 2 is 1D polymeric chain comprising hexacoordinated Mn(II) centers. Luminescence study revealed the presence of intraligand π*–π transitions. The thermal stability of the complexes has been also investigated by thermogravimetric analysis.Graphical AbstractTwo new coordination polymer of Mn(II) have been synthesized. X-ray single crystal structure analysis revealed that complex 1 is 3D via supramolecular interactions and complex 2 is a 1D chain. Luminescence and thermal characterization has been done for the complexes.

Sensing of tryptophan by a non-toxic cobalt(II) complex

A non-toxic, hemocompatible, fluorescent probe as cobalt(II) based complex [Co(PS)4](ClO4)2 (1) (PS: N-pyridylsalicylaldimine) was successfully synthesized and characterised by single crystal X-ray diffraction studies. The structural analysis revealed that 1 exhibits intramolecular π–π interaction. The recognition ability of 1 towards various amino acids and proteins were studied by UV-vis and fluorescence spectroscopy. The titled complex selectively sense the Trp by reducing its internal fluorescence quenching. It also sense BSA with a detection limit of 56 nM. The binding constant of 1 was analysed by Hills equation and it was found that it binds to Trp and BSA in the order of 103 and 104 respectively.

Synthesis, crystal structure, thermal, and photoluminescence properties of Cd carboxylate coordination polymers: a new 2-D structure and reinvestigation of Cd tartrate

A new 2-D coordination polymer, [Cd(HnicO)(pyc)(H2O)] n (1) (H2nicO = 2-oxynicotinic acid, pycH = pyridine-4-carboxylic acid), and the [Cd3(tartr)3] n salt (2) (tartrH2 = tartaric acid) have been synthesized and structurally characterized. The former is stabilized by H-bonds to give a 3-D architecture. Complex 2, that represents a reinvestigation of Cd tartrate, has been compared with isomorphous [Cd3(tartr)3] structures in terms of the unit cell void and the respective water content, indicating for these compounds the aptitude to crystallize with a small, but different, amount of lattice water. Thermogravimetric and luminescent characterization of 1 were performed.

Structural variability of Ag(I) metal–organic networks: C–H⋯π and metal⋯π interactions

Abstract The synthesis and X-ray structural characterization of two silver(I) coordination polymers, [Ag2(bpp)2(Phdac)]·5H2O (1) and [Ag2(bpp)(HSSal)] (2), are reported, where bpp = 4,4′-trimethylene dipyridine, H2Phdac = 1,4-phenylenediacetic acid, and H3SSal = 5-sulfosalicylic acid. X-ray crystallography reveals that the structures are stabilized through hydrogen bonding interactions. The C–H⋯π and metal⋯π interactions of aromatic molecules play a crucial role in building a layered framework. Intricate combinations of the weak non-covalent interactions have been analyzed to explore cooperativity and competitiveness in the solid-state structures.

Sensing of Zn2+ion by N-Furfurylsalicylaldimine Based on CHEF Process†

AbstractThe recognition ability of N-Furfurylsalicylaldimine (HL) toward various cations (Pb2+, Hg2+, Ba2+, Cd2+, Ag+, Zn2+, Cu2+, Ni2+, Co2+, K+, Sr2+, and Na+) has been studied by UV–Vis and fluorescence spectroscopy. The compound showed highly selective fluorescence signaling behaviour for Zn2+ ions in methanol-water medium based on CHEF process and is capable of distinguishing Zn2+ from Cd2+ ion. From single crystal X-ray analysis it is revealed that a Zn2+ ion binds two ligand molecules through imine nitrogen and phenolate oxygen atom. FigureN-Furfurylsalicylaldimine as a selective sensing of Zn2+ ion through CHEF process. The x-ray structure of the receptor-Zn(II) complex shows 2:1 stochiometry