Search

A versatile approach to the preparation of [Ir(LL)(2)Cl-2](PF6) type complexes is reported, in which LL is an (NN)-N- bound polypyridyl ligand [X(2)bpy, X(2)phen, where X = H-, CH3-, (CH3)(3)C-, or phenyl-, and bpy = 2,2-bipyridyl, phen = 1,10-phenanthroline] as well as their deuterated analogues. In the synthesis of [Ir(bpy)(2)Cl-2]PF6 (I) and its deuterated analogue (III), the cyclometallated complexes [Ir(bpy)(2)(bpy-C-N)](PF6)(2) (II) and [Ir([D-8]-bpy)(2)([D-8]-bpy-C-N)](PF6)(2) (IV) were also obtained. The complexes are characterised by H-1 NMR, UV/Vis absorption and emission spectroscopy. The effect of deuteration on emission quantum yields and emission lifetimes is discussed. The ready availability of these complexes through efficient scaleable synthetics routes opens new opportunities for their use, especially in energy related applications.

A versatile approach to the preparation of [Ir(LL)(2)Cl-2](PF6) type complexes is reported, in which LL is an (NN)-N- bound polypyridyl ligand [X(2)bpy, X(2)phen, where X = H-, CH3-, (CH3)(3)C-, or phenyl-, and bpy = 2,2-bipyridyl, phen = 1,10-phenanthroline] as well as their deuterated analogues. In the synthesis of [Ir(bpy)(2)Cl-2]PF6 (I) and its deuterated analogue (III), the cyclometallated complexes [Ir(bpy)(2)(bpy-C-N)](PF6)(2) (II) and [Ir([D-8]-bpy)(2)([D-8]-bpy-C-N)](PF6)(2) (IV) were also obtained. The complexes are characterised by H-1 NMR, UV/Vis absorption and emission spectroscopy. The effect of deuteration on emission quantum yields and emission lifetimes is discussed. The ready availability of these complexes through efficient scaleable synthetics routes opens new opportunities for their use, especially in energy related applications.

Two nickel(II) complexes with substituted bipyridine ligand of the type [Ni(NN)3](ClO4)2, where NN is 4,4′-dimethyl-2,2′-bipyridine (dimethylbpy) (1) and 4,4′-dimethoxy-2,2′-bipyridine (dimethoxybpy) (2), have been synthesized, characterized, and their interaction with DNA and bovine serum albumin (BSA) studied by different physical methods. X-ray crystal structure of 1 shows a six-coordinate complex in a distorted octahedral geometry. DNA-binding studies of 1 and 2 reveal that both complexes sit in DNA groove and then interact with neighboring nucleotides differently; 2 undergoes a partial intercalation. This is supported by molecular-docking studies, where hydrophobic interactions are apparent between 1 and DNA as compared to hydrogen bonding, hydrophobic, and π–π interactions between 2 and DNA minor groove. Moreover, the two complexes exhibit oxidative cleavage of supercoiled plasmid DNA in the presence of hydrogen peroxide as an activator in the order of 1 > 2. In terms of interaction with BSA, the results of spectroscopic methods and molecular docking show that 1 binds with BSA only via hydrophobic contacts while 2 interacts through hydrophobic and hydrogen bonding. It has been extensively demonstrated that the nature of the methyl- and methoxy-groups in ligands is a strong determinant of the bioactivity of nickel(II) complexes. This may justify the above differences in biomolecular interactions. In addition, the in vitro cytotoxicity of the complexes on human carcinoma cells lines (MCF-7, HT-29, and U-87) has been examined by MTT assay. According to our observations, 1 and 2 display cytotoxicity activity against selected cell lines. Communicated by Ramaswamy H. Sarma

A versatile approach to the preparation of [Ir(LL)(2)Cl-2](PF6) type complexes is reported, in which LL is an (NN)-N- bound polypyridyl ligand [X(2)bpy, X(2)phen, where X = H-, CH3-, (CH3)(3)C-, or phenyl-, and bpy = 2,2-bipyridyl, phen = 1,10-phenanthroline] as well as their deuterated analogues. In the synthesis of [Ir(bpy)(2)Cl-2]PF6 (I) and its deuterated analogue (III), the cyclometallated complexes [Ir(bpy)(2)(bpy-C-N)](PF6)(2) (II) and [Ir([D-8]-bpy)(2)([D-8]-bpy-C-N)](PF6)(2) (IV) were also obtained. The complexes are characterised by H-1 NMR, UV/Vis absorption and emission spectroscopy. The effect of deuteration on emission quantum yields and emission lifetimes is discussed. The ready availability of these complexes through efficient scaleable synthetics routes opens new opportunities for their use, especially in energy related applications.

This thesis focuses on the design, synthesis and development of dynamic multivalent nanostructures such as supramolecular dendrimers, liposomes and gold-functionalized nanostructures. These structures can be used for drug delivery and molecular sensing applications. This thesis is divided into three parts: In part one, a general introduction to self-assembly, dynamic systems, metalligand exchange, nanostructured dendritic scaffolds, liposomes and gold nanostructures is given. In part two, a microwave approach is presented as an efficient method for the regioselective deuteration of bipyridine scaffolds. Dynamic systems based on transition metal-bipyridine coordination complexes were investigated. The compositional self-adaptation and kinetics of these dynamic systems were successfully assessed by ESI-MS. Based on this amphiphilic dendrimers/metallodendrimers were also designed and synthesized via a convergent strategy. Their ability to self-assemble into supramolecular assemblies and their controlled disassembly was effectively demonstrated. In part three, two types of drug delivery systems based on dynamic multivalent nanostructures of glycodendrimers/metalloglycodendrimers and drugpresenting liposomes were developed. The dynamic self-assembly of these architectures into supramolecular nanostructures with site-specific functionality through interacting carbohydrate or cholesterol moieties was assessed. The host-guest interaction/encapsulation and controlled release with external stimuli were studied using a fluorescent probe, as well as selected drug molecules. The antibacterial property of the drug delivery systems was also evaluated, demonstrating an enhanced bactericidal activity. A new, rapid and simple approach for the functionalization of plasmonic gold nanostructured surfaces was also developed. The optical performance and light-specific sensitivity of the fluorescent probe on the resulting nanostructures were also presented. QC 20151119

The single crystal X-ray structure of the novel multimodal ligand 6,6'-bis(2-(di(pyridin-2-yl)methylene)-1-methylhydrazinyl)-2,2'-bipyridine, C34H28N10 (L), was determined at 120 (2) K. The ligand possesses a centre of symmetry that generates a planar bipyridyl core with the hydrazone substituents in a trans-geometry. The di-2-pyridyl moieties at either terminus of the molecule twist out of the plane (52.90 and 56.32 Å). The crystal structure comprises 2-dimensional ribbons that stack about each other so as to optimise van der Waals interactions and packing efficiency. Studies of the coordination properties of the novel multimodal ligand with copper(I) show that 2 ligand strands wrapped around the copper(I) having a preference for tetrahedral geometry to furnish a supramolecular self-assembled of a double-stranded tri-nuclear helical complex, {[Cu3L2](PF6)3\cdot 3H2O} (1), as revealed by the ESI-MS, and further characterised by 1H-NMR, UV-Vis, and FT-IR spectra.

WOS: 000282762200009, The single crystal X-ray structure of the novel multimodal ligand 6,6'-bis(2-(di(pyridin-2-yl) methylene)-1- methylhydrazinyl)-2,2'-bipyridine, C34H28N10 (L), was determined at 120 (2) K. The ligand possesses a centre of symmetry that generates a planar bipyridyl core with the hydrazone substituents in a transgeometry. The di-2-pyridyl moieties at either terminus of the molecule twist out of the plane (52.90 and 56.32 angstrom). The crystal structure comprises 2-dimensional ribbons that stack about each other so as to optimise van der Waals interactions and packing efficiency. Studies of the coordination properties of the novel multimodal ligand with copper(I) show that 2 ligand strands wrapped around the copper(I) having a preference for tetrahedral geometry to furnish a supramolecular self-assembled of a double-stranded tri-nuclear helical complex, {[Cu3L2](PF6)3 center dot 3H(2)O} (1), as revealed by the ESI-MS, and further characterised by (1) H-NMR, UV-Vis, and FT-IR spectra., Zonguldak Karaelmas UniversityBulent Ecevit University [2008-1302-08]; UK Engineering and Physical Sciences Research CouncilEngineering & Physical Sciences Research Council (EPSRC), This work was supported by the research project fund of Zonguldak Karaelmas University (grant No. 2008-1302-08) and the UK Engineering and Physical Sciences Research Council.

The synthesis of a series of N,N'-disubstituted acyclic (AL) and cyclic (CL) aza-bridged ligands incorporating 2,2-pipryidine subunits is described. 1H-NMR and IR spectral data support the proposed ligand structures. Dynamic 1H-NMR studies on diurea and diamide derivatives point to the presence of slowly interconverting conformers on the 1H-NMR time-scale, owing to N−H···N hydrogen bonding and/or a restricted rotation around the amide bonds. The ligands synthesized form 1:1 complexes with divalent transition metal ions. Upon complexation, bis-ester derivatives AL5 and CL5 undergo a metal-induced hydrolysis of the ester groups to carboxyl functions, which act as additional binding sites for the metal ion, as well as hydrogen-bonding donor-acceptor binding site to produce dimeric complexes.