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Cytotoxicity, cellular uptake of copper(i) complexes containing 1,8-naphthalimide conjugates have been investigated.

Qualitative and quantitative analysis of mercury at concentration levels as low as parts per billion (ppb) is a basic and practical concern. The vast majority of research in this field has centered on the development of potent chemosensor to monitor mercuric (Hg

The synthesized copper complexes have good anticancer activity and induce an apoptotic mode of cell death.

Ordinary least squares estimator (OLS) becomes unstable if there is a linear dependence between any two predictors. When such situation arises ridge estimator will yield more stable estimates to the regression coefficients than OLS estimator. Here we suggest two modified ridge estimators based on weights, where weights being the first two largest eigen values. We compare their MSE with some of the existing ridge estimators which are defined in the literature. Performance of the suggested estimators is evaluated empirically for a wide range of degree of multicollinearity. Simulation study indicates that the performance of the suggested estimators is slightly better and more stable with respect to degree of multicollinearity, sample size, and error variance.

Two cationic iridium(III) complexes, [Ir(ppy)2((tdzp))]+ (1) and [Ir(bhq)2((tdzp))]+ (2) {ppy = 2-phenylpyridine, bhq = benzo[h]quinoline, tdzp = [1,2,5]-thiadiazolo-[3,4-f]-[1,10]-phenanthroline}, have been synthesized and structurally characterized. The molecular structures of the iridium complexes have been confirmed by single-crystal X-ray structure determination. Extensive hydrogen bonding between lattice water molecules, solvated methanol, and chloride anions is observed in the crystal structure of complex 1, which leads to the formation of 1D polymeric cyclic hybrid water–chloride–methanol clusters. The complexes show different photophysical properties in different solvents. The experimental photo-physical properties of the synthesized iridium(III) complexes match well with the theoretically calculated results obtained by density functional theory (DFT) and time-dependent density functional theory (TD-DFT) studies. The HOMO of complexes 1 and 2 is restricted on the iridium and cyclometalated aromatic ligands, while the LUMO, LUMO+1, and LUMO+2 are primarily restricted on the polypyridyl tdzp ligand. The interaction of the complexes with calf thymus DNA (CT-DNA) was investigated by absorption titration and emission titration experiments. Furthermore, the cytotoxicity and cellular localization properties of these complexes towards HeLa cells have been investigated.

Coordination polymer {[Cu(bpy)(bpe)(NO3)2]·(H2O)4}n (CP1) has been synthesized using [Cu(bpy)(NO3)2] (where bpy = 2,2′-bipyridine) and bpe (bpe = 1,2-bis(4-pyridyl)ethane as a spacer in equimolar ratio. CP1 was characterized by using Infrared spectroscopy, elemental analysis, and single crystal X-ray diffraction. The crystal structure confirms that the CP1 is formed with a bridging bpe linker giving rise to helical chain in one-dimensional (1D) structure. Copper ion is connected to two nitrogen atoms from bpy, two oxygen atoms from nitrate anions (major component) and two nitrogen atoms from two bpe ligands. There is an additional minor component which is five coordinate. The hydrogen bonding links the helical chains to generate a three dimensional (3D) network structure. A one-dimensional coordination polymer {[(Cu(bpy)(bpe)(NO3)2]·H2O)4}n (CP1) has been synthesized using [Cu(bpy)(NO3)2] (where bpy = 2,2′-bipyridine) as a building block and bpe (bpe = 1,2-bis(4-pyridyl)ethane) as a spacer in a equimolar ratio.

Two one-dimensional (1D) coordination polymers (CPs), namely catena-poly[[[aqua(2,2′-bipyridine-κ2 N,N′)(nitrato-κO)copper(II)]-μ-1,3-bis(pyridin-4-yl)propane-κ2 N:N′] nitrate], {[Cu(NO3)(C10H8N2)(C13H14N2)(H2O)]·NO3} n (1), and catena-poly[[[aqua(nitrato-κO)(1,10-phenanthroline-κ2 N,N′)copper(II)]-μ-1,3-bis(pyridin-4-yl)propane-κ2 N:N′] nitrate], {[Cu(NO3)(C12H8N2)(C13H14N2)(H2O)]·NO3} n (2), have been synthesized using [Cu(NO3)(NN)(H2O)2]NO3, where NN = 2,2′-bipyridine (bpy) or 1,10-phenanthroline (phen), as a linker in a 1:1 molar ratio. The CPs were characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis and single-crystal X-ray structure determination. The 1,3-bis(pyridin-4-yl)propane (dpp) ligand acts as a bridging ligand, leading to the formation of a 1D polymer. The octahedral coordination sphere around copper consists of two N atoms from bpy for 1 or phen for 2, two N atoms from dpp, one O atom from water and one O atom from a coordinated nitrate anion. Each structure contains two crystallographically independent chains in the asymmetric unit and the chains are linked via hydrogen bonds into a three-dimensional network.

The ligand 4-(naphthalen-1-yl)-1-((quinolin-2-yl)methylene)thiosemicarbazide (HL) and its cobalt(III), nickel(II) and copper(II) complexes of type [CoIIIL2]Cl (1), [NiIIL2] (2), [CuIILCl] (3) were synthesized and structurally characterized by various spectral techniques. The structure of 2 was confirmed through single-crystal X-ray structure determination. Complex 2 crystallized in the triclinic system with the P-1 space group. HL acts as tridentate chelate with N,N,S-donor sites. The spectrochemical analysis of all the complexes showed that, in the case of 1 and 2, the metal-to-L ratio is 1:2, while in the case of 3, the copper-to-ligand ratio is 1:1. The antitubercular studies of the complexes were explored in vitro against the Mycobacterium strain, M. H37Rv. Complex 3 has better activity compared to the standard drug pyrazinamide. Cytotoxicity studies were carried out on human embryonic kidney cell lines (HEK293). Inhibition of tuberculosis bacteria has increased upon complexation compared to the free ligand.

A one-dimensional coordination polymer {[(Co(pic)2(bpe)]·2CH3OH}n(1) has been synthesized using [Co(pic)2(H2O)2]·2H2O where pic = picolinate as a building block and 1,2-bis(4-pyridyl)ethane (bpe) as an linker in a 1:1 M ratio. This compound was characterised by using elemental analysis, IR spectroscopy, thermogravimetric analysis and single crystal X-ray diffraction. Single crystal X-ray structural analysis revealed that the compound 1 formed by bridging bpe ligand which gives rise to the one-dimensional (1D) linear chain. In the crystal structure coordination sphere consists of two oxygen atoms and two nitrogen atoms of the two picolinato and two nitrogen atoms of two bpe ligand. Weak interactions such as hydrogen-bonding, π⋯π stacking interaction join the polymeric chain to generate three dimensional network structures. The framework is stable up to 232 °C and nitrogen adsorption measurement reveals the adsorption of 11.4 cc g−1 at P/P0∼0.95.

Two Iridium(III) complexes [Ir(ppy)2((mqmaq)]+ (1) and [Ir(bhq)2((mqmaq)]+ (2) {ppy=2-phenylpyridine, bhq= benzo[h]quinoline, mqmaq=2-methyl-3-{(E)-[(quinolin-2-yl)methylidene]amino}quinazolin-4(3H)-one} have been designed, synthesized and structurally characterized. Complex 2 has been structurally characterized by single-crystal X-ray structure determination. The experimentally obtained results of photophysical properties of complexes 1 and 2 well agree with the theoretically calculated results acquired by density functional theory (DFT) studies. The HOMO of complexes 1 and 2 are delimited on the iridium and cyclometalated aromatic ligands, while LUMO, is localized on quinoline-based mqmaq ligand whereas LUMO+1, and LUMO+2 are primarily restricted on cyclometalated ligands. The interaction of complexes with calf thymus DNA (CT-DNA) was investigated by absorption titration and emission titration experiments. Furthermore, the cytotoxicity and cellular localization properties of these complexes towards HeLa cells have been investigated.

The mechanisms of interaction of inorganic complexes with DNA are important in the design and development of new metal-based drug molecules. The limitations of cis-platin have encouraged the design and development of new metal-based target-specific anticancer drugs having reduced side effects. The complex cis-dichloridobis(1,2,5-thiadiazolo[3,4-f][1,10]phenanthroline-κ2 N 1,N 10)copper(II), [CuCl2(C12H6N4S)2], has been synthesized and characterized. The complex crystallizes in the monoclinic space group C2/c. The covalent binding of the complex with DNA was studied by absorption spectroscopy. The anticancer activity of the complex on the Human Lung Carcinoma (A549) cell line was investigated by MTT assay. The complex exhibits higher toxicity than cis-platin and induces an apoptotic mode of cell death.

Proton conducting properties have been investigated in a new Ni(II)-based hydrogen-bonded porous framework synthesized using a urea-fused bipyridine-glycoluril (BPG) tecton. This hydrogen-bonded self-assembled structure encapsulates water molecules in the channels with hydrogen-bonding networks which exhibits a significant temperature dependent proton conductance of 1.5 × 10−4 S cm−1 at 95 °C and 95% RH with a low activation energy (Ea) of 0.54 eV, implying a Grotthuss proton hopping mechanism mediated by hydrogen-bonded water molecules in the channels. In addition, this framework exhibited a very high water uptake under humid conditions. A continuous array of water molecules and chloride ions embedded in the highly hydrophilic porous channels of the hydrogen-bonded framework acts as the proton conducting medium.

Iridium(III) complexes containing quinoline-appended polypyridyl ligands [Ir(ppy)2(qip)]+ (1) and [Ir(bhq)2(qip)]+ (2) {ppy = 2-phenylpyridine, bhq = benzo[h]quinoline, Qip = 2(1H)-quinolinone-3(1H)-imidazo[4,5f][1,10]phenanthrolin-2-yl} have been synthesized and characterized. The structure of complex 2 has been determined by single crystal X-ray crystallography. The experimental photophysical properties of the complexes have been compared with the theoretically obtained results by density functional theory (DFT) and time-dependent density functional theory (TD-DFT) studies. The HOMO of the complexes is mainly localized on the iridium atom while the LUMO is mainly localized on the proximal position of the N–N donor polypyridyl ligand and the LUMO+1 is localized on the distal portion of the N–N donor polypyridyl ligand. The binding of complexes to double-stranded calf thymus DNA (CT-DNA) has been investigated by absorption and emission spectroscopic techniques. The electrophoretic mobility shift assay of plasmid DNA in the presence of complexes shows DNA aggregation at micro-molar concentration. These complexes have low toxicity and their strong intracellular luminescence highlights their potential as theragnostic agents.

The chiral tetradentate N4-donor ligand, 1-methyl-2-({(S)-2-[(S)-1-(1-methylbenzimidazol-2-yl methyl)pyrrolidin-2-yl]pyrrolidin-1-yl}methyl) benzimidazole (S,S-PDBzL), based on a chiral dipyrrolidine backbone, has been synthesized and its corresponding Fe(ii) complex has been prepared and characterized. The X-ray structure of the complex reveals that the Fe(ii) ion is in a distorted octahedral coordination environment with two cis-oriented coordination sites occupied by (labile) triflate anions. The ability of the iron complex to catalyze asymmetric epoxidation reactions of olefins with H2O2 was investigated, using 2-cyclohexen-1-one, 2-cyclopenten-1-one, cis-β-methylstyrene, isophorone, chalcones and tetralones as substrates. Different carboxylic acids were used as additives to enhance yields and enantioselectivities, and 2-ethylhexanoic acid was found to give the best results. The catalysis results indicate that the Fe(ii) complex is capable of effecting comparatively high enantioselectivities (80%) in the epoxidation reactions.

The ligand 3,5-di-tert-butyl-2-hydroxy-N'-((2-oxo-1,2-dihydroquinolin-3-yl)methylene)benzohydrazide (H2L) and its Co(II), Ni(II), Cu(II), Zn(II) complexes were synthesized. The ligand and its complexes were characterized by various spectro-analytical techniques including IR, 1H NMR, 13C NMR, EPR, electronic spectroscopy, and elemental analysis. In addition, the molecular structures of H2L, [CoII(HL)2] (1), [NiII(HL)2] (2), [CuII(HL)(Cl)(CH3OH)] (3), and [CuII(HL)(H2O)(CH3OH)].ClO4 (4) were unambiguously established using single-crystal X-ray structure determination. However, the Zn(II) complex was characterized based on the IR, NMR and elemental analysis and the 6-coordinate with a 1:2 (M:L) ratio was proposed with the molecular formula [ZnII(HL)2)] (5). The synthesized compounds were investigated for antimicrobial and antitubercular activities. The copper(II) complex 4, has shown the lowest MIC of 0.4 µg/mL, against the gram-positive S. Aureus microorganism, which was better than the ligand and the standard Ciprofloxacin drug. Except for the complex 3, the ligand and rest of its complexes exhibited better activity against gram-negative, E. Coli with the MIC values ranging from 0.4 − 0.8 µg/mL and were much better than the standard Ciprofloxacin drug

Presence of collinearity among the explanatory variables results in larger standard errors of parameters estimated. When multicollinearity is present among the explanatory variables, the or...

The estimation of parameters of the log normal distribution based on complete and censored samples are considered in the literature. In this article, the problem of estimating the parameters of log normal mixture model is considered. The Expectation Maximization algorithm is used to obtain maximum likelihood estimators for the parameters, as the likelihood equation does not yield closed form expression. The standard errors of the estimates are obtained. The methodology developed here is then illustrated through simulation studies. The confidence interval based on large-sample theory is obtained.

A mixed ligand copper(II) complex [Cu(naph)(bpy)]NO3•H2O, where, naph = 1-formylnaphthalen-2-olate and bpy= 2,2′-bipyridine has been synthesized and characterized by spectroscopic techniques and finally the structure was confirmed by X-ray diffraction studies. The compound crystallized in monoclinic space group P21/n. The geometry around copper center is square-pyramidal with an N2O3 donor set involving coordination from two nitrogen's of 2,2′-bipyridine, two oxygen's from 1-formylnaphthalen-2-olate and one oxygen from nitrate anion. The intermolecular hydrogen bonding between the oxygen's of coordinated nitrate anion/water of crystallization and hydrogens of aromatic moiety / water of crystallization results in the formation of 3D supramolecular architecture that stabilizes the crystal structure. The bright larger red spots on the Hirshfeld surface indicate the presence of C–H…O interactions between the aromatic CH groups of 2,2′-bipyridine and the apically coordinated oxygen atom of the NO3.

The chiral tetradentate N4-donor ligand, 1-methyl-2-({(S)-2-[(S)-1-(1-methylbenzimidazol-2-yl methyl)pyrrolidin-2-yl]pyrrolidin-1-yl}methyl) benzimidazole (S,S-PDBzL), based on a chiral dipyrrolidine backbone, has been synthesized and its corresponding Fe(II) complex has been prepared and characterized. The X-ray structure of the complex reveals that the Fe(II) ion is in a distorted octahedral coordination environment with two cis-oriented coordination sites occupied by (labile) triflate anions. The ability of the iron complex to catalyze asymmetric epoxidation reactions of olefins with H2O2 was investigated, using 2-cyclohexen-1-one, 2-cyclopenten-1-one, cis-β-methylstyrene, isophorone, chalcones and tetralones as substrates. Different carboxylic acids were used as additives to enhance yields and enantioselectivities, and 2-ethylhexanoic acid was found to give the best results. The catalysis results indicate that the Fe(II) complex is capable of effecting comparatively high enantioselectivities (>80%) in the epoxidation reactions The research has been carried out within the frameworks of the International Research Training Group Metal sites in biomolecules: structures, regulation and mechanisms (http://www.biometals.eu), the Marie Sklodowska-Curie Innovative Training Network MSCAITN-2015-ETN 675020 and COST Action CM1003. M. M. thanks the European Commission for an Erasmus Mundus fellowship

A colorimetric probe L based on rhodamine was designed and synthesized. It exhibits very high sensitivity and selectivity towards Cu2+ in an aqueous medium with a color change from colorless to pink. The competitive experiments of probe L showed excellent colorimetric selectivity for Cu2+ over other metal ions. The recognizing behavior of L has been investigated both experimentally and computationally. The mechanism of L for sensing Cu2+ has been demonstrated by IR, ESI-MS, density functional theory calculation and time-dependent density functional theory calculations.

Free radical generation is an inevitable consequence of aerobic existence and is implicated in a wide variety of pathological conditions including cancer, cardiovascular disease, ageing and neurodegenerative disorder. Free radicals can, however, be used to our advantage since their production is catalysed by synthetic inorganic molecules—termed artificial metallonucleases—that cut DNA strands by oxidative cleavage reactions. Here, we report the rational design and DNA binding interactions of a novel di-Cu2+ artificial metallonuclease [Cu2(tetra-(2-pyridyl)-NMe-naphthalene)Cl4] (Cu2TPNap). Cu2TPNap is a high-affinity binder of duplex DNA with an apparent binding constant (Kapp) of 107 M(bp)−1. The agent binds non-intercalatively in the major groove causing condensation and G-C specific destabilization. Artificial metallonuclease activity occurs in the absence of exogenous reductant, is dependent on superoxide and hydrogen peroxide, and gives rise to single strand DNA breaks. Pre-associative molecular docking studies with the 8-mer d(GGGGCCCC)2, a model for poly[d(G-C)2], identified selective major groove incorporation of the complex with ancillary Cu2+-phosphate backbone binding. Molecular mechanics methods then showed the d(GGGGCCCC)2 adduct to relax about the complex and this interaction is supported by UV melting experiments where poly[d(G-C)2] is selectively destabilized. A.K. and Z.M. acknowledge funding from Science Foundation Ireland Career Development Award (SFI-CDA) [15/CDA/3648]; Marie Skłodowska-Curie Innovative Training Network (ITN) ClickGene [H2020-MSCA-ITN-2014-642023]; Circular dichroism analysis was carried out at the Nano Research Facility in Dublin City University which was funded under the Programme for Research in Third Level Institutions (PRTLI) Cycle 5. The PRTLI is co-funded through the European Regional Development Fund (ERDF), part of the European Union Structural Funds Programme 2011–2015. D.M. acknowledges funding from the European Commission [Marie Curie FP7-IEF]. Funding for open access charge: H2020 Marie Skłodowska-Curie Actions. The authors wish to acknowledge the DJEI/DES/SFI/HEA Irish Centre for High-End Computing (ICHEC) for the provision of computational facilities and support. This work was also supported by the Synthesis and Solid-State Pharmaceutical Centre (SSPC) and Science Foundation Ireland (SFI) under grant number 12/RC/2275. peer-reviewed

Complexes of the type [Ru(N–N)2(tdzp)]Cl2, where N–N is 2,2′-bipyridine (bpy) (1), 1,10-phenathroline (phen) (2), dipyrido[3,2-d:2′,3-f] quinoxaline (dpq) (3), which incorporate the [1,2,5]-thiadiazolo-[3,4-f]-[1,10]-phenanthroline (tdzp) ligand, have been synthesized and characterized by IR, 1H-NMR, 13C-NMR, ESI-MS, elemental analysis, UV-Visible and luminescence spectroscopy. The molecular structure of complex 2 is confirmed by single crystal X-ray structure determination. A two-dimensional cyclic water–chloride anionic {[(H2O)10(Cl)2]2−}n network has been structurally identified in a hydrophobic matrix of 2. Interaction of these complexes with Calf Thymus DNA (CT-DNA) was explored by electronic absorption and emission spectroscopy and circular dichroism spectroscopy. The nucleolytic cleavage activity of complexes 1–3 has been carried out on double stranded circular plasmid pBR322 DNA by gel electrophoresis experiments. The cytotoxicity of the complexes against a cancer cell line has been studied by MTT assay and cellular localization of complexes within the cells has been monitored by fluorescence microscopy. Notably, 1–3 exhibit potent antiproliferative activities against a panel of human cancer cell line.

Two phosphorescent cyclometalated iridium(III)-triptycenyl-1,10-phenanthroline complexes [Ir(ppy)2(tpt-phen)]+ (1) and [Ir(bhq)2(tpt-phen)]+ (2) {ppy=2-phenylpyridine, bhq=Benzo[h]quinoline, tpt-phen=triptycenyl-1,10-phenanthroline} have been synthesized and structurally characterized. The structure of complex 2 has been studied by single crystal X-ray crystallography. The photophysical properties of complexes in a different solvent have also been investigated. The binding of complexes to the double stranded calf thymus (CT-DNA) has been investigated by spectroscopic techniques. These complexes condense originally circular plasmid DNA into particulate structures. The DNA-condensation induced by these complexes have been investigated by electrophoretic mobilty shift assay, dynamic light scattering, and fluorescence microscopy. Furthermore, the cytotoxicity of these complexes towards HeLa cells have been studied and their cellular localisation properties have been investigated by fluorescence microscopy.

Three water-soluble tris-heteroleptic ruthenium(II) polypyridyl complexes [Ru(bpy)(phen)(bpg)]2+ (1), [Ru(bpy)(dppz)(bpg)]2+ (2), and [Ru(phen)(dppz)(bpg)]2+ (3) (where bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline, dppz = dipyrido[3,2-a:2′,3′-c] phenazine, bpg = 4b,5,7,7a-tetrahydro-4b,7a-epiminomethanoimino-6H-imidazo[4,5-f] [1,10] phenanthroline-6,13-dione) have been synthesized and characterized. Molecular structures of complexes 1 and 3 are confirmed by single crystal X-ray structure determination. Interaction of complexes 1–3 with DNA is explored by various spectroscopic techniques. The complexes 1–3 show solvent dependent photophysical properties. Complexes 2 and 3 show extensive “molecular light switch” effect for DNA. The complexes 1–3 are low toxic towards HeLa (human cervical cancer) and HL-60 (human promyelocytic leukemia) cell lines. Further, the cellular uptake of complexes 2 and 3 by cells shows that complexes mainly localised on the nucleus of the cells.

cis-Pt(dafone)Cl2 has been synthesized and crystallographically characterized. Dafone, in spite of its long chelate bite, binds in a symmetrical fashion with longer Pt–N distances compared to its phen (1,10-phenanthroline) and bipy (2,2′-bipyridine) analogs. The covalent binding of the complex with DNA was explored by absorption and emission spectroscopy, and electrophoretic mobility shift assay. Cytotoxicity studies of the complex against human cervical carcinoma cells (HeLa) and immortal human keratinocyte (HaCat) cell lines indicate that it has an activity comparable to that of the famed drug, cis-platin.

Two ruthenium(II) polypyridyl complexes [Ru(phen) 3 ] 2+ ( 1 ) and [Ru(phen) 2 (bxbg)] 2+ ( 2 ) (where phen = 1,10 phenanthroline, bxbg = bis(o-xylene)bipyridine glycoluril) have been evaluated for acetylcholinesterase (AChE) and Amyloid-β peptide (Aβ) aggregation inhibition. Complex 2 exhibits higher potency of AChE inhibition and kinetics and molecular modeling studies indicate that ancillary ligand plays significant role in inhibitory potency exhibited by complex 2 . The inhibitory effect of these complexes on Aβ (1–40) aggregation is investigated using Thioflavin T fluorescence and Transmission Electron Microscopy. Both complexes efficiently inhibit Aβ (1–40) aggregation and are negligibly toxic to human neuroblastoma cells. This is the first demonstration that ruthenium(II) polypyridyl complexes simultaneously inhibit AChE and Aβ aggregation.

Two new luminescent ruthenium(II) polypyridyl complexes, [Ru(bpy)2 (tpt-phen)]Cl2 (1; bpy=2,2'-bipyridine, tpt-phen=triptycenyl-1,10-phenanthroline) and [Ru(phen)2 (tpt-phen)]Cl2 (2; phen=1,10-phenanthroline), have been developed as potential nonviral vectors for DNA delivery. Photophysical and electrochemical properties of the complexes have been investigated and corroborated with electronic structure calculations. DNA condensation by these complexes has been investigated by UV/Vis and emission spectroscopy, circular dichroism spectroscopy, atomic force microscopy, dynamic light scattering, confocal microscopy, and electrophoretic mobility studies. These complexes interact with DNA and efficiently condense DNA into globular nanoparticles that are taken up efficiently by HeLa cells. DNA cleavage inability and biocompatibility of complexes have been explored. Both complexes have good gene transfection abilities.

Two mononuclear fluorophore-labeled copper(II) complexes [Cu(nip)(acac)](+)(2) and [Cu(nip)2](2+) (3), where fluorophore is 2-(naphthalen-1-yl)-1H-imidazo[4,5-f][1,10]phenanthroline (nip) (1) and acac is acetylacetone, have been synthesized and characterized by various techniques. The ligand 1 and complex 2 are structurally characterized by single-crystal X-ray diffraction. The coordination geometries around the copper are square planar in solid as well as solution state as evidenced by electron paramagnetic resonance (EPR) spectroscopy. The density functional calculations carried out on 1-3 have shown that electron-rich regions in the highest occupied orbital are localized on the naphthalene and partly on the phenanthroline moiety. Both complexes 2 and 3 in dimethyl sulfoxide (DMSO) exhibit near square planar structure around the metal ion in their ground state. Time-dependent density functional theory (TD-DFT) calculations reveal that Cu(II) ion in complex 2 shows tetrahedral coordination around the metal while 3 retains its square planar geometry in the lowest excited state. The interaction of complexes with calf-thymus DNA (CT DNA) has been explored by using absorption, emission, thermal denaturation, and viscosity studies, and the intercalating mode of DNA binding has been proposed. The complexes cleave DNA oxidatively without any exogenous additives. The protein binding ability has been monitored by quenching of tryptophan emission in the presence of complexes using bovine serum albumin (BSA) as model protein. The compounds showed dynamic quenching behavior. Further, the anticancer activity of the complexes on MCF-7 (human breast cancer), HeLa (human cervical cancer), HL-60 (human promyelocytic leukemia), and MCF-12A (normal epithelial) cell lines has been studied. It has been observed that 3 exhibits higher cytotoxicity than 2, and the cells undergo apoptotic cell death.

Complexes of the type [Ru(N-N)(2)(bxbg)]Cl(2) where N-N is 2,2'-bipyridine (bpy) (1), 1,10-phenanthroline (phen) (2), dipyrido [3,2-d:2',3f] quinoxaline (dpq) (3), and dipyrido[3,2-a:2',3'-c]phenazine (dppz) (4) which incorporate the bis(o-xylene)bipyridine glycoluril (bxbg) as the ancillary ligand have been synthesized and characterized by IR, NMR, UV-visible, luminescence, ESI-MS, cyclic voltammetry, and spectroelectrochemistry. The bis(o-xylene)bipyridine glycoluril initiates a head to head association which act as the nucleation point for the further growth in two direction by head-to-head and tail-to-tail self-association resulting in formation of aggregates in water which have been investigated by (1)H NMR, NOESY, steady state luminescence dilution experiments, and electron microscopy studies. The self-association has been confirmed by single crystal X-ray analysis of complex 2. Electrochemical and spectroelectrochemical studies in acetonitrile show that these complexes undergo reversible one electron oxidation from Ru(II) to Ru(III). The binding of these complexes with calf thymus DNA (CT-DNA) has been studied by absorption titration, steady-state and time-resolved emission measurement experiments, to investigate the influence of the ancillary ligand. The binding ability of these complexes to DNA is dependent on the planarity of the intercalative polypyridyl ligand which is further affected by the bis(o-xylene)bipyridine glycoluril ancillary ligand.

The meta-pyridine appended bidentate ligands L1, L2 and L3, crafted with flexible polyether spacer, are prepared by condensation of nicotinoyl chloride hydrochloride with di, tri-, and tetra-ethylene glycol, respectively. Self-assembled palladium(II) based mononuclear molecular loops of general formula cis-[Pd(N-N)(L)](NO 3)2 are obtained exclusively by combining 1 equiv. of a ligand L with 1 equiv. of a cis-protected palladium(II) component, cis-[Pd(N-N)(NO3)2]. Complexation of 2 equiv. of L with 1 equiv. of palladium(II) nitrate also resulted mononuclear complexes, i.e. [Pd(L)2](NO3)2. The ligands used in the complexation reactions are L1, L2 and L3 where as the cis-protecting units N-N employed are ethylenediamine (en), 2,2?-bipyridine (bpy), and 1,10-phenanthroline (phen). Thus 12 number of mononuclear complexes are prepared using all possible combination of above mentioned three number of ligands and four variety of palladium(II) components. Large chelate rings are realized irrespective of the spacer length or type of palladium(II) component used. All the resulted compounds are characterized by NMR and ESI-MS techniques and the structure of cis-[Pd(en)(L1)] (NO3)2, cis-[Pd(bpy)(L1)](NO3) 2 and [Pd(L3)2](NO3)2 are confirmed by single crystal X-ray diffraction. The binding abilities of cis-[Pd(phen)(L1)](NO3)2, cis-[Pd(phen)(L 2)](NO3)2 and cis-[Pd(phen)(L 3)](NO3)2 with DNA has been investigated by ethidium bromide displacement assay and gel electrophoresis. � 2013 Elsevier B.V. All rights reserved.

Complexes of the type [Ru(bxbg)(2) (N-N)](2+), where N-N denotes 2,2'-bipyridine (bpy) (1), 1,10-phenanthroline (phen) (2), dipyrido[3,2-d:2',3-f] quinoxaline (dpq) (3), and dipyrido[3,2-a:2',3'-c]phenazine (dppz) (4), incorporating bis(o-xylene)bipyridine-glycoluril (bxbg) as an ancillary "molecular clip" ligand, have been synthesized and characterized. These ruthenium(II) complexes of bis(o-xylene)bipyridine-glycoluril self-associate in water through specific molecular recognition processes to form polycationic arrays. These arrays containing electrostatic binders as well as intercalator ligands at micromolar doses rapidly condense free DNA into globular nanoparticles of various sizes. The DNA condensation induced by these complexes has been investigated by electrophoretic mobility assay, dynamic light scattering, and transmission electron microscopy. The cellular uptake of complex-DNA condensates and the low cytotoxicity of these complexes satisfy the requirements of a gene vector.

Two novel water soluble ruthenium(II) complexes [Ru(bpy)(2)(bqbg)](2+) and [Ru(phen)(2)(bqbg)](2+) have been structurally characterized and their DNA condensation activity, cytotoxicity, and cellular uptake studies of DNA condensates as potential non-viral DNA carriers were evaluated.