Synthesis and characterization of physical crosslinking systems based on cyclodextrin inclusion/host‐guest complexation

New supramolecular assemblies based on cyclodextrin and adamantane were prepared. Two methacrylate monomers bearing cyclodextrin and adamantane were synthesized, and copolymerized with poly(ethylene glycol) methyl ether methacrylate, (PEGMA, 300 g/mol), by free radical polymerization. Copolymers bearing pendent cyclodextrin and adamantane were characterized by NMR, FTIR, TGA, SEC, Differential scanning calorimetry (DSC), and UV‐visible spectrophotometer. All copolymers showed two distinct glass transitions. The specific interaction between pendent adamantyl and cyclodextrin was examined by ¹H‐NMR. The viscoelastic properties of supramolecular assemblies were investigated with frequency and temperature sweep experiments. The specific host‐guest interaction between pendent adamantyl and cyclodextrin lead to large increases of the viscosity; and depending on the concentration of these groups, also to gel formation. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 581–592, 2010     

Conjugated Polyelectrolyte‐Induced Self‐Assembly of Alkynylplatinum(II) 2,6‐Bis(benzimidazol‐2′‐yl)pyridine Complexes

Water‐soluble cationic alkynylplatinum(II) 2,6‐bis(benzimidazol‐2′‐yl)pyridine (bzimpy) complexes have been demonstrated to undergo supramolecular assembly with anionic polyelectrolytes in aqueous buffer solution. Metal–metal‐to‐ligand charge transfer (MMLCT) absorptions and triplet MMLCT (³MMLCT) emissions have been found in UV/Vis absorption and emission spectra of the electrostatic assembly of the complexes with non‐conjugated polyelectrolytes, driven by Pt???Pt and π–π interactions among the complex molecules. Interestingly, the two‐component ensemble formed by [Pt(bzimpy‐Et){C?CC₆H₄(CH₂NMe₃‐4)}]Cl₂ ( 1 ) with para‐linked conjugated polyelectrolyte (CPE), PPE‐SO₃^?, shows significantly different photophysical properties from that of the ensemble formed by 1 with meta‐linked CPE, mPPE‐Ala. The helical conformation of mPPE‐Ala allows the formation of strong mPPE‐Ala– 1 aggregates with Pt???Pt, electrostatic, and π–π interactions, as revealed by the large Stern–Volmer constant at low concentrations of 1 . Together with the reasonably large Förster radius, large HOMO–LUMO gap and high triplet state energy of mPPE‐Ala to minimize both photo‐induced charge transfer (PCT) and Dexter triplet energy back‐transfer (TEBT) quenching of the emission of 1 , efficient Förster resonance energy transfer (FRET) from mPPE‐Ala to aggregated 1 molecules and strong ³MMLCT emission have been found, while the less strong PPE‐SO₃^?– 1 aggregates and probably more efficient PCT and Dexter TEBT quenching would account for the lack of ³MMLCT emission in the PPE‐SO₃^?– 1 ensemble.     

Interaction of Fluorescently Labeled Triethyleneglycol and Peptide Derivatives with β‐Cyclodextrin

A triethyleneglycol (TEG) chain, a linear peptide, and a cyclic peptide labeled with 7‐methoxycoumarin‐3‐carboxylic acid (MC) and 7‐diethylaminocoumarin‐3‐carboxylic acid (DAC) were used to thoroughly study Förster resonance energy transfer (FRET) in inclusion complexes. ¹H NMR evidence was given for the formation of a 1:1 inclusion complex between β‐cyclodextrin (β‐CD) and the fluorophore moieties of model compounds. The binding constant was 20 times higher for DAC than for MC derivatives. Molecular modeling provided additional information. The UV/Vis absorption and fluorescence properties were studied and the energy transfer process was quantified. Fluorescence quenching was particularly strong for the peptide derivatives. The presence of β‐CDs reduced the FRET efficiency slightly. Dye‐labeled peptide derivatives can thus be used to form inclusion complexes with β‐CDs and retain most of their FRET properties. This paves the way for their subsequent use in analytical devices that are designed to measure the activity of matrix metalloproteinases.     

Assembly of Palladium(II) and Platinum(II) Metallo‐Rectangles with a Guanosine‐Substituted Terpyridine and Study of Their Interactions with Quadruplex DNA

Two novel [2+2] metallo‐assemblies based on a guanosine‐substituted terpyridine ligand ( 1 ) coordinated to palladium(II) ( 2 a ) and platinum(II) ( 2 b ) are reported. These supramolecular assemblies have been fully characterized by NMR spectroscopy, ESI mass spectrometry and elemental analyses. The palladium(II) complex ( 2 a ) has also been characterized by single crystal X‐ray diffraction studies confirming that the system is a [2+2] metallo‐rectangle in the solid state. The stabilities of these [2+2] assemblies in solution have been confirmed by DOSY studies as well as by variable temperature ¹H NMR spectroscopy. The ability of these dinuclear complexes to interact with quadruplex and duplex DNA was investigated by fluorescent intercalator displacement (FID) assays, fluorescence resonance energy transfer (FRET) melting studies, and electrospray mass spectrometry (ESI‐MS). These studies have shown that both these assemblies interact selectively with quadruplex DNA (human telomeric DNA and the G‐rich promoter region of c‐myc oncogene) over duplex DNA, and are able to induce dimerization of parallel G‐quadruplex structures.     

Efficient energy transfer between amphiphilic dendrimers with oligo(p‐phenylenevinylene) core branches and oligo(ethylene oxide) termini in micelles

The efficient fluorescence resonance energy transfer (FRET) between amphiphilic dendrimers with oligo(p‐phenylenevinylene) core branches and oligo(ethylene oxide) termini have been observed in micelles. All dendrimers show the critical micelle concentration and lower critical solution temperature as well as fluorescent emission. Tailoring electronic structures of the conjugated amphiphiles for FRET have been conveniently achieved by varying the branch number and/or the conjugated core structure. The Stern‐Volmer constants (K_SV) for FRET were found to be 4.51 × 10^?5 and 8.78 × 10^?5 M for Den 30–40 and Den 50–40, respectively. The effects external stimuli such as solvent and temperature on FRET have been also investigated. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

β‐Cyclodextrin‐Functionalized Gold Nanoparticles/Poly(L‐cysteine) Modified Glassy Carbon Electrode for Sensitive Determination of Metronidazole

A simple electrochemical method was developed to determine metronidazole based on β‐cyclodextrin‐functionalized gold nanoparticles/poly(L ‐cysteine) modified glassy carbon electrode (β‐CD‐GNPs/poly(L ‐cys)/GCE). The electropolymerized film of poly(L ‐cys) provides a stable matrix for the fabrication of a sensing interface. β‐CD‐GNPs can form inclusion complexes with metronidazole and act as a modifier with catalytic function. The modified electrode exhibited excellent electrocatalytic activity towards metronidazole. The reaction of metronidazole at the modified electrode was an irreversible process controlled by diffusion. Under optimum experimental conditions, the logarithm of catalytic currents shows a good linear relationship with that of the metronidazole concentration in the range of 0.1–600 µmol/L with a low detection limit of 14 nmol/L. In addition, the modified electrode exhibited satisfactory stability, sensitivity and reproducibility, and could be applied to the determination of metronidazole in an injection solution.     

Synthesis,Characterization, Self‐Assembly,Gelation, Morphology and Computational Studies of Alkynylgold(III) Complexes of 2,6‐Bis(benzimidazol‐2′‐yl)pyridine Derivatives

A novel class of alkynylgold(III) complexes of the dianionic ligands derived from 2,6‐bis(benzimidazol‐2′‐yl)pyridine (H₂bzimpy) derivatives has been synthesized and characterized. The structure of one of the complexes has also been determined by X‐ray crystallography. Electronic absorption studies showed low‐energy absorption bands at 378–466 nm, which are tentatively assigned as metal‐perturbed π–π* intraligand transitions of the bzimpy^2? ligands. A computational study has been performed to provide further insights into the nature of the electronic transitions for this class of complexes. One of the complexes has been found to show gelation properties, driven by π–π and hydrophobic–hydrophobic interactions. This complex exhibited concentration‐ and temperature‐dependent ¹H NMR spectra. The morphology of the gel has been characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM).     

Synthesis,Characterization, and Antibacterial Activities of Organotin(IV) Complexes with 2‐Acetylpyridine‐N(4)‐cyclohexylthiosemicarbazone (HAPCT)

The reaction of 2‐acetylpyridine‐N(4)‐cyclohexylthiosemicarbazone [(HAPCT), ( 1 )] ligand with organotin(IV) chloride(s) afforded the five new organotin(IV) complexes: [MeSnCl₂(APCT)] ( 2 ), [BuSnCl₂(APCT)] ( 3 ), [PhSnCl₂(APCT)] ( 4 ), [Me₂SnCl(APCT)] ( 5 ), and [Ph₂SnCl(APCT)] ( 6 ). The ligand ( 1 ) and its organotin(IV) complexes ( 2–6 ) have been synthesized and characterized by CHN analyses, molar conductivity, UV–vis, FT IR, ¹H, ¹³C, and ¹¹⁹Sn NMR spectral studies. The single crystal X‐ray diffraction studies indicated that [PhSnCl₂(APCT)] ( 4 ) is six coordinated and strongly adopts a distorted octahedral configuration with the coordination through pyridine‐N, azomethine‐N, and thiolato‐S atoms of the ligand. The compound crystallizes into a monoclinic lattice with the space group P21/n. The ligand ( 1 ) and its organotin(IV) complexes ( 2–6 ) were assayed for in vitro antibacterial activity against Staphylococcus aureus, Escherichia coli, Enterobacter aerogenes, and Salmonella typhi. The screening results have shown that the organotin(IV) complexes ( 2–6 ) have better antibacterial activity than the free ligand. Furthermore, it has been shown that the diphenyltin(IV) derivative ( 6 ) exhibits significantly better activities than the other organotin(IV) derivatives ( 2–5 ). © 2012 Wiley Periodicals, Inc. Heteroatom Chem 24:43–52, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.21061     

Synthesis,Spectral, Thermal and Biological Studies of Mn(II), Co(II), Ni(II) and Cu(II) Complexes with 1‐(((5‐Mercapto‐1H‐1,2,4‐triazol‐3‐yl)imino)‐methyl)naphthalene‐2‐ol

Mn(II), Co(II), Ni(II) and Cu(II) complexes of 5‐mercapto‐1,2,4‐triazol‐3‐imine‐2′‐hydroxynaphthaline have been synthesized and characterized by elemental analysis, IR, ¹H NMR, EI‐mass, UV‐Vis, and ESR (electron spin resonance) spectra, molar conductance, magnetic moment measurements, DC conductivity and thermogravimetric analysis. IR spectra confirm that the ligand molecule existed in both thione and thiole forms. The molar conductance values indicate the complexes are nonelectrolyte. The magnetic moment values of the complexes display paramagnetic behavior. All studies confirm the formation of an octahedral geometry for complex 1 and the other complexes have tetrahedral geometrical structures. The structures of the complexes have also been theoretically studied by using the molecular mechanic calculations by the hyperchem. 8.03 molecular modeling program which confirm the proposed structures. The Schiff‐base ligand and its metal complexes have also been screened for their antimicrobial activities.     

Synthesis,structural features and biochemical activity assessment of N,N′‐bis‐(2‐mercaptophenylimine)‐2,5‐thiophenedicarboxaldehyde Schiff base and its Co(II), Ni(II), Cu(II) and Zn(II) complexes

The tetradentate Schiff base ligand (SB), N,N′‐bis‐(2‐mercaptophenylimine)‐2,5‐thiophenedicarboxaldehyde was prepared via condensation of 2,5‐thiophene‐dicarboxaldehyde with 2‐aminothiophenol in a 1:2 molar ratio by conventional method. Additionally, its Co(II), Ni(II), Cu(II) and Zn(II) complexes have been synthesized and fully characterized by elemental analysis, FT‐IR, ¹H NMR, ¹³C NMR, UV–Vis, ESR, ESI‐mass, conductivity and magnetic susceptibility measurements. Spectral studies suggested that, the Schiff base coordinate metal ions through the azomethine N‐ and deprotonated thiol S‐ atoms. Based on UV–Vis absorption and magnetic susceptibility data, tetrahedral geometry was assigned for both Co(II) and Zn(II) complexes, whereas on the other hand, square planar geometry for both Ni(II) and Cu(II) complexes. The Schiff base and its metal complexes were screened for their in vitro antimicrobial activity by minimum inhibitory concentration (MIC) method. Free radical scavenging activity of the novel compounds was determined by elimination of 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radicals. In addition, the interactions of the free ligand and its complexes with calf thymus DNA (CT‐DNA) were explored using absorption, emission and viscosity measurements techniques.     

Noncovalently connected micelles based on a β‐cyclodextrin‐containing polymer and adamantane end‐capped poly(ε‐caprolactone) via host–guest interactions

New random copolymers, poly(N‐vinyl‐2‐pyrrolidone‐co‐mono‐6‐deoxy‐6‐methacrylate ethylamino‐β‐cyclodextrin) (PnvpCD) bearing pendent β‐cyclodextrin (CD) groups were synthesized. PnvpCD formed soluble graft‐like polymer complex with adamantane (AD) end‐capped poly(ε‐caprolactone) (PclAD) in their common solvent N‐methyl‐2‐pyrrolidone driven by the inclusion interactions between the CD and AD groups. The formation of the graft complex has been confirmed by viscometry, dynamic light scattering (DLS), and isothermal titration calorimeter. The graft complex self‐assembled further into noncovalently connected micelles in water, which is a selective solvent for the main chain PnvpCD. Transmission electron microscopy, DLS, and atomic force microscopy have been used to investigate the structure and morphology of the resultant micelles. A unique “multicore” structure of the micelles, in which small PclAD domains scattered within the micelles, was obtained under nonequilibrium conditions in the preparation. However, the micelles prepared in a condition close to equilibrium possess an ordinary core‐shell structure. In both cases, the core and shell are believed to be connected by the AD‐CD inclusion complexation. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4267–4278, 2009     

Core‐Shell Structured Layered Lanthanide‐Organic Complexes with Stilbazolium‐type Dye Encapsulation for Multifunctional Performances

Host‐guest encapsulation of functional organic dye into a porous metal‐organic framework can give rise to the development of new functional materials. In this work, by intercalating the stilbazolium‐type dye (DEAST)I (4′‐diethylamino‐N‐methyl stilbazolium) into four lanthanide layered metal‐organic complexes (Ln‐LMOCs), i. e. {[Ln(BTB)(H₂O)₂]?3(DMF)?2(H₂O)}_n (Ln=La (1), Nd (2), Sm (3), Er (4)), four responsive (DEAST)I@Ln‐LMOC composites have been prepared, serving as multifunctional performance platform. The core–shell structures of (DEAST)I@Ln‐LMOC composites have been fully characterized by IR, UV/Vis, PXRD, SEM, TEM, TGA and ESR. Significantly, after intercalation of dyes, the (DEAST)I@Ln‐LMOC composites exhibit enhanced luminescent sensing properties in detecting Fe³⁺ with much higher water stabilities. The luminescent sensing behavior stems from the fluorescence resonance energy transfer (FRET) from the π‐electron‐rich BTB ligands to the Fe³⁺, and their higher water stabilities are induced by electrostatic interactions and lower porosity. Specially, the characteristic emissions of Sm³⁺ will not be affected after the encapsulation guest dyes, which provide a theoretical guide for the modulation of luminescence devices. Finally, better ion conductivities and diminished photocurrents can be achieved after the embedding of the functional organic dye. In all, the formation of (DEAST)I@Ln‐LMOC composites with core–shell structures can be utilized as a multifunctional platform with good stability.     

Hydrogen‐Bond‐Based Magnetic Exchange Between μ‐Diethylnicotinamide(aqua)bis(X‐salicylato)copper(II) Polymeric Chains

Polymeric salicylatocopper(II) complexes of unusual composition [C u(X‐ sal)₂( μ‐denia)(H₂O)]_n [denia = diethylnicotinamide, and X‐sal = 5‐methylsalicylate ( 1 ), 3‐methylsalicylate ( 2 ), 4‐methoxysalicylate ( 3 ), 3,5‐dichlorosalicylate ( 4 ) and 3,5‐dibromosalicylate ( 5 )] were synthesized and characterized. Magnetic measurements were performed in the temperature range 1.8–300 K. The structural unit of all complexes consists of a Cu^II atom, which is monodentately coordinated by the pair of X‐salicylate anions in trans positions. Water and the diethylnicotinamide ligand occupy the other two basal plane positions of the tetragonal pyramid. The axial positions are occupied by a diethylnicotinamide oxygen atom of neighboring structural units, thus forming a spiral polymeric structure parallel to b axis. Magnetic measurements showed that all complexes 1 – 5 exhibit a susceptibility maximum at about 6–8 K. The obtained data fit to Bleaney–Bowers equation gave singlet‐triplet energy gaps 2J = –8.60 cm^–1 for 1 , 2J = –6.57 cm^–1 for 2 , 2J = –8.57 cm^–1 for 3 , 2J = –6.82 cm^–1 for 4 , and 2J = –6.45 cm^–1 for 5 . The supramolecular structure based on hydrogen bonds [described by supramolecular synthons R₂²(10) and R₂²(12)] is the pathway for antiferromagnetic interactions of the magnetically coupled pairs of copper atoms of neighboring chains within the 2D supramolecular layers. The results of the magnetic measurements suggest involvement of the COO groups in the magnetic interaction pathway for all five complexes.     

Ruthenium(II)–Polyimine–Coumarin Light‐Harvesting Molecular Arrays: Design Rationale and Application for Triplet–Triplet‐Annihilation‐Based Upconversion

Ru^II–bis‐pyridine complexes typically absorb below 450 nm in the UV spectrum and their molar extinction coefficients are only moderate (ε<16 000 M ^?1 cm^?1). Thus, Ru^II–polyimine complexes that show intense visible‐light absorptions are of great interest. However, no effective light‐harvesting ruthenium(II)/organic chromophore arrays have been reported. Herein, we report the first visible‐light‐harvesting Ru^II–coumarin arrays, which absorb at 475 nm (ε up to 63 300 M ^?1 cm^?1, 4‐fold higher than typical Ru^II–polyimine complexes). The donor excited state in these arrays is efficiently converted into an acceptor excited state (i.e., efficient energy‐transfer) without losses in the phosphorescence quantum yield of the acceptor. Based on steady‐state and time‐resolved spectroscopy and DFT calculations, we proposed a general rule for the design of Ru^II–polypyridine–chromophore light‐harvesting arrays, which states that the ¹IL energy level of the ligand must be close to the respective energy level of the metal‐to‐ligand charge‐transfer (M LCT) states. Lower energy levels of ¹IL/³IL than the corresponding ¹M LCT/³M LCT states frustrate the cascade energy‐transfer process and, as a result, the harvested light energy cannot be efficiently transferred to the acceptor. We have also demonstrated that the light‐harvesting effect can be used to improve the upconversion quantum yield to 15.2 % (with 9,10‐diphenylanthracene as a triplet‐acceptor/annihilator), compared to the parent complex without the coumarin subunit, which showed an upconversion quantum yield of only 0.95 %.     

Novel 13,14‐dimethyl‐5,8‐dioxa‐2,11,13,14‐tetraaza‐1,12‐diphosphabicyclo [10.1.1] tetradecane 1,12‐dioxide ligand and its Ni(II), Co(II), and Cu(II) complexes: Synthesis,characterization, antimicrobial,DNA cleavage,and computational studies

A novel diazadiphosphetidine ligand derived from the reaction of 2,4‐dichloro‐1,3‐dimethyl‐1,3,2,4‐diazadiphosphetidine‐2,4‐dioxide and 2,2′‐(ethane‐1,2‐diylbis[oxy])bis(ethan‐1‐amine) and its Ni(II), Cu(II), and Co(II) complexes have been synthesized, characterized by spectroscopic, elemental analyses, magnetic susceptibility, and conductivity methods, and screened for antimicrobial, DNA binding, and cleavage properties. Spectroscopic analysis and elemental analyses indicate the formula [M(H₂L)Cl₂] for the Cu(II), Co(II), Ni(II), and Zn(II) complexes and octahedral geometry for all the complexes. The non‐electrolytic nature of the complexes in dimethyl sulfoxide (DMSO) was confirmed by their molar conductance values, which are in the range 12.32–6.73 Ω^?1 cm² mol^?1. Computational studies have been carried out at the density functional theory (DFT)‐B3LYP/6‐31G(d) level of theory on the structural and spectroscopic properties of diazadiphosphetidine H₂L and its binuclear Cu(II), Co(II), Ni(II), and Zn(II) complexes. Six tautomers and geometrical isomers of the diazadiphosphetidine ligand were confirmed using semiempirical AM1 and DFT method from DMOL³ calculations. The copper complex had the best antibacterial activity against Staphylococcus aureus (ATCC 29213). DNA cleavage activities of the compounds, evaluated on pBR322 DNA by agarose gel electrophoresis in the presence and absence of an oxidant (H₂O₂) and a free‐radical scavenger (DMSO), indicated no activity for the ligand and moderate activity for the complexes, with the copper complex cleaving pBR322 DNA more efficiently in the presence of H₂O₂.     

G‐Tetraplex‐Induced FRET within Telomeric Repeat Sequences Using PyA‐PerA as Energy Donor–Acceptor Pair

G‐tetraplex induced fluorescence resonance energy transfer (FRET) within telomeric repeat sequences has been studied using a nucleoside‐tethered FRET pair embedded in the human telomeric G‐quadruplex forming sequence (5′‐A GGG TT ^Py A GGG TT ^Per A GGG TTA GGG‐3′, Py=pyrene, Per=perylene). Conformational change from a single strand to an anti‐parallel G‐quadruplex leads to FRET from energy donor ( ^Py A ) to acceptor ( ^Per A ). The distance between the FRET donor/acceptor partners was controlled by changing the number of G‐quartet spacer units. The FRET efficiency decreases with increase in G‐quartet units. Overall findings indicate that this could be further used for the development of FRET‐based sensing and measurement techniques.     

Synthesis,cytotoxicity and anti‐metastatic properties of new pyridyl–thiazole arene ruthenium(II) complexes

A series of novel ruthenium(II)–cymene complexes ( 1 – 8 ) containing substituted pyridyl–thiazole ligands, [Ru(η⁶‐p‐cymene)(L)Cl]Cl (L = N,N‐chelating derivatives), have been synthesized and characterized using elemental analysis, infrared, ¹H NMR and ¹³C NMR spectroscopies and mass spectrometry. All these complexes not only display marked cytotoxicity in vitro against three different human cancer cell lines (HeLa, A549 and MDA‐MB‐231), but also exhibit promising anti‐metastatic activity at sub‐cytotoxic concentrations. Cell cycle analysis shows that the ruthenium(II) complex‐induced growth inhibition was mainly caused by S‐phase cell cycle arrest. Further protein level analysis suggests that compound 5 may exert antitumor activity via a p53‐independent mechanism.     

Platinum (II) N‐heterocyclic carbene complexes: Synthesis,characterization and cytotoxic properties

Platinum (II) complexes bearing N‐heterocyclic carbene (NHC) ligands have been widely used in catalytic chemistry, but there are very few reports of biological properties of this type of complexes. A series of [PtCl₂(NHC)(PEt₃)] complexes were synthesized. The structures of all compounds were characterized by ¹H‐NMR, ¹³C‐NMR, IR and elemental analysis techniques, which supported the proposed structures. The single crystal structures of complexes 1a and 1e were determined. The title complexes show slightly distorted square‐planar coordination around the platinum (II) metal center. The cytotoxic properties of the platinum (II)–NHC complexes have been assessed in various human cancer lines, including cisplatin‐sensitive and resistant cells. IC₅₀ values of these four complexes were determined by the MTS‐based assay on three human cell lines—brain (SHSY5Y), colon (HTC116) and liver (HEP3B). These complexes have been highlighted cancer therapeutic agent with unique structures and functions.     

Quadruplex DNA‐Stabilising Dinuclear Platinum(II) Terpyridine Complexes with Flexible Linkers

Four dinuclear terpyridineplatinum(II) (Pt–terpy) complexes were investigated for interactions with G‐quadruplex DNA (QDNA) and duplex DNA (dsDNA) by synchrotron radiation circular dichroism (SRCD), fluorescent intercalator displacement (FID) assays and fluorescence resonance energy transfer (FRET) melting studies. Additionally, computational docking studies were undertaken to provide insight into potential binding modes for these complexes. The complexes demonstrated the ability to increase the melting temperature of various QDNA motifs by up to 17 °C and maintain this in up to a 600‐fold excess of dsDNA. This study demonstrates that dinuclear Pt–terpy complexes stabilise QDNA and have a high degree of selectivity for QDNA over dsDNA.     

Pseudohalide‐directed Assembly of Two Zinc(II) Coordination Polymers with a 3,4‐Bis(3‐pyridyl)‐5‐(4‐pyridyl)‐1,2,4‐triazole Tecton

The zinc(II) pseudohalide complexes {[Zn(L³³⁴)(SCN)₂(H₂O)](H₂O)₂}_n ( 1 ) and [Zn(L³³⁴)(dca)₂]_n ( 2 ) were synthesized and characterized using the ligand 3,4‐bis(3‐pyridyl)‐5‐(4‐pyridyl)‐1,2,4‐triazole (L³³⁴) and ZnCl₂ in presence of thiocyanate (SCN^–) and dicynamide [dca, N(CN)₂^–] respectively. Single‐crystal X‐ray structural analysis revealed that the central Zn^II atoms in both complexes have similar octahedral arrangement. Compound 1 has a 2D sheet structure bridged by bidentate L³³⁴ and double μ_N,S‐thiocyanate anions, whereas complex 2 , incorporating with two monodentate dicynamide anions, displays a two‐dimensional coordination framework bridged by tetradentate L³³⁴ ligand. Structural analysis demonstrated that the influence of pseudohalide anions plays an important role in determining the resultant structure. Both complexes were characterized by IR spectroscopy, microanalysis, and powder X‐ray diffraction techniques. In addition, the solid fluorescence and thermal stability properties of both complexes were investigated.