Advanced supramolecular initiator for nitroxide-mediated polymerizations containing both metal-ion coordination and hydrogen-bonding sites.

The synthesis of a new difunctional nitroxide initiator combining two orthogonal supramolecular entities is reported; controlled radical polymerization of styrene using this initiator is demonstrated to generate well-defined heterotelechelic polymers in a one-step procedure.

Click chemistry beyond metal-catalyzed cycloaddition.

The overwhelming success of click chemistry encouraged researchers to develop alternative "spring-loaded" chemical reactions for use in different fields of chemistry. Initially, the copper(I)-catalyzed azide-alkyne cycloaddition was the only click reaction. In recent years, metal-free [3+2] cycloaddition reactions, Diels-Alder reactions, and thiol-alkene radical addition reactions have come to the fore as click reactions because of their simple synthetic procedures and high yields.

Ligand dynamics on the surface of zirconium oxo clusters.

The dynamics of carboxylate ligands on the surface of zirconium oxo clusters was investigated in two case studies. Zr4O2(methacrylate)12 was investigated by one- and two dimensional NMR spectra both in the solid state and in solution. In solution, the cluster is C2h symmetric; stepwise intramolecular exchange of the four non-equivalent ligands was observed when the temperature was raised from -80 degrees C to -50 degrees C.

One-step inkjet printing of conductive silver tracks on polymer substrates.

A one-step process to fabricate conductive features on flexible polymer substrates by inkjet printing an organometallic silver ink directly onto a substrate that is heated to 130 degrees C is presented. This process led to the immediate sintering of the printed features. The samples were left for 5 min at elevated temperature, which resulted in conductive silver features with a resistivity of eight times the bulk silver value.

'Clicking' on the nanoscale: 1,3-dipolar cycloaddition of terminal acetylenes on azide functionalized, nanometric surface templates with nanometer resolution.

Electro-oxidative lithography is used as a tool to create chemical nanostructures on an n-octadecyltrichlorosilane (OTS) monolayer self-assembled on silicon. The use of a bromine precursor molecule, which is exclusively assembled on these chemical templates, can be used to further functionalize the nanostructures by the site-selective generation of azide functions and performing the highly effective 1,3-dipolar cycloaddition reaction with acetylene functionalized molecules. The versatility of this reaction scheme provides the potential to integrate a large variety of functional molecules, to tailor the surface properties of the nanostructures or to anchor molecular building blocks or particles in confined, pre-defined surface areas.

Fast surface modification by microwave assisted click reactions on silicon substrates.

Microwave irradiation has been used for the chemical modification of functional monolayers on silicon surfaces. The thermal and chemical stability of these layers was tested under microwave irradiation to investigate the possibility to use this alternative heating process for the surface functionalization of self-assembled monolayers. The quality and morphology of the monolayers before and after microwave irradiation was analyzed by surface-sensitive techniques, such as Fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM), and contact angle measurements.

Exploring the functional interaction between POSH and ALIX and the relevance to HIV-1 release.

Background: The ALG2-interacting protein X (ALIX)/AIP1 is an adaptor protein with multiple functions in intracellular protein trafficking that plays a central role in the biogenesis of enveloped viruses. The ubiquitin E3-ligase POSH (plenty of SH3) augments HIV-1 egress by facilitating the transport of Gag to the cell membrane. Recently, it was reported, that POSH interacts with ALIX and thereby enhances ALIX mediated phenotypes in Drosophila.

Toward main chain metallo-terpyridyl supramolecular polymers: "the metal does the trick".

Metallo-supramolecular chemistry offers possibilities for the construction of stimuli-responsive polymeric materials where the environment can have a large impact on the reversibility and strength of interactions between the individual components. The potential of manipulating the strength of the intermolecular non-covalent bonds can result in impressive modifications of the metallo-supramolecular structure and, subsequently, produces changes in the properties of the designed material. The present feature article provides an overview on recent developments in the field of metallo-polymerization of chelating terpyridyl and analogues ligands.

Spectroscopic investigation of the ultrafast photoinduced dynamics in pi-conjugated terpyridines.

Ultrafast light-induced processes in a series of pi-conjugated mono-, bis-, tris- and tetrakis(terpyridine) derivatives are investigated by femtosecond time-resolved spectroscopy. Non-exponential excited-state dynamics involving singlet-triplet intersystem crossing are observed which span from picoseconds to nanoseconds (see figure). Time-resolved spectroscopy is applied to investigate the ultrafast relaxation dynamics of several pi-conjugated mono-, bis-, tris- and tetrakis(terpyridine) derivatives.

Synthesis, characterization, and electro-optical properties of Zn(II) complexes with pi-conjugated terpyridine ligands.

A series of nine zinc(II) complexes containing substituted 4'-phenyl-2,2':6',2''-terpyridines as ligands is synthesized and fully characterized. The ground-state structures of four examples are calculated by means of DFT and their structural features are confirmed by experimental Raman spectroscopy. Special focus is placed on the degree of pi-electron delocalization between the terpyridine unit and the attached phenyl moiety.

Screening the synthesis of 2-substituted-2-oxazolines.

2-Oxazolines are well-known organic compounds which are included in a variety of complex biologically active structures and play a role as catalyst ligands and intermediates for functional compounds. In addition, 2-oxazolines serve as monomers for the synthesis of substituted poly(imine)s by cationic ring-opening polymerization. For the latter application, the feasibility of preparing new 2-substituted-2-oxazolines was investigated using an automated synthesizer.

Characterization of different poly(2-ethyl-2-oxazoline)s via matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) coupled with CID (collision-induced dissociation) has been used for the detailed characterization of two poly(2-ethyl-2-oxazoline)s as part of a continuing study of synthetic polymers by MALDI-TOF MS/MS. These experiments provided information about the variety of fragmentation pathways for poly(oxazoline)s. It was possible to show that, in addition to the eliminations of small molecules, like ethene and hydrogen, the McLafferty rearrangement is also a possible fragmentation route.

Local probe oxidation of self-assembled monolayers: templates for the assembly of functional nanostructures.

The local oxidation of self-assembled monolayers with a scanning probe is a promising method for the generation of structures with chemical functionalities on the nanometer scale. This technique, which takes advantage of the chemical stability and versatility of self-assembled monolayers and the ability to pattern these monolayers by scanning-probe-based oxidation methods, enables the hierarchical assembly of complex structures in a controlled manner. Surface modification can be followed by the assembly of a further functional monolayer and/or additional surface-modification reactions in the targeted, sequential construction of functional device features.

Hydrodynamic properties of cyclodextrin molecules in dilute solutions.

Three well-known representatives of the cyclodextrin family were completely characterized by molecular hydrodynamics methods in three different solvents. For the first time the possibility of an estimation of velocity sedimentation coefficients s between 0.15 and 0.

2,2':6',2''-Terpyridine meets 2,6-bis(1H-1,2,3-triazol-4-yl)pyridine: tuning the electro-optical properties of ruthenium(II) complexes.

The synthesis of a series of heteroleptic ruthenium(ii)-complexes containing both, 2,2':6',2''-terpyridine and 2,6-bis(1H-1,2,3-triazol-4-yl)pyridine, is reported for the first time. The provided complexes feature photophysical and electrochemical properties in between those known for the respective homoleptic complexes. The flexibility with respect to lateral functional groups to be introduced into the complexes underlines the high potential for further functionalization steps.

Prospects of metal complexes peripherally substituted with sugars in biomedicinal applications.

Metal complexes possess unique tunable properties, such as radioactivity, cytotoxicity or photophysical features, enabling them to act as diagnostic tracers or therapeutic agents. In applying them in biological systems, it is often necessary to enhance their solubility and biocompatibility. To achieve such goals, like the targeting of binding domains, transport systems and enzyme activities, the attachment of carbohydrate moieties appears to be suitable.

Surface micellization of poly(2-oxazoline)s based copolymers containing a crystallizable block.

The micellization on surfaces of copoly(2-oxazoline) diblock copolymers consisting of a crystallizable poly(2-nonyl-2-oxazoline) (pNonOx) block linked to a poly(2-ethyl-2-oxazoline) (pEtOx) block is investigated. Those micelles are not pre-existing in the initial ethanol solution but are formed during the spin-coating process by the evaporation of the solvent inducing the precipitation of the less soluble pNonOx block. The morphology and size of the surface micelles vary according to the pNonOx molar fraction in the copolymers.

2-[1-(1-Naphth-yl)-1H-1,2,3-triazol-4-yl]pyridine.

In the crystal structure of the title compound, C(17)H(12)N(4), the angle between the naphthalene and 1H-1,2,3-triazole ring systems is 71.02 (4)° and that between the pyridine and triazole rings is 8.30 (9)°.

Multi-component hybrid organic-inorganic particles with highly dispersed silver nanoparticles in the external shell.

Complex hybrid organic-"multi inorganic" particles SiO2 PDCL-ZrO2 (Ag SiO2) (PDCL = poly(N-dicarbazolyl-lysine)) were synthesized stepwise from silica nanoparticles. First, the zirconia units were synthesized by sol-gel processing and anchored to the polyCOOH poly(dicarbazole-lysine) shell of pre-formed silica particles through metal coordination on residual COOH groups. Investigation of the particle morphology indicated a core-shell structure.

2-(1H-1,2,3-triazol-4-yl)-pyridine ligands as alternatives to 2,2'-bipyridines in ruthenium(II) complexes.

The synthesis of a variety of 2-(1H-1,2,3-triazol-4-yl)-pyridines by click chemistry is demonstrated to provide straightforward access to mono-functionalized ligands. The ring-opening polymerization of epsilon-caprolactone initiated by such a mono-functionalized ligand highlights the synthetic potential of this class of bidentate ligands with respect to polymer chemistry or the attachment onto surfaces and nanoparticles. The coordination to Ru(II) ions results in homoleptic and heteroleptic complexes with the resultant photophysical and electrochemical properties strongly dependent on the number of these ligands attached to the Ru(II) core.

Tuning the LCST of poly(2-oxazoline)s by varying composition and molecular weight: alternatives to poly(N-isopropylacrylamide)?

The cloud point of copolymers of 2-ethyl-2-oxazoline and 2-n-propyl-2-oxazoline could be tuned from 25 degrees C to 100 degrees C by varying molecular weight and composition; the reversibility and concentration dependence of the cloud points were evaluated to assess the potential of these copoly(2-oxazoline)s as alternatives to poly(N-isopropylacrylamide).

Reversible supramolecular functionalization of surfaces: terpyridine ligands as versatile building blocks for noncovalent architectures.

We report on the reversible and selective functionalization of surfaces by utilizing supramolecular building blocks. The reversible formation of terpyridine bis-complexes, based on a terpyridine ligand-functionalized monolayer, is used as a versatile supramolecular binding motif. Thereby, click chemistry was applied to covalently bind an acetylene functionalized Fe(II) bis-complex onto azide-terminated self-assembled monolayers.

Synthesis, microwave-assisted polymerization, and polymer properties of fluorinated 2-phenyl-2-oxazolines: a systematic study.

We present a detailed systematic study of the synthesis and ability of fluorinated 2-phenyl-2-oxazolines to undergo polymerization. The synthesis of these compounds is based on a two-step procedure that gives the desired 2-oxazolines in moderate-to-good yields. All the compounds were fully characterized by IR and NMR ((1)H, (13)C, and (19)F) spectroscopy, mass spectrometry, and elemental analysis.

Combination of different chemical surface reactions for the fabrication of chemically versatile building blocks onto silicon surfaces.

The use of nucleophilic displacement reactions on bromine-terminated monolayers is presented to create new functional moieties onto silicon surfaces. Functional amines were used as suitable nucleophiles to introduce versatile building blocks onto self-assembled monolayers to perform further surface chemistry toward the fabrication of surfaces with designed properties by combining compatible chemical routes. These modified substrates were analyzed by suitable surface sensitive techniques.

Controlled thermoreversible transfer of poly(oxazoline) micelles between an ionic liquid and water.

Poly(2-nonyl-2-oxazoline-block-2-ethyl-2-oxazoline) block copolymer micelles were investigated as an alternative system to the approach proposed by He and Lodge (Y. He and T. P.