Formation and Surface Behavior of Pt and Pd Complexes with Ligand Systems Derived from Nitrile-functionalized Ionic Liquids Studied by XPS

We studied the formation and surface behavior of Pt(II) and Pd(II) complexes with ligand systems derived from two nitrile-functionalized ionic liquids (ILs) in solution using angle-resolved X-ray photoelectron spectroscopy (ARXPS). These ligand systems enabled a high solubility of the metal complexes in IL solution. The complexes were prepared by simple ligand substitution under vacuum conditions in defined excess of the coordinating ILs, [C₃CNC₁Im][Tf₂N] and [C₁CNC₁Pip][Tf₂N], to immediately yield solutions of the final products. The ILs differ in the cationic head group and the chain length of the functionalized substituent. Our XPS measurements on the neat ILs gave insights in the electronic properties of the coordinating substituents revealing differences in donation capability and stability of the complexes. Investigations on the composition of the outermost surface layers using ARXPS revealed no surface affinity of the nitrile-functionalized chains in the neat ILs. Solutions of the formed complexes in the nitrile ILs showed homogeneous distribution of the solute at the surface with the heterocyclic moieties preferentially orientated towards the vacuum, while the metal centers are rather located further away from the IL/vacuum interface.     

Artificial Cytoskeleton Assembly for Synthetic Cell Motility

Imitation of cellular processes in cell-like compartments is a current research focus in synthetic biology. Here, a method is introduced for assembling an artificial cytoskeleton in a synthetic cell model system based on a poly(N-isopropyl acrylamide) (PNIPAM) composite material. Toward this end, a PNIPAM-based composite material inside water-in-oil droplets that are stabilized with PNIPAM-functionalized and commercial fluorosurfactants is introduced. The temperature-mediated contraction/release behavior of the PNIPAM-based cytoskeleton is investigated. The reversibility of the PNIPAM transition is further examined in bulk and in droplets and it could be shown that hydrogel induced deformation could be used to controllably manipulate droplet-based synthetic cell motility upon temperature changes. It is envisioned that a combination of the presented artificial cytoskeleton with naturally occurring components might expand the bandwidth of the bottom-up synthetic biology.     

Evolution of the “knitting pattern” morphology in ABC triblock copolymers

A new morphology of ternary ABC triblock copolymers is presented which results from the asymmetric interaction between a centre block (poly(ethylene-co-butene)) to different end blocks (polystyrene and poly(methyl methacrylate)). This morphology with the appearance of a “knitting pattern” can be described as an intermediate of a morphology of A, B and C lamellae and a morphology of A and C lamellae with B cylinders at the A/C interface.     

Small angle neutron scattering in Al?Cu?Mg alloys

The structure changes proceeding in AlCu 2.1 at.% Mg(x) alloys with magnesium concentration form 0 to 1.2 at.% at room temperature and 100 °C are followed by small-angle neutron investigation. The results are fitted on different models. The most important result is that with increase of the Mg contents clearly a growth of the thickness opposite to the growth of the growth of the diameter to discern. The results give a good idea of the formation of GPZI(Mg) with the adequate portion of magnesium in the AlCuMg(x)-alloys and their transition to GPZII(Mg) respectively θ″ (Mg).     

Liposome delivered and polymeric metal complexes as potential sensitizers for the photodynamic therapy of cancer

Different possibilities of macromolecular metal complexes as photosensitizers (PS) for their potential use in the photodynamic therapy of cancer are described. The prepared metal porphyrazin derivatives (metals: Zn(II), Si(IV)(X)₂) exhibit long wavelength absorption and high singlet oxygen quantum yields under irradiation. One possibility is the incorporation of the PSs in liposomal vesicles giving hydrophobic conjugates with low densitiy proteins in the serum after injection. Good tumor accumulation and photodynamic activities are observed. Increased tumor uptake is also known for Pcs covalently connected via the ligand to poly(ethylene glycol monomethyl ether). New compounds contain the hydrophilic polymer at axial substituents of Si(X)₂Pc and Si(X)₂Nc. Some newly synthesized compounds with only one functional group exhibit the possibility of coupling to macromolecules like e.g. monoclonal antibodies.