Synthesis and Aggregation Properties of Polycationic Perylenetetracarboxylic Acid Diimides

Synthesis and Characterization of Bola-Amphiphilic Porphyrin-Perylenebisimide Architectures

We report on the synthesis and characterization of a family of three water-soluble bola-amphiphilic zinc-porphyrin-perylenebisimide triads containing oligo carboxylic-acid capped Newkome dendrons in the periphery. Variations of the perylenebisimide (PBI) core geometry and dendron size (G1 and G2 dendrons with 3- and 9-carboxylic acid groups respectively) allow for tuning the supramolecular aggregation behavior with respect to variation of the molecular architecture. The triads show good solubility in basic aqueous media and aggregation to supramolecular assemblies. Theoretical investigations at the DFT level of theory accompanied by electrochemical measurements unravel the geometric and electronic structure of the amphiphiles. UV/Vis and fluorescence titrations with varying amounts of THF demonstrate disaggregation.

Electronic Communication in Confined Space Coronas of Shell-by-Shell Structured Al2 O3 Nanoparticle Hybrids Containing Two Layers of Functional Organic Ligands

A first series of examples for confined space interactions of electron-rich and electron-poor molecules organized in an internal corona of shell-by-shell (SbS)-structured Al₂ O₃ nanoparticle (NP) hybrids is reported. The assembly concept of the corresponding hierarchical architectures relies on both covalent grafting of phosphonic acids on the NPs surface (SAMs formation; SAM=self-assembled monolayer) and exohedral interdigitation of orthogonal amphiphiles as the second ligand layer driven by solvophobic interactions. The electronic communication between the chromophores of different electron demand, such as pyrenes, perylenediimides (PDIs; with and without pyridinium bromide headgroups) and fullerenes was promoted at the layer interface. In this work, it is demonstrated that the efficient construction principle of the bilayer hybrids assembled around the electronically "innocent" Al₂ O₃ core is robust enough to achieve control over electronic communication between electron-donors and -acceptors in the interlayer region. The electronic interactions between the electron-accepting and electron-donating moieties approaching each other at the layer interface were monitored by fluorescence measurements.

Manufacturing Nanoparticles with Orthogonally Adjustable Dispersibility in Hydrocarbons, Fluorocarbons, and Water

We describe a universal wet‐chemical shell‐by‐shell coating procedure resulting in colloidal titanium dioxide (TiO₂) and iron oxide (Fe₃O₄) nanoparticles with dynamically and reversibly tunable surface energies. A strong covalent surface functionalization is accomplished by using long‐chained alkyl‐, triethylenglycol‐, and perfluoroalkylphosphonic acids, yielding highly stabilized core–shell nanoparticles with hydrophobic, hydrophilic, or superhydrophobic/fluorophilic surface characteristics. This covalent functionalization sequence is extended towards a second noncovalent attachment of tailor‐made nonionic amphiphilic molecules to the pristine coated core–shell nanoparticles via solvophobic (i.e. either hydrophobic, lipophobic, or fluorophobic) interactions. Thereby, orthogonal tuning of the surface energies of nanoparticles via noncovalent interactions is accomplished. As a result, this versatile bilayer coating process enables reversible control over the colloidal stability of the metal oxide nanoparticles in fluorocarbons, hydrocarbons, and water.

Influence of electronic and molecular structure on the fragmentation dynamic of even-electron carbocationic triangulenes and helicenes in the gas phase

Stable, long-lived organic cations are directly transferred by electrospray ionization (ESI) from solution into the gas phase where their collision-induced dissociations (CID) are studied by tandem mass spectrometry. Three related types of triphenyl carbenium ions are investigated, in which the meta positions are either substituted by methoxy groups or tertiary nitrogen bridges, including tetramethoxyphenylacridinium (TMPA⁺ ), dimethoxyquinacridinium (DMQA⁺ ), and triazatriangulenium (TATA⁺ ) cations. These ions are triangular in shape with increasing degrees of planarity. Fragmentation occurs at the periphery of the triangular molecule, involving the methoxy groups and the substituent of the nitrogen bridge. Each initial precursor cation is an even electron (EE) system and shows competing dissociations into both even (EE) and odd electron (OE) fragment ions. The latter reaction is a breach of the classic 'even-electron rule' in mass spectrometry. While the EE fragment dissociates similar to the precursor, the OE fragment ion shows a rich radical-induced fragmentation pattern. Two driving forces direct the fragmentation of the EE precursor ion toward OE fragment ions, including the release of stabilized radicals and the extension of the π-system by increasing planarization of the triangulene core. Copyright © 2017 John Wiley & Sons, Ltd.

Water-soluble perylenediimides: design concepts and biological applications

Water-soluble perylenediimides (PDIs) with high fluorescence intensity, photostability and biocompatibility have been successfully prepared and applied in the biological field.

Anionic polymerization by an electron transfer process from a CdSe quantum dot–perylenediimide (PDI) system

Reversible physical interactions between CdSe quantum dots (QDs) and perylenediimide (PDI) derivatives have been investigated.

Fused perylene-phthalocyanine macrocycles: a new family of NIR-dyes with pronounced basicity

The synthesis and characterization of a new type of chromophore, namely PePc consisting of a central phthalocyanine core and four fused perylene-bisimide (PBI) units is described for the first time. The entire architecture represents a highly extended conjugated heterocyclic π-system with C4h symmetry. In order to guarantee pronounced solubility in organic solvents the corresponding PBI units were bay-functionalized with tert-butylphenoxy substituents. Next to the metal-free macrocycle, PePcH2 , also metallated macrocycles PePcM (M=Zn, Ni, Pb, Ru, Fe) were synthesized. The extensive fusion of the corresponding aromatic building blocks to the very large extended π-system leads to a very narrow HOMO-LUMO gap and as a consequence to transparency in the visible but light absorption in the NIR region. Significantly, the azomethine N-atoms N1N4 of PePcM and PePcH2 are highly basic. The corresponding tetraprotonated systems can only be deprotonated with very strong non-nucleophilic bases such as phosphazene bases. In the protonated forms PePcMH4 (4+) and PePcMH6 (4+) the absorption maximum is shifted back to the visible region due to the loss of conjugation. The experimental findings were corroborated with quantum mechanical calculations.

Grafting perylenes to ZnO nanoparticles

A new prototype of dendritic perylenes suitable for the chemical functionalization of inorganic nanoparticles was synthesized and characterized. The bay-functionalized perylene core of these molecular architectures was coupled to a catechol moiety, which serves as an anchor group for the functionalization of metal oxides, in particular ZnO. To increase the solubility of both the perylene and the targeted hybrid nanostructures, a Newkome-type dendron bearing nine positive charges was introduced. This charge was also employed to stabilize the nanoparticles and further protect them from Ostwald ripening through Coulombic repulsion. ZnO quantum dots with an average diameter of 5 nm were synthesized and functionalized with the perylene derivative. Successful functionalization was clearly demonstrated by dynamic light scattering, zeta-potential measurements, thermogravimetric analysis/MS, and UV/Vis and fluorescence spectroscopy. The generated particle dispersions were stable against agglomeration for more than eight weeks.

Novel EDTA-ligands containing an integral perylene bisimide (PBI) core as an optical reporter unit

The synthesis, characterization and metal complexation of a new class of perylene bisimides (PBIs) as an integral part of ethylenediaminetetraacetic acid (EDTA) are reported.