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The synthesis and characterization of new 1,4,7,10-Cligands with different heterocyclic spacers of various lengths (bi- and triphyridine) or an azacrown pendant and their mono- and dinuclear Zn(II), Cu(II), and Ni(II) complexes is presented. The Zn(II) complexes were observed to show higher hydrolytic activity under physiological conditions compared to other complexes of the same type.

Tattooing is a widespread process of puncturing pigments into skin, whereas the resulting concentration inside the skin remains unknown. Many tattoo colorants are organic pigments, such as azo pigments, manufactured for other uses. To remove tattoos from skin, laser pulses at very high intensities are applied to the skin to destroy the tattoo pigments. Recent investigations have shown that several azo compounds are cleaved by laser light leading to potentially toxic or carcinogenic compounds. To assess the risk of tattooing and laser treatment of tattoos, the concentration of the pigments and their decomposition products in the skin must be determined. Therefore, an extraction method was established to determine the concentration of tattoo pigments and decomposition products quantitatively. The extraction of two widely used azo compounds, Pigment Red 22 and Pigment Red 9, and their laser-induced decomposition products, 2-methyl-5-nitroaniline, 4-nitrotoluene, 2,5-dichloraniline, and 1,4-dichlorobenzene, was accomplished using recovery experiments and HPLC-DAD technology. Despite the poor solubility of the pigments, a nearly complete recovery from aqueous suspension (>92%) or lysed skin (> 94%) was achieved. The decomposition products were extracted from aqueous suspension or skin showing a recovery of up to 100%, except for the very volatile 1,4-DCB.

The spectroscopic properties of two asymmetric indolylmaleimide derivatives, 4-bromo-3-(1'H-indol-3'-yl)-maleimide and 4-methyl-3-(1'H-indol-3'-yl)maleimide, are investigated and the bromo derivative is crystallized and its x-ray structure is determined. DFT calculations indicated that HOMO-1 to LUMO excitation is mainly responsible for the charge transfer character and that this transition changes its character drastically when Zn-cyclen complexation occurs.

Arcyriarubin A and arcyriaflavin A, two strongly emissive and intensely colored natural products containing both two indoles and a maleimide unit, are investigated. The results revealed that there is no electronic transition in which a large electron density is transferred from one indole unit to the maleimide part.

A histidine-coordinating metal complex substituted with methoxypyrrole amino acids (MOPAS) as a peptide beta-sheet bonder shows high affinity for a H2N-His-Leu-Leu-Val-Phe-OMe pentapeptide in DMSO solution. Within the complex, a beta-sheet conformation is induced into the pentapeptide by weak intra-assembly interactions with the MOPAS units.

Research has been conducted on the electron-withdrawing carbonyl and carboxyl groups at the alkyne termini. The effect of these groups on the enediynes' reactivity has been investigated via the experimental and computational techniques.

Photoinduced electron transfer was examined in a phenothiazine-riboflavin dyad assembled by zinc-imide coordination in water at neutral pH. The formation of the donor-acceptor complex in water was investigated using potentiometric titrations and a binding constant of log K 5.9. The strong binding constant provided support for the large fluorescence deactivation observed in the interaction between the riboflavin emission and the phenothiazine zinc complex.

An easy method for the synthesis of acyclic and macrocyclic enediynes involves the reaction between bis-propargyl bromide enediyne and weakly basic nucleophiles to change the enediynes' metal ion coordination. Different 12- to 16-membered enediyne macrocycles are formed depending on the bis-nucleophile used. Thermal stability studies on the synthesized enediynes using differential scanning calorimetry suggest an irreversible exothermic reaction at high temperatures. Metal ion coordination regulates the chemical reactivity of the macrocyclic enediynes.

The synthesis and characterization of silicon-bridged macrocyclic compounds are presented. The scheme involves the reaction of carbo- and heterocyclic dianions with bis-electrophiles. Silicalix(4)arene was formed when p-tert-butylmethoxybenzene has been used as starting material. X-ray crystallographic studies of sicalix(4)arene conformers showed a partial cone conformation. Tests also indicate that the macrocycles extract metal ions with less affinity compared to crown ethers.

The synthesis of benzoannelated (2.2)paracyclophanes leads to a study of their electronic properties. The process involves the series alkenylation of vicinal di- and tetrabromoalkanes with subsequent cyclization and dehydrogenation of the resulting (E,Z,E)-trienes. Spectroscopic and cyclic voltammetric studies show that, while the cyclophanes' pi-subsystems are too far for stepwise reduction, they can interact well enough with one another. This makes the cyclophanes highly efficient acceptors of four to six electrons.

Research has been conducted on the acetal produced cyclic enediyne. The structure and synthesis of this compound have been investigated and the details are included.

Crystallographic analysis shows that the stability of the dynamic supramolecular structure is increased by entropic effect when additional binding sites are located on the original molecule. The increase in the dicarboxylic acid bond length beyond the threshold level helical supramolecular structures are formed.

A study was conducted to demonstrate that Bacillus anthracis and Bordetella pertussis which secrete the adenylyl cyclase (AC) toxins edema factor (EF) and CyaA also possess cytidylyl cyclase (CC) and uridylyl cyclase (UC) activity. The results provide insight into the high substrate specificity and cytidylyl and uridylyl cyclase activity exhibited by both EF and CyaA and likely contribution of both cyclic cytidine 3',5'-monophosphate (cCMP) and cyclic uridine 3',5'-monophosphate (cUMP) toward the toxin actions.

The structures resulting from the incorporation of the cyclic [C.sup.[alpha]]-tetrasubstituted [alpha]-amino acids into peptides are examined. The studies have shown that the all-S-backbone-configured peptides have formed right-handed [3.sub.10]-helices, while the all-R-configured peptides have formed left-handed [3.sub.10]-helices in the solid state and solution.

A freely accessible internet database that provides a wealth of additional material, covering experimental procedures, toxicity data, alternative reaction procedures and data about energy efficiency is described. The database known as Organisch-chemischen Praktikum (NOP) can be individually adapted to a specific course teaching material in universities.

The kinetic studies of the hydrolysis of bis(4-nitrophenyl)phosphate (BNPP) in aqueous solution at 25 degree Celsius in the pH range 7 to 9 are reported. The results provide insight into the effect of type and length of the spacer bridging the two metal complexes, the metal ions Cu(II), Ni(II), or Zn(II) and of mono- and dinuclear complexes on the hydrolytic efficiency.

The synthesis and structural characterization of tetrahydrofuran C[alpha]-tetrasubstituted amino acids from methionine is described. The reaction induces two consecutive [beta]-turns as part of a tripeptide of aliphatic [alpha]-amino acids.

The templated photochemical reactions in a homogeneous solution, which are initiated or mediated by light, are reviewed. The findings suggest that shielding of prochiral faces, topochemical reaction control, templating, and aggregate or inclusion complex formation are strategies responsible for enhancing and controlling reaction efficiency regio- or stereoselectivity.

The use of reversible coordination to unsaturated transition metal complexes as receptor binding sites in molecular recognition is discussed. It is concluded that coordinatively unsaturated transition metal complexes are well established as binding sites for synthetic receptors.

The synthesis and properties of luminescent benzo crown ether with a pendant copper imidodiacetic acid complexes, which coordinates with high affinity to histidine is reported. Crown ethers of suitable size are the perfect artificial host compounds for ammonium ion binding, but the rather low affinity in aqueous solution prevents their use at physiological conditions.

Crown ether amino acids (CEAAs) with a luminescent phthalic ester or phthalimide moiety have been prepared. The binding events of the crown ether groups are monitored independently by changes of their specific emission properties.

Two new artificial photolyase models that recognize pyrimidine dimers in protic and aprotic organic solvents as well as in water through a combination of charge and hydrogen-bonding interactions are presented. The reaction in water is significantly faster than in organic solvents.

The synthesis of cyclic 10-membered tetrahydoxy enediynes is described. By the use of additional hydroxy groups, the cyclic enediynes become water soluble and can be regulated in their activity by cyclic protecting groups.

Research has been conducted on functionalized bi- and terpyridines. The authors report the development of the general route for the synthesis of these compounds, and demonstrate that each step of the route allows diversification.

NADH models with Zn(II)-cyclen substituents for reversible flavin binding in water is synthesized to provide a chemical rational for such an obviously optimal relative disposition of the redox partners for efficient reaction. A strong dependence of the reaction rate on the spacer length is observed, which indicate that within the dynamic reversible assembly only the optimal relative disposition of the redox partners ensures an efficient redox reaction.

Intercomponent photoinduced energy transfer or electron transfer within the dynamic assembly, which yields to a statistical library of donor-acceptor systems, is reported. Assemblies obtained by coordination with Sc(III) ion having Ru(bpy)(sub 3)- based components and anthracene-substituted ligands showed efficient intramolecular energy transfer from the excited ruthenium complex to the lowest excited state of the anthracene-bound component.

The induction of two acetylenic units into the olefin-arene bond in diarylethenes yields chromophores. These diaryl enediynes, on exposure to sunlight or UV radiation, give a cis-trans mixture of diaryl enediyne chromophore that is indicated by an absorption band at 366 nm in the UV spectra. X-ray crystallography enables the characterization of these chromophores.

A pyrene-labeled Zn²+-cyclen complex for the staining of DNA in agarose gels is reported. The metal chelate coordinates reversibly to the DNA phosphate backbone, which induces the formation of pyrene excimers. The typical pyrene excimer emission is used for the detection of the DNA. Staining is limited to agarose gels and is less sensitive than ethidium bromide, but DNA amounts as low as 10 ng and short DNA strands (∼300 b.p.) are detectable. Gel extraction as a standard technique in molecular biology was successfully performed after staining with Zn²+-cyclen-pyrene. Cytotoxicity tests on HeLa and V-79 cells reveal that the zinc-cyclen pyrene probe is significant less toxic compared to ethidium bromide.