Alkynylgold(I) C -Chiral Concave Complexes: Aggregation and Luminescence.

Chiral gold(I) acetylide trinuclear complexes 1-3 based on the cyclotribenzylene platform and terminal PR ligands (R=Ph, Et, and Cy, respectively), were characterized and their light emission studied. They exhibited long-lived blue phosphorescence in CHCl and a weak fluorescence in the UV. In MeOH/CHCl mixtures of >1:1 volume ratio, 1 and 2 exhibited a new emission band at ca.

Structural analyses of isolated cyclic tetrapeptides with varying amino acid residues.

Cyclic peptides represent a large class of substances that occur in nature with important biological and medical functions. Synthetic cyclic peptides are used as artificial receptors due to a series of advantages over conventional receptors. In order to optimize their binding abilities, investigations of their intrinsic structural properties especially with regard to the influence of different amino acid residues are fundamental.

Selective recognition of sulfate anions by a cyclopeptide-derived receptor in aqueous phosphate buffer.

A cyclopeptide-based anion receptor containing alternating 6-aminopicolinic acid and substituted (4R)-4-aminoproline subunits with appended β-alanine residues binds sulfate anions in water. Importantly, appreciable sulfate binding is even observed in phosphate buffer, hence in the presence of anions of similar structure but with a different degree of protonation. The cause for the high selectivity of this receptor is related to the mode of action of the sulfate-binding protein.

Structural analysis of an isolated cyclic tetrapeptide and its monohydrate by combined IR/UV spectroscopy.

Cyclopeptides are an important class of substances in nature, and their physiological effects are frequently based on the tendency to form bioactive conformations. Therefore the investigation of their structure yields an understanding of their functionalities. Mass-selective combined IR/UV spectroscopy in molecular beam experiments represents an ideal tool for structural analyses on isolated molecules in the gas phase, such as the investigated cyclo[L-Tyr(Me)-D-Pro](2) peptide and its complexes with water.