An efficient route to pyridine and 2,2′-bipyridine macrocycles incorporating a triethylenetetraminetetraacetic acid core as ligand for lanthanide ions

Sequential Nitrile Amidination-Reduction as a Straightforward Procedure to Selective Linear Polyamine Preparation

A straightforward strategy toward the efficient synthesis of linear saturated polyamines containing 1,2-diaminoethane and/or 1,3-diaminopropane fragments has been developed. The procedure is based on the chemistry of 5- and 6-membered cyclic amidines, including their efficient synthesis from nitrile precursors and subsequent chemoselective reductive-opening by a borane-dimethyl sulfide complex. This two-step procedure provides a robust methodology for the synthesis of linear polyamine skeletons under nonharsh conditions and free of using selective protective groups or tedious workups.

Aromatic and heteroaromatic azacrown compounds: advantages and disadvantages of rigid macrocyclic ligands

Current approaches to the synthesis of aromatic and heteroaromatic azamacrocycles and their derivatives are summarized and systematized. The relationship between the structure of azacrown compounds and their complexation behaviour towards metal cations is analyzed. The diversity of practical applications of azamacrocyclic derivatives in medicine, biology and analytical and organic chemistry, as well as for the design of molecular devices is demonstrated.

The bibliography includes 307 references.

Stable Europium(III) Complexes with Short Linkers for Site-Specific Labeling of Biomolecules

In this study, two new terpyridine-based Eu^III complexes were synthesized, the structures of which were optimized for luminescence resonance energy-transfer (LRET) experiments. The complexes showed high quantum yields (32 %); a single long lifetime (1.25 ms), which was not influenced by coupling to protein; very high stability in the presence of chelators such as ethylenediamine-N,N,N',N'-tetraacetate and ethylene glycol-bis(2-aminoethylether)-N,N,N',N'-tetraacetic acid; and no interaction with cofactors such as adenosine triphosphate and guanosine triphosphate. A special feature is the short length of the linker between the Eu^III ion and the maleimide or hydrazide function, which allows for site-specific coupling of cysteine mutants or unnatural keto amino acids. As a consequence, the new complexes appear particularly suited for accurate distance measurements in biomolecules by LRET.

High yielding synthesis of 2,2'-bipyridine macrocycles, versatile intermediates in the synthesis of rotaxanes

We present an operationally simple approach to 2,2'-bipyridine macrocycles. Our method uses simple starting materials to produce these previously hard to access rotaxane precursors in remarkable yields (typically >65%) across a range of scales (0.1-5 mmol). All of the macrocycles reported are efficiently converted (>90%) to rotaxanes under AT-CuAAC conditions. With the requisite macrocycles finally available in sufficient quantities, we further demonstrate their long term utility through the first gram-scale synthesis of an AT-CuAAC [2]rotaxane and extend this powerful methodology to produce novel Sauvage-type molecular shuttles.