Diastereoselective Self-Assembly of Double- and Triple-Stranded Helicates from a d-Isomannide Derivative

Abstract

Difunctionalization of D-isomannide yielded a bis(bipyridine) ligand bearing four stereogenic centers whose diastereoselective self-assembly to enantiomerically pure dinuclear helicates upon coordination to different metal ions was investigated by NMR and CD spectroscopic as well as ESI mass spectrometric methods.

Self‐Assembly of Dinuclear Double‐ and Triple‐Stranded Helicates from Bis(bipyridine) Ligands Derived from Tröger's Base Analogues

“…However, zinc(II) has been found to form mainly hexacoordinated metal complexes in an octahedral coordination geometry in solution when treated with chelating ligands like 1,10-phenanthrolines or 2,2Ј-bipyridines, although fourfold coordination in a tetrahedral fashion has also been observed by us when -isomannide is used as structure-defining element. [20] According to this, the use of Zn 2+ may -in general -result in both species, double-stranded helicates and triple-stranded helicates, due to its "chameleon" character. [21] Therefore, the self-assembly of the zinc(II) complexes and also the stereoselectivity of these processes should be quite sensitive to the preorganization of the bis(bipyridine) ligand's conformation to ensure the formation of dinuclear coordination compounds.…”

“…All chemicals were used as received from commercial sources. Methyl 2,2Ј-bipyridine-5-carboxylate [20] [15] (2) and 2,2Ј-bipyridine-5-carboxylic acid [20] (7) were prepared according to published procedures. Numbering of the 1 H and 13 C is shown in Figure 12.…”

Assessment of climate change impacts on the hydrology of the Peruvian Amazon–Andes basin

“…To this end, a bipyridine unit as a tunable ligand is coupled with a long‐chain alkyl group through an ester linkage. Synthetically, 2,2′‐bipyridine‐5‐carboxylic acid ( 1 )10 is easily converted into the ester 2 (Scheme ).…”

Versatile tools in the construction of substituted 2,2′-bipyridines—cross-coupling reactions with tin, zinc and boron compounds

“…[88][89][90][91] The required compound was a 2,2 0 -bipyridine carrying either a halide or an alkynyl substituent in the 5-position. Our first approach started from a published Stille coupling procedure to give 5-nitro-2,2 0 -bipyridine (43) from commercially available 2-chloro-5-nitropyridine (41) and 42, followed by reduction to the amine and Sandmeyer reaction to give the required 5-iodo-2,2 0 -bipyridine.…”