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Syntheses of Segmental Heteroleptic Ligands for the Self‐Assembly of Heteronuclear Helical Supramolecular Complexes
Author(s) -
Piguet Claude,
Bocquet Bernard,
Hopfgartner Gérard
Publication year - 1994
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19940770406
Subject(s) - chemistry , denticity , heteronuclear molecule , benzimidazole , supramolecular chemistry , combinatorial chemistry , catenane , stereochemistry , crystallography , crystal structure , organic chemistry , nuclear magnetic resonance spectroscopy , molecule
The development of a modified Phillips reaction allows the synthesis of complicated heteroleptic ligands based on pyridine and 1 H ‐benzimidazole moieties. The key‐step formation of aromatic 1 H ‐benzimidazole rings from N ‐(2‐nitroaryl)arenecarboxamides significantly improves the possibilities of the classical intermolecular Phillips reactions and can be applied to the synthesis of large oligo‐multidentate units. Segmental heteroleptic ligands containing two different bidentate coordinating units (see 14 ) or bidentate and terdentate sites connected by ‘diphenylmethane’ ( = methylenebis(phenylene)) spacers (see 15 and 16 ) were obtained in fair to good yield by using multistep syntheses following this strategy. Heterotrileptic ligands (bidentate‐terdentate‐bidentate, see 19 and 20 ; terdentate‐terdentate‐terdentate, see 23 ) requiring the simultaneous formation of four 1 H ‐benzimidazole rings in one step were prepared and demonstrate the extended possibilities of this methodology. Data are presented to show that the milder conditions used for this modified Phillips reaction together with its flexibility are essential for the development of ligands adapted for the self‐assembly of heteronuclear helical complexes.