Tris-ACE-(6,6′-bipyridyl)-α-cyclodextrin: synthesis and chirality of the tripodal metal complexes

Tris-ACE-α-cyclodextrin tripods: chemistry and metal coordination behaviour

“…If a majority of mononuclear podandates were formed, two binuclear species were also obtained as Earlier we also reported Fe III and Ru III "hard" cation coordination with (25). 7 Only ligand (29) was investigated in coordination with Fe III and Ru III "hard" cations considering possible changes in the coordination pathway induced by the three bisbipyridyl tethers in the structure of (29). As expected, the titration and the ligand speciation curves (Fig.…”

“…Compounds 5, 11 7, 7 8, 7 9, 12a 10, 13 11, 12b 12, 14 13, 15 16, 16 17, 11 20, 17 21 17 and 22, 17 cyclodextrins 4 18 and 4A 18 and tripod 25 7 were prepared by known literature procedures.…”

“…6 Very recently we reported in a short communication the first example of an α-CyD tripod grafted with 6,6′-bipyridyl units anchored at the 6-position, which generates the formation of tripodal mononuclear and dinuclear metal-induced Λ-helicates in a high chirality with some transitional cations. 7 Herein we describe in detail the synthesis and characterization of a complete new class of C 3 -symmetrical α-CyD-based tripods, in which the upper rim of the CyD is grafted by ureido-or thioureido-(6,6′-bis-heterocyclic) tethers. Except the 2,2′-bipyridyl unit other chosen bis-heterocyclic systems were 2,2′-bipyrazine, 4,4′-bithiazole, 4,4′-bipyrimidine and 6,6″-[oxobis-(methylene)]-bis-2,2′-bipyridine as shown in Fig.…”

Synthesis of Single Isomeric Complexes with Dissymmetric Structures Using Macrocyclic Homooligomers

“…Marsura et al. reported three‐fold symmetric derivatives of α‐cyclodextrin with three bipyridyl arms to form triple‐stranded helical complexes [19–21] . They also reported a β‐cyclodextrin derivative with seven bpy groups introduced via a flexible linkage, but the discussion on the resulting isomers upon metal complexation was not made [22] .…”

Synthesis of Single Isomeric Complexes with Dissymmetric Structures Using Macrocyclic Homooligomers

“…[1,[14][15][16][17][18] It is worth noting that the total number of coordination valences of the organic ligands and metal ions is matched in most systems.M arsura et al reported three-fold symmetric derivatives of a-cyclodextrin with three bipyridyl arms to form triple-stranded helical complexes. [19][20][21] They also reported a b-cyclodextrin derivative with seven bpy groups introduced via af lexible linkage,b ut the discussion on the resulting isomers upon metal complexation was not made. [22] As shown by this example and other macrocyclic derivatives with multiple metal binding units, [23][24][25][26] it is af ormidable challenge to demonstrate the formation of as ingle product when the number of total valences in the ligands and metals is mismatched.…”