Chiral Self-Sorting in Truxene-Based Metallacages

Abstract

Two chiral face-rotating metalla-assembled polyhedra were constructed upon self-assembling achiral components, i.e., a tritopic ligand based on a truxene core (10,15-dihydro-5H-diindeno[1,2-a;1′,2′-c]fluorene) and two different hydroxyquinonato–bridged diruthenium complexes. Both polyhedra were characterized in solution as well as in the solid state by X-ray crystallography. In both cases, the self-sorting process leading to only two homo-chiral enantiomers was governed by non-covalent interactions between both truxene units that faced each other.

Controlling Chiral Self-Sorting in Truxene-Based Self-Assembled Cages

“…Compounds 1b [56], 2b and LBu [53], as well as compounds 1a and 2a [62], and complexes Ru [63] and Rh [64] were synthesized using procedures described in the literature. All reagents were of commercial reagent grade and were used without further purification.…”

“…Upon self-assembling, the ligands lose their mirror symmetry, which results in several possible Inorganics 2022, 10, 103 2 of 11 stereoisomers, i.e., an enantiomers couple (CC/AA) and the meso form (AC). We showed recently that the hexabutyl truxene ligand LBu reacts with the hydroxynaphtoquinonato diruthenium complex Ru to afford, thanks to a chiral self-sorting process, only the CC/AA enantiomers couple [53]. We hypothesized this selectivity was due to the through space interactions occurring between the butyl chains located within the cavity, which self-organize in an alternated way to minimize the constraints.…”

Chiral Truxene‐Based Self‐Assembled Cages: Triple Interlocking and Supramolecular Chirogenesis

“…For instance, association of ligand A and complex Ru afforded only a couple of enantiomers upon chiral self‐sorting (Figure 1a). [19b] Their cavity is partially obstructed by six butyl chains (three from each facing truxene platforms), which prevented any guest molecules from accessing the cavity or even cages interlocking. Inspired by these results obtained from an achiral ligand, we defined two new objectives: i) to construct an empty chiral cavity capable of accommodating planar achiral guests and ii) as an extension, to generate interlocked chiral dimeric cages in a control manner.…”

Control and Transfer of Chirality Within Well-Defined Tripodal Supramolecular Cages

“…Aiming at providing a general view about recent progress in the preparation of chiral tripodal cages displaying chirality dynamics, this mini-review summarizes current knowledge on how the chiral information can propagate along such tridimensional architectures. Control of the chirality within tripodal cages upon chiral sorting (Henkelis et al, 2014 ; Schaly et al, 2016 ; Jedrzejewska and Szumna, 2017 ; Schulte et al, 2019 ; Séjourné et al, 2020 ), or guest binding (You et al, 2012 ; Bravin et al, 2019 ; Pavlovic et al, 2019 ) are beyond the scope of this work.…”