Diastereoselective Self‐Assembly of a Neutral Dinuclear Double‐Stranded Zinc(II) Helicate via Narcissistic Self‐Sorting

Abstract

An ew bis(salicylimine)l igand based on the Trç-ger's base scaffold was synthesized in racemic and enantiomerically pure form. Upon coordinationt oz inc(II) ions this ligand undergoes highly diastereoselective self-assembly into neutral dinuclear double-stranded helicates as proven by XRD analysisa nd via comparison of experimental ECD spectra with those simulated with quantum-chemicalm ethods. When the racemic ligand was used, self-assembly occurs under narcissistic self-sorting resulting in the formation of ar acemic pair of helicates as revealed by NMR spectroscopya nd XRD analysis.

Innovative Multipodal Ligands Derived from Tröger's Bases for the Sensitization of Lanthanide(III) Luminescence

“…It shouldb en oted, however,t hat the structures proposed for the Tb III coordination compounds for which the number of coordinated solventm olecules (q)v alues could not be determined experimentally are hypothetical and are only suggested upon considering similarcomplexes. [34,[49][50][51][52][53][54][55][56][57] This hypothesis allowed us to rationalize the unusual sigmoidal profile observed in the titrations of 4a and 4b as ar esponse to ac ooperative coordination process in which the formationo f1 :2 complexes favors the access of an ew lanthanide(III) ion, as observed for comparable systems such as the Eu III complex formed by ap hosphine ligand recently described by Cottere tal. [68][69][70] The ligand 4a forms a1:1 complex with Tb III ,e ven though it has a para-substitution pattern.…”

“…A 2:4 system could thus be constructed from the octahedron generated by two rhombs intertwined around the axis that includes the Tb III ions, with each rhomb formed of two ligand molecules and two Ln III (Figure 5). These rhomboidal structures, in which two vertices are formed by TB bridges and the other two by lanthanide(III) ions, have the same structures as the self‐assembly compounds formed between TBs and other transition‐metal ions [34, 49–57] . Even though the general stoichiometry of these coordination compounds is 2:2, Lützen and co‐workers proposed structures with two transition‐metal ions and three TB ligands, showing that a 2:4 structure could also be obtained from a steric point of view [49, 50] .…”

“…By analogy, we suggest that the actual coordination compounds obtained with 1:1 Tb III /ligand ratios ( 3 b , c and 4 a – c ) are in fact 2:2 systems formed by rhomboidal structures with two terbium(III) ions located in two vertices and the diazocinic cores of the two TB ligands in the remaining ones (Figure 6). It should be noted, however, that the structures proposed for the Tb III coordination compounds for which the number of coordinated solvent molecules ( q ) values could not be determined experimentally are hypothetical and are only suggested upon considering similar complexes [34, 49–57] …”

Efficient resolution of racemic crown-shaped cyclotriveratrylene derivatives and isolation and characterization of the intermediate saddle isomer

“…Due to our interest in dissymmetric [29–36] and concave molecular building blocks [37] and their implementation in supramolecular architectures like (allosteric) receptors [38–44] or metallosupramolecular helicates and cages [45–57] we were intrigued by the class of chiral CTVs. This is especially true for derivative 1 (Scheme 2) due to its interesting trifold substitution pattern with an almost orthogonal orientation of the functional groups which make it an ideal precursor for the synthesis of other elaborated derivatives [58–59] and the ease of a recently established large-scale synthesis reported by Rousseau and co-workers [60].…”

A Six‐Armed Phenhomazine Ligand with a Potential “Turn‐Off” Copper(II) Sensing Capability through Terbium(III) Luminescence Quenching

“…Nevertheless, a 2:2 Tb III – 1 complex is also feasible, with each Tb III ion coordinated by two acetate arms from each ligand 1 (Figure ). For example, 2:2 metallosupramolecular self‐assembled structures have been ubiquitously found by Lützen's group for complexes formed by TBs and transition metal ions, in which the V‐shaped structure of the TB scaffold favors a rhombic system with two ligands and two ions at the respective vertices . In the case of lanthanide(III) ions, 2:2 metallosupramolecular entities are known and in some cases were also found as key stable intermediates in the formation of more complex structures …”