Diasteroselective multi-component assemblies from dynamic covalent imine condensation and metal-coordination chemistry: mechanism and narcissistic stereochemistry self-sorting

Abstract

Self-assembly of a modified tris(2-pyridylmethyl)amine TPMA ligand, zinc(II) or cobalt(II) ions, and amino acids have been used effectively as stereo dynamic optical probes for the determination of the enantiomeric excess of free amino acids either using Electronic or Vibrational Circular Dichroism (CD and VCD). Herein, we report the mechanistic and stereochemical study of the self-assembly process which reveals a complex equilibrium in solution where even small variations in the experimental conditions can profoundly affect the final products of the reaction. In particular, variation on the metal stoichiometry switch give rises to an entirely enantio narcissistic self-assembly of the structure.

Extending substrate sensing capabilities of zinc tris(2‐pyridylmethyl)amine‐based stereodynamic probe

“…[41][42][43][44][45] On a parallel track, in the recent years, we are assisting to a revival of interest in the well-known, and widely exploited in nature, imine condensation chemistry. 8,[52][53][54][55][56][57][58][59][60][61][62] In this study, we extend the sensing capabilities of our zinc TPMA-based stereodynamic probe, showing its efficiency towards chiral amines, acids, and β-amino acids. 46,47 However, the main reason of interest lies in the reversibility of the C═N bond formation, which is extremely useful in dynamic covalent chemistry (DCC) and in the synthesis of functional architectures, and it is particularly effective in the presence of transition metal complexes.…”

“…[48][49][50][51] In the recent years, we have reported several examples on the catalytic and recognition capabilities of tripodal ligands, especially focusing on the TPMA molecular sensing toward α-amino acids ( Figure 1). 8,[52][53][54][55][56][57][58][59][60][61][62] In this study, we extend the sensing capabilities of our zinc TPMA-based stereodynamic probe, showing its efficiency towards chiral amines, acids, and β-amino acids.…”

Mixed Multimetallic tris(2‐pyridylmethyl)amine Based Complexes: Synthesis and Chiroptical Properties

“…Recently, we have been working in the application of tris(2‐pyridylmethyl)amine ( TPMA ) [18] metal complexes both in catalysis [19–21] and supramolecular chemistry [22–25] . In particular, we exploited the sensor capabilities of a series of TPMA based molecular architectures in the determination of the enantiomeric excess of chiral molecules, using Circular Dichroism (CD), [26–31] Vibrational Circular Dichroism (VCD), [32] and Circular Polarised Luminescence (CPL) [30] . In a typical experiment, mixing a modified TPMA zinc complex with one equivalent of the desired amino acid and half equivalent of zinc perchlorate resulted in the almost exclusive formation of a crystalline solid, corresponding to the trinuclear architecture 3‐ZnZnZn (Scheme 1).…”

Supramolecular cages as differential sensors for dicarboxylate anions: guest length sensing using principal component analysis of ESI-MS and 1H-NMR raw data

“…[26][27][28] In particular, it is possible to employ complex systems characterized by multiple equilibria which can be perturbed by the presence of an analyte toward a particular product distribution. In this context, we have recently developed a new class of supramolecular structures, [29][30][31][32][33] in particular molecular cages, which have been synthesized using imine dynamic covalent chemistry (DCC). These cages are obtained by self-assembly of modied tris(-pyridylmethyl)amine (TPMA) complexes and different diamine linkers.…”