Heterochiral or Homochiral Self‐Assembly: Mercury(II), Cadmium(II), and Spontaneous Resolution of Silver(I) Complexes Derived from a Racemic Bis(pyridyl) Ligand

Abstract

A novel racemic bis(pyridyl) ligand (rac‐L) was designed and synthesized by Schiff condensation reaction. Five complexes, [Hg2(LR)(LS)Cl4]·2CH3CH2OH (1), [Cd(LR)(LS)Cl2]n (2), {[Cd(LR)(LS)SO4(H2O)]·11H2O}n (3), {[Ag(LR)2]NO3·CH3CN}n (4a) and {[Ag(LS)2]NO3·CH3CN}n (4b) have been synthesized and characterized. The different geometric features of complexes 1–4 were determined by single‐crystal X‐ray diffraction. The crystal structures show that the self‐assembly with racemic ligands can lead to homochiral or heterochiral complexes, through self‐recognition or self‐discrimination of the ligand units. Complex 1 exists as a 26‐membered binuclear heterochiral macrocycle. Complexes 2 and 3 form 1D mesomeric looped chain coordination polymers with different heterochiral self‐assembly types. More interestingly, two novel 2D homochiral coordination polymers 4a and 4b were obtained as racemic conglomerates via spontaneous resolution. Furthermore, the thermal stabilities and luminescence properties of complexes 1–4 were investigated.

Coordination-Driven Self-Assembly of Complexes Constructed from Two Helical Ligands: Synthesis, Structures, and Selective Gas Adsorption Properties

“…Chirality is considered a fundamental feature in natural processes and plays an integral role in many chemical and biological processes. − Currently, chiral metal complexes are widely used in asymmetric synthesis and catalysis, , enantiomeric separation, and supramolecular chemistry due to their ability to create asymmetric environments. − They are also widely used in chiral liquid crystals, chiral luminescent materials, − enantioselective sensors, , magnetic chiral compounds, and chiral reagents. , Typically, enantiomerically pure chiral ligands are used to construct chiral metal complexes. , However, metal complexes prepared from racemic ligands create more complex situations in which the possibility of chiral self-discrimination (heterochiral aggregation) and chiral self-recognition (homochiral aggregation) is feasible. Therefore, their self-assembly can be significantly different with racemic ligands having the potential to form novel and interesting molecular materials. − Helicity is one important origin of chirality.…”

Two-Dimensional Metal-Organic Framework Materials: Synthesis, Structures, Properties and Applications

“…The introduction of a free amine group demonstrated its ability to undergo intramolecular hydrogen bonding with bound anionic species due to which these are unapproachable to guest molecules. Apart from the aforesaid rhombic grid based 2D MOFs, several other examples are also reported. ,,,− …”