C-HCl^- hydrogen bonds in solution and in the solid-state: HgCl₂ complexes with cyclen-based cryptands

Area of Science:

• Supramolecular Chemistry
• Inorganic Chemistry
• Structural Chemistry

Background:

• Cyclen-based cryptands are macrocyclic ligands with potential applications in coordination chemistry.
• Mercury(II) chloride (HgCl2) is a common inorganic salt used in various chemical processes.
• Hydrogen bonds play a crucial role in molecular recognition and self-assembly.

Purpose of the Study:

• To investigate the formation and structural characteristics of C-HCl- hydrogen bonds.
• To explore the complexation of HgCl2 with novel cyclen-based cryptands.
• To provide structural evidence for these interactions in both solution and solid states.

Main Methods:

• Synthesis of cyclen-based cryptands (1) and (2) bridged by glycol units.
• Complexation reactions between cryptands and HgCl2.
• X-ray crystallography for solid-state structure determination.
• Solution-state spectroscopic techniques (e.g., NMR) to study C-HCl- interactions.

Main Results:

• Structural evidence for C-HCl- hydrogen bonds in HgCl2 complexes with cyclen-based cryptands.
• The X-ray structure of complex 2/HgCl2 revealed an acetonitrile molecule within the cryptand cavity.
• The presence of di- and triethylene glycol units influences the cryptand structure and HgCl2 binding.

Conclusions:

• Cyclen-based cryptands can effectively bind HgCl2 and facilitate the formation of C-HCl- hydrogen bonds.
• These findings contribute to understanding non-covalent interactions in complex molecular systems.
• The study highlights the versatility of cryptands in host-guest chemistry and structural analysis.