Chalcogen bonding vs. weakly coordinating anions - a solid state study on halidoselenium cations in an oxoanionic...

Area of Science:

• Inorganic Chemistry
• Solid-State Chemistry
• Supramolecular Chemistry

Background:

• Limited understanding of the solid-state structures and bonding in selenium-containing ionic compounds.
• Exploration of novel cations and their stabilization within oxoanionic environments is an active research area.

Purpose of the Study:

• To determine the crystal structure of selenoyl chloride (SeOCl2) for the first time.
• To synthesize and characterize novel compounds featuring the [SeCl3]+ and [Se2I4]2+ cations.
• To investigate the supramolecular assembly and non-covalent interactions in these new compounds.

Main Methods:

• Single-crystal X-ray diffraction for structural determination.
• Synthesis of novel selenium-containing salts.
• Computational studies including Density Functional Theory (DFT), Molecular Electrostatic Potential (MEP), Quantum Theory of Atoms in Molecules (QTAIM), and Natural Bond Orbital (NBO) analyses.

Main Results:

• The crystal structure of SeOCl2 was elucidated.
• The [SeCl3]+ cation was stabilized as disulfate and chlorosulfate salts, and the [Se2I4]2+ dication was stabilized in a tetrasulfate salt.
• Remarkable macromolecular arrangements and packing motifs were observed in the solid state, governed by strong chalcogen bonding and weaker halogen bonding.

Conclusions:

• Coulombic forces are primary drivers in these ionic systems.
• Directionality and orbital contributions of σ- and π-hole interactions are crucial for fine-tuning supramolecular assemblies.
• This work provides new insights into the structural diversity and non-covalent interactions of selenium-based ionic compounds.