Hypervalent organoselenium compounds stabilized by intramolecular coordination: synthesis and crystal structures

Area of Science:

• Organometallic Chemistry
• Materials Science
• Crystallography

Background:

• Hypervalent selenium compounds are of interest due to their unique bonding and reactivity.
• Intramolecular interactions play a crucial role in stabilizing novel molecular architectures.

Purpose of the Study:

• To synthesize and characterize two novel hypervalent selenium(IV) compounds.
• To investigate the structural properties and intermolecular interactions of these new organoselenium molecules.

Main Methods:

• Synthesis of selenium(IV) compounds using 2-chloro-1-formyl-3-(hydroxymethylene)cyclohexene and disodium diselenide.
• Characterization by FT-IR spectroscopy, ESI-MS, and single-crystal X-ray diffraction.
• Analysis of molecular packing and intermolecular interactions (π-π stacking, C-H...π, C-H...Se,O, C-H...O).

Main Results:

• Two novel hypervalent selenium(IV) compounds, 6-phenyl-6,7-dihydro-5H-2,3-dioxa-2aλ⁴-selenacyclopenta[hi]indene (14) and 5-phenyl-5,6-dihydro-4H-benzo[c][1,2]oxaselenole-7-carbaldehyde (15), were successfully synthesized.
• Compound 14 exhibits whole-molecule disorder and is stabilized by π-π stacking and C-H...π interactions, along with bifurcated C-H...Se,O interactions.
• Compound 15 features longer C-Se bonds and is stabilized by C-H...O interactions forming centrosymmetric dimers; it lacks π-π or C-H...π interactions.

Conclusions:

• The synthesis provides new examples of hypervalent selenium(IV) compounds stabilized by intramolecular and intermolecular forces.
• Structural analysis reveals distinct packing motifs and interaction types influencing the solid-state structures of these organoselenium compounds.
• The study contributes to understanding the structure-property relationships in novel hypervalent selenium chemistry.