Substitutional disorder in a hypervalent diorganotin(IV) dihalide

Area of Science:

• Organometallic Chemistry
• Coordination Chemistry
• Crystallography

Background:

• Tin(IV) halides are important in various chemical applications.
• Understanding the coordination environment and solid-state structure of organotin compounds is crucial for predicting their properties.
• Substitutional disorder in metal halide complexes can significantly influence molecular and crystal packing.

Purpose of the Study:

• To elucidate the detailed crystal structure of bromidochloridobis[2-(dimethyl-amino-methyl)phenyl]tin(IV).
• To investigate the nature of halide disorder and its impact on the coordination geometry.
• To analyze the intermolecular interactions driving the supramolecular assembly in the solid state.

Main Methods:

• Single-crystal X-ray diffraction analysis was employed to determine the molecular and crystal structure.
• The structure was refined considering the substitutional disorder of bromide and chloride ligands.
• Analysis of bond distances, angles, and intermolecular contacts was performed.

Main Results:

• The crystal structure of [SnBr(0.65)Cl(1.35)(C(9)H(12)N)(2)] was determined, revealing a hexa-coordinated tin(IV) center.
• Significant substitutional disorder of bromide (0.65 occupancy) and chloride (1.35 occupancy) ligands was observed.
• A distorted octahedral geometry around the tin atom was confirmed, influenced by strong intramolecular N→Sn coordination.
• The molecules form a three-dimensional supramolecular network through intermolecular hydrogen bonding (H⋯X) and pi-stacking (H⋯benzene) interactions.

Conclusions:

• The compound exhibits a unique distorted octahedral coordination sphere due to intramolecular N→Sn bonding.
• Substitutional disorder of halide ligands is a key feature of this tin(IV) complex.
• Intermolecular interactions play a critical role in organizing the molecules into a stable three-dimensional supramolecular structure.