Bromination and iodination of diphosphane dichalcogenides

Area of Science:

• Inorganic Chemistry
• Organophosphorus Chemistry
• Coordination Chemistry

Background:

• Diphosphane dichalcogenides are compounds containing phosphorus and chalcogen elements.
• Their reactivity with halogens is not fully understood, particularly regarding structural outcomes.
• Previous studies have shown simple adduct formation with some related compounds.

Purpose of the Study:

• To synthesize and characterize novel adducts formed from the reaction of diphosphane dichalcogenides with bromine and iodine.
• To investigate the structural diversity and bonding in these new compounds using single crystal X-ray diffraction.
• To explore the influence of different diphosphane ligands and chalcogen atoms on the reaction products.

Main Methods:

• Synthesis of diphosphane dichalcogenides: dppmSe2, dppeSe2, diiprprpmSe2, diiprpeSe2, dppmS2, and dppeS2.
• Reaction of these compounds with elemental bromine (Br2) and iodine (I2) under various conditions.
• Characterization of the resulting products (1-15) using single crystal X-ray diffraction.

Main Results:

• Formation of simple adducts like dppe(SeBr2)2 and dppe(SeI2)2 with bromine and iodine, respectively.
• Observation of T-shaped geometry at selenium in bromine adducts and linear Se-I-I groups in iodine adducts.
• Isolation of complex products such as [dppmBr2]2+[Se2Br10]2- and [dppeBr2]2+·½[SeBr6]2-·[SeBr2·Br2·Br3]-.
• Discovery of a novel five-membered CP2Se2 heterocycle in the adduct [dppmSe2I]+[I3]-.
• Synthesis of analogous adducts with diisopropylphosphino ligands and disulfide compounds.

Conclusions:

• The reaction of diphosphane dichalcogenides with halogens yields a diverse range of adducts with unique structural features.
• The nature of the diphosphane ligand and the halogen influences the geometry and complexity of the products.
• This study expands the known chemistry of diphosphane dichalcogenides and their halogen adducts, revealing novel structural motifs.