Molecular Polyarsenides of the Rare-Earth Elements

Area of Science:

• Organometallic Chemistry
• Inorganic Chemistry
• Rare-Earth Chemistry

Background:

• Polyarsenides are fascinating inorganic compounds with diverse structures.
• Rare-earth metals offer unique electronic properties for complex formation.

Purpose of the Study:

• To synthesize and characterize novel polyarsenide compounds involving rare-earth metals.
• To explore the structural and bonding characteristics of these new materials.

Main Methods:

• Chemical reduction of [Cp*Fe(η(5)-As5)] using [Cp''2Sm(thf)].
• X-ray crystallography for structural determination.
• Density Functional Theory (DFT) calculations for electronic structure analysis.

Main Results:

• Synthesis of two new rare-earth polyarsenides: [(Cp''2Sm)(μ,η(4):η(4)-As4)(Cp*Fe)] and [(Cp''2Sm)2As7(Cp*Fe)].
• Discovery of the first d/f-triple decker sandwich complex with an inorganic planar deck.
• Identification of an As4(2-) unit isolobal to cyclobutadiene and an As7(3-) cage with a norbornadiene-like structure.
• DFT calculations confirmed structural assignments and provided insights into As-As bonding.

Conclusions:

• This work presents the first examples of rare-earth metal polyarsenides.
• The novel d/f-triple decker complex represents a new class of sandwich compounds.
• The studied polyarsenide structures offer insights into bonding in inorganic ring and cage systems.