Atomically precise rhodium-indium carbonyl nanoclusters: synthesis, characterization, crystal structure and...

Area of Science:

• Inorganic Chemistry
• Materials Science
• Nanotechnology

Background:

• The study builds upon previous work synthesizing the icosahedral [Rh12E(CO)27]n- (E = Ge, Sn, Sb, Bi) cluster family.
• Investigating the reactivity of [Rh7(CO)16]3- with indium(III) chloride (InCl3) aims to expand this family of metal clusters.

Purpose of the Study:

• To synthesize and characterize new indium-centered rhodium carbonyl nanoclusters.
• To explore the structural, electronic, and electrochemical properties of the newly formed clusters.
• To expand the known family of icosahedral rhodium carbonyl clusters.

Main Methods:

• Reactions involving [Rh7(CO)16]3- and InCl3 were performed under varying conditions (CO atmosphere vs. inert atmosphere).
• Characterization techniques included Infrared (IR) spectroscopy, Electrospray Ionization Mass Spectrometry (ESI-MS), and single-crystal X-ray diffraction.
• Electrochemical analysis involved Scanning Electron Microscopy with Energy Dispersive Analysis (EDS), in situ infrared spectroelectrochemistry, and Cyclic Voltammetry (CV).

Main Results:

• Isolation and characterization of the In-centered icosahedral nanocluster [Rh12In(CO)28]3-, isoelectronic and isostructural with known congeners.
• Identification of two novel species: octahedral [Rh6(CO)15InCl3]2- and dimeric [{Rh6(CO)15InCl2}2]2-.
• The [Rh12In(CO)28]3- cluster exhibits multivalence, undergoing reversible oxidation and reduction, functioning as an 'electron sponge'.

Conclusions:

• The reaction of [Rh7(CO)16]3- with InCl3 yields a diverse range of rhodium-indium clusters, with selectivity tunable by reaction parameters.
• The newly synthesized [Rh12In(CO)28]3- nanocluster demonstrates electrochemical behavior analogous to the [Rh12E(CO)27]n- series.
• Density Functional Theory (DFT) calculations were employed to investigate geometric variations in response to charge changes within the metal framework.