Counterintuitive Lanthanide Hydrolysis-Induced Assembly Mechanism

Area of Science:

• Inorganic Chemistry
• Materials Science
• Analytical Chemistry

Background:

• Understanding lanthanide ion hydrolysis is crucial but limited by challenges in characterizing intermediate species.
• Existing technologies struggle with stable models for mass spectrometry under electrospray ionization (ESI) conditions.

Purpose of the Study:

• To stabilize hydrolyzed lanthanide ion clusters under ESI conditions.
• To develop a method for determining the nuclearity of these clusters.
• To elucidate the formation and evolution pathways of lanthanide hydroxide clusters.

Main Methods:

• Utilizing diketonate ligands to stabilize lanthanide ion clusters.
• Employing mass difference fingerprint of isomorphism (MDFI) for nuclearity determination.
• Single-crystal X-ray diffraction for structural analysis of the {Eu16} cluster.
• Photophysical measurements to assess cluster properties.

Main Results:

• Diketonate ligands successfully stabilized hydrolyzed lanthanide ion clusters for ESI mass spectrometry.
• The MDFI method accurately determined cluster nuclearity without depth resolution.
• Observed dominant hydrolysis pathways: {Eu3}-{Eu4}-{Eu9}-{Eu10}-{Eu11}-{Eu15}-{Eu16} and a minor path {Eu3}-{Eu4}-{Eu8-1}-{Eu8-2}.
• Crystal structure of {Eu16} revealed three octahedral {o-Ln6} units, challenging assumptions about subunit assembly.
• The {Eu} cluster exhibited a high solid-state emission quantum efficacy of 12.8%.

Conclusions:

• This study provides precise formulas and formation pathways for lanthanide hydroxide clusters.
• The findings offer fundamental insights into the assembly of small lanthanide hydroxide units.
• The developed methods are vital for the directional synthesis of lanthanide hydroxide clusters.