Formation of nanoscale [Ge4O16Al48(OH)108(H2O)24]20+ from condensation of ε-GeAl128+ Keggin polycations.

Formation of nanoscale [Ge4O16Al48(OH)108(H2O)24]20+ from condensation of ε-GeAl128+ Keggin polycations.
Angew Chem Int Ed Engl. 2021 Jan 22;:
Authors: Shohel M, Bjorkjund JL, Smith JA, Kravchuk DV, Mason SE, Forbes T
Abstract
Keggin-type polyaluminum cations belong to a unique class of compound with their large positive charge, hydroxo bridges, and divergent isomerization/oligomerization. Previously reports indicate that oligomerization of this species can only occur through one isomer (δ), but herein we report the isolation of largest Keggin-type cluster that occurs through self-condensation of four ε-isomers ε-GeAl128+ to form [Ge4O16Al48(OH)108(H2O)24]20+ cluster (Ge4Al48). The cluster was crystallized and structurally characterized by single-crystal X-ray diffraction (SCXRD) and the elemental composition was confirmed by ICP-MS and SEM-EDS.  Additional dynamic light scattering experiments confirms the presence of the Ge4Al48 in thermally aged solutions. DFT calculations reveal that a single atom Ge substitution in tetrahedral site of ε-isomer is the key for the formation of Ge4Al48 because it activates deprotonation at key surface sites that control the self-condensation process.
PMID: 33482020 [PubMed - as supplied by publisher]

Source: Angewandte Chemie - January 22, 2021 Category: Chemistry Authors: Shohel M, Bjorkjund JL, Smith JA, Kravchuk DV, Mason SE, Forbes T Tags: Angew Chem Int Ed Engl Source Type: research