Keplerate cluster (Mo-132) mediated electrostatic assembly of nanoparticles

Jonathan Gooch; Abhishek A Jalan; Stephanie Jones; Corey R Hine; Rabeka Alam; Somenath Garai; Mathew M Maye; Achim Müller; Jon Zubieta

doi:10.1016/j.jcis.2014.06.059

Keplerate cluster (Mo-132) mediated electrostatic assembly of nanoparticles

J Colloid Interface Sci. 2014 Oct 15:432:144-50. doi: 10.1016/j.jcis.2014.06.059. Epub 2014 Jul 9.

Authors

Jonathan Gooch¹, Abhishek A Jalan¹, Stephanie Jones¹, Corey R Hine¹, Rabeka Alam¹, Somenath Garai², Mathew M Maye³, Achim Müller², Jon Zubieta⁴

Affiliations

¹ Department of Chemistry, Syracuse University, Syracuse, NY 13244, United States.
² Fakultät für Chemie der Universität, Postfach 100131, D-33501 Bielefeld, Germany.
³ Department of Chemistry, Syracuse University, Syracuse, NY 13244, United States. Electronic address: mmmaye@syr.edu.
⁴ Department of Chemistry, Syracuse University, Syracuse, NY 13244, United States. Electronic address: jazubiet@syr.edu.

PMID: 25086388
DOI: 10.1016/j.jcis.2014.06.059

Abstract

The electrostatic assembly between a series of differently charged Mo-132-type Keplerates present in the compounds (NH4)42[{(Mo(VI))Mo(VI)5O21(H2O)6}12 {Mo(V)2O4(CH3COO)}30].ca. {300 H2O+10 CH3COONH4} (Mo-132a), (NH4)72-n[{(H2O)81-n+(NH4)n} {(Mo(VI))Mo(VI)5O21(H2O)6}12 {Mo(V)2O4(SO4)}30].ca. 200 H2O (Mo-132b), and Na10(NH4)62[{(Mo(VI))Mo(VI)5O21(H2O)6}12 {Mo(V)2O4(HPO4)}30]. ca. {300H2O+2Na(+)+2NH4(+)+4H2PO4(-)} (Mo-132c) with cationic gold nanoparticles (AuNPs) was investigated for the first time. The rapid electrostatic assembly from nanoscopic entities to micron scale aggregates was observed upon precipitation, which closely matched the point of aggregate electroneutrality. Successful assembly was demonstrated using UV-vis, DLS, TEM, and zeta-potential analysis. Results indicate that the point at which precipitation occurs is related to charge balance or electroneutrality, and that counterions at both the Mo-132 and AuNP play a significant role in assembly.

Keywords: Au nanoparticles; Electrostatic assembly; Keplerate clusters; Micron scale aggregation; Zeta-potential analysis.