title: Dynamic Diglyme-Mediated Self-Assembly of Gold Nanoclusters.
abstract: We report the assembly of gold nanoclusters by the nonthiolate ligand diglyme into discrete and dynamic assemblies. To understand this surprising phenomenon, the assembly of Au20(SC2H4Ph)15-diglyme into Au20(SC2H4Ph)15-diglyme-Au20(SC2H4Ph)15 is explored in detail. The assembly is examined by high-angle annular dark field scanning transmission electron microscopy, size exclusion chromatography, mass spectrometry, IR spectroscopy, and calorimetry. We establish a dissociation constant for dimer to monomer conversion of 20.4 μM. Theoretical models validated by transient absorption spectroscopy predict a low-spin monomer and a high-spin dimer, with assembly enabled through weak diglyme oxygen-gold interactions. Close spatial coupling allows electron delocalization between the nanoparticle cores. The resulting assemblies thus possess optical and electronic properties that emerge as a result of assembly.
authors.affiliation: Department of Chemistry, Colorado State University , Fort Collins, Colorado 80523, United States.
authors.forename: W Scott
authors.initials: WS
authors.lastname: Compel
authors.affiliation: Department of Chemistry, Colorado State University , Fort Collins, Colorado 80523, United States.
authors.forename: O Andrea
authors.initials: OA
authors.lastname: Wong
authors.affiliation: Departments of Chemistry and Physics, Nanoscience Center, University of Jyväskylä , 40014 Jyväskylä, Finland.
authors.forename: Xi
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Chemistry and Biochemistry, Florida State University , Tallahassee, Florida 32306, United States.
authors.forename: Chongyue
authors.initials: C
authors.lastname: Yi
authors.affiliation: Department of Chemistry, Colorado State University , Fort Collins, Colorado 80523, United States.
authors.forename: Roy
authors.initials: R
authors.lastname: Geiss
authors.affiliation: Departments of Chemistry and Physics, Nanoscience Center, University of Jyväskylä , 40014 Jyväskylä, Finland.
authors.forename: Hannu
authors.initials: H
authors.lastname: Häkkinen
authors.affiliation: Department of Chemistry and Biochemistry, Florida State University , Tallahassee, Florida 32306, United States.
authors.forename: Kenneth L
authors.initials: KL
authors.lastname: Knappenberger
authors.affiliation: Department of Chemistry, Colorado State University , Fort Collins, Colorado 80523, United States.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Ackerson
keywords: diglyme; dynamic assembly; gold nanoclusters; transient absorption spectroscopy