title: Electrolytic synthesis of aqueous aluminum nanoclusters and in situ characterization by femtosecond Raman spectroscopy and computations.
abstract: The selective synthesis and in situ characterization of aqueous Al-containing clusters is a long-standing challenge. We report a newly developed integrated platform that combines (i) a selective, atom-economical, step-economical, scalable synthesis of Al-containing nanoclusters in water via precision electrolysis with strict pH control and (ii) an improved femtosecond stimulated Raman spectroscopic method covering a broad spectral range of ca. 350-1,400 cm(-1) with high sensitivity, aided by ab initio computations, to elucidate Al aqueous cluster structures and formation mechanisms in real time. Using this platform, a unique view of flat [Al13(μ3-OH)6(μ2-OH)18(H2O)24](NO3)15 nanocluster formation is observed in water, in which three distinct reaction stages are identified. The initial stage involves the formation of an [Al7(μ3-OH)6(μ2-OH)6(H2O)12](9+) cluster core as an important intermediate toward the flat Al13 aqueous cluster.
authors.affiliation: Department of Chemistry, Oregon State University, Corvallis, OR 97331-4003.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Weimin
authors.initials: W
authors.lastname: Liu
authors.forename: I-Ya
authors.initials: IY
authors.lastname: Chang
authors.forename: Lindsay A
authors.initials: LA
authors.lastname: Wills
authors.forename: Lev N
authors.initials: LN
authors.lastname: Zakharov
authors.forename: Shannon W
authors.initials: SW
authors.lastname: Boettcher
authors.forename: Paul Ha-Yeon
authors.initials: PH
authors.lastname: Cheong
authors.forename: Chong
authors.initials: C
authors.lastname: Fang
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Keszler
mesh_terms: D017607:Aluminum Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D055664:Electrochemical Techniques / Q000379:methods*; D053758:Nanoparticles / Q000737:chemistry*; D013059:Spectrum Analysis, Raman; D014867:Water / Q000737:chemistry*
chemical_list: D017607:Aluminum Compounds; D014867:Water
keywords: Al aqueous speciation; computational chemistry; electrochemistry; reaction pathway; ultrafast Raman