title: Ag44(SeR)30: A Hollow Cage Silver Cluster with Selenolate Protection.
abstract: Selenolate protected, stable and atomically precise, hollow silver cluster was synthesized using solid state as well as solution state routes. The optical absorption spectrum shows multiple and sharp features similar to the thiolated Ag44 cluster, Ag44(SR)30 whose experimental structure was reported recently. High-resolution electrospray ionization mass spectrometry (HRESI MS) shows well-defined molecular ion features with two, three, and four ions with isotopic resolution, due to Ag44(SePh)30. Additional characterization with diverse tools confirmed the composition. The closed-shell 18 electron superatom electronic structure, analogous to Ag44(SR)30 stabilizes the dodecahedral cage with a large HOMO-LUMO gap of 0.71 eV. The time-dependent density functional theory (TDDFT) prediction of the optical absorption spectrum, assuming the Ag44(SR)30 structure, matches the experimental data, confirming the structure.
authors.affiliation: DST Unit of Nanoscience (DST UNS) and Thematic Unit of Excellence (TUE), Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036, India.
authors.forename: Indranath
authors.initials: I
authors.lastname: Chakraborty
authors.affiliation: Department of Applied Chemistry, Faculty of Science, Tokyo University of Science , 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan.
authors.forename: Wataru
authors.initials: W
authors.lastname: Kurashige
authors.affiliation: Department of Applied Chemistry, Faculty of Science, Tokyo University of Science , 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan.
authors.forename: Keita
authors.initials: K
authors.lastname: Kanehira
authors.affiliation: Departments of Chemistry and Physics, Nanoscience Center, University of Jyväskylä , Box 35, FI-40014 Jyväskylä, Finland.
authors.forename: Lars
authors.initials: L
authors.lastname: Gell
authors.affiliation: Departments of Chemistry and Physics, Nanoscience Center, University of Jyväskylä , Box 35, FI-40014 Jyväskylä, Finland.
authors.forename: Hannu
authors.initials: H
authors.lastname: Häkkinen
authors.affiliation: Department of Applied Chemistry, Faculty of Science, Tokyo University of Science , 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Negishi
authors.affiliation: DST Unit of Nanoscience (DST UNS) and Thematic Unit of Excellence (TUE), Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036, India.
authors.forename: Thalappil
authors.initials: T
authors.lastname: Pradeep
keywords: ESI MS; MALDI MS; TDDFT; nanomolecules; selenolate; silver clusters; superatoms