Ag44(SeR)30: A Hollow Cage Silver Cluster with Selenolate Protection

Indranath Chakraborty; Wataru Kurashige; Keita Kanehira; Lars Gell; Hannu Häkkinen; Yuichi Negishi; Thalappil Pradeep

doi:10.1021/jz401879c

Ag44(SeR)30: A Hollow Cage Silver Cluster with Selenolate Protection

J Phys Chem Lett. 2013 Oct 3;4(19):3351-5. doi: 10.1021/jz401879c. Epub 2013 Sep 24.

Authors

Indranath Chakraborty¹, Wataru Kurashige², Keita Kanehira², Lars Gell³, Hannu Häkkinen³, Yuichi Negishi², Thalappil Pradeep¹

Affiliations

¹ DST Unit of Nanoscience (DST UNS) and Thematic Unit of Excellence (TUE), Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036, India.
² Department of Applied Chemistry, Faculty of Science, Tokyo University of Science , 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan.
³ Departments of Chemistry and Physics, Nanoscience Center, University of Jyväskylä , Box 35, FI-40014 Jyväskylä, Finland.

PMID: 26706648
DOI: 10.1021/jz401879c

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.

Keywords: ESI MS; MALDI MS; TDDFT; nanomolecules; selenolate; silver clusters; superatoms.