title: From designer clusters to synthetic crystalline nanoassemblies.
abstract: Clusters have the potential to serve as building blocks of materials, enabling the tailoring of materials with novel electronic or magnetic properties. Historically, there has been a disconnect between magic clusters found in the gas phase and the synthetic assembly of cluster materials. We approach this challenge through a proposed protocol that combines gas-phase investigations to examine feasible units, theoretical investigations of energetic compositional diagrams and geometrical shapes to identify potential motifs, and synthetic chemical approaches to identify and characterize cluster assemblies in the solid state. Through this approach, we established As7(3-) as a potential stable species via gas-phase molecular beam experiments consistent with its known existence in molecular crystals with As to K ratios of 7:3. Our protocol also suggests another variant of this material. We report the synthesis of a cluster compound, As7K1.5(crypt222-K)1.5, composed of a lattice of As7 clusters stabilized by charge donation from cryptated K atoms and bound by sharing K atoms. The bond dimensions of this supercluster assembled material deduced by X-ray analysis are found to be in excellent agreement with the theoretical calculations. The new compound has a significantly larger band gap than the hitherto known solid. Thus, our approach allows the tuning of the electronic properties of solid cluster assemblies.
authors: Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA. awc@psu.edu
authors: A Welford
authors: AW
authors: Castleman
authors: Shiv N
authors: SN
authors: Khanna
authors: Ayusman
authors: A
authors: Sen
authors: Arthur C
authors: AC
authors: Reber
authors: Meichun
authors: M
authors: Qian
authors: Kevin M
authors: KM
authors: Davis
authors: Samuel J
authors: SJ
authors: Peppernick
authors: Angel
authors: A
authors: Ugrinov
authors: Mark D
authors: MD
authors: Merritt
mesh_terms: D001151:Arsenic / Q000737:chemistry*; D003198:Computer Simulation; D003460:Crystallization / Q000379:methods*; D007726:Krypton / Q000737:chemistry*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D044367:Phase Transition; D013499:Surface Properties
chemical_list: D046911:Macromolecular Substances; D007726:Krypton; D001151:Arsenic