title: Overcoming the Crystallization Bottleneck: A Family of Gigantic Inorganic {Pdx }(L) (x=84, 72) Palladium Macrocycles Discovered using Solution Techniques.
abstract: The {Pd84 }(Ac) wheel, initially discovered serendipitously, is the only reported giant palladium macrocycle-a unique structure that spontaneously assembles from small building blocks. Analogues of this structure are elusive. A new modular route to {Pd84 }(Ac) is described, allowing incorporation of other ligands, and a new screening approach to cluster discovery. Structural assignments were made of new species from solution experiments, overcoming the need for crystallographic analysis. As a result, two new palladium macrocycles were discovered: a structural analogue of the existing {Pd84 }(Ac) wheel with glycolate ligands, {Pd84 }(Gly) , and the next in a magic number series for this cluster family-a new {Pd72 }(Prop) wheel decorated with propionate ligands. These findings confirm predictions of a magic number rule for the family of {Pdx } macrocycles. Furthermore, structures with variable fractions of functional ligands were obtained. Together these discoveries establish palladium clusters as a new class of tunable nanostructures. In facilitating the discovery of species that would not have been discovered by orthodox crystallization approaches, this work also demonstrates the value of solution-based screening and characterization in cluster chemistry, as a means to decouple cluster formation, discovery, and isolation.
authors.affiliation: WEST Chem, School of Chemistry, University of Glasgow, University Avenue, Glasgow, G12 8QQ, UK.
authors.forename: Lorna G
authors.identifier: 0000-0003-2686-335X
authors.initials: LG
authors.lastname: Christie
authors.affiliation: WEST Chem, School of Chemistry, University of Glasgow, University Avenue, Glasgow, G12 8QQ, UK.
authors.forename: Andrew J
authors.identifier: 0000-0002-2042-7373
authors.initials: AJ
authors.lastname: Surman
authors.affiliation: WEST Chem, School of Chemistry, University of Glasgow, University Avenue, Glasgow, G12 8QQ, UK.
authors.forename: Rachel A
authors.initials: RA
authors.lastname: Scullion
authors.affiliation: WEST Chem, School of Chemistry, University of Glasgow, University Avenue, Glasgow, G12 8QQ, UK.
authors.forename: Feng
authors.initials: F
authors.lastname: Xu
authors.affiliation: WEST Chem, School of Chemistry, University of Glasgow, University Avenue, Glasgow, G12 8QQ, UK.
authors.forename: De-Liang
authors.initials: DL
authors.lastname: Long
authors.affiliation: WEST Chem, School of Chemistry, University of Glasgow, University Avenue, Glasgow, G12 8QQ, UK. lee.cronin@glasgow.ac.uk.
authors.forename: Leroy
authors.identifier: 0000-0001-8035-5757
authors.initials: L
authors.lastname: Cronin
keywords: ion mobility; palladium; polyoxopalladates; self-assembly; size exclusion