Abstract
This study develops the first heteropentametal extended metal atom chain (EMAC) in which a string of nickel cores is incorporated with a diruthenium unit to tune the molecular properties. Spectroscopic, crystallographic, and magnetic characterizations show the formation of a fully delocalized Ru 2 5+ unit. This [Ru 2 ]-containing EMAC exhibits single-molecule conductance four-fold superior to that of the pentanickel complex and results in features of negative differential resistance (NDR), which are unobserved in analogues of pentanickel and pentaruthenium EMACs. A plausible mechanism for the NDR behavior is proposed for this diruthenium-modulated EMAC. Strings attached: The first pentametal heteronuclear string, [Ni + -Ru 2 5+ -Ni 2+ -Ni 2+ ], is prepared and the electronic structure is assigned by magnetic properties, DFT simulation, UV/Vis, and XPS spectra. This molecule is four-fold more conductive than that of its pentanickel analogue and exhibits characteristics of negative differential resistance (NDR; see figure). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.