How Do We Design and Perfect Atom- and Energy-efficient Synthesis of Revolutionary New Forms of Matter with Tailored Properties? Progress on Grand Challenge New Horizons for Grand Challenge Remaining ChallengeRefreshed Grand Challenge? Does enough remain to be grand? Yes. But the underlying issues and questions could use a rework. Is it tractable on the decadal scale or longer? Yes. What parts of the Grand Challenge have been solved? a.Soft matter issues of durability and architecture seems outmoded in the grand scheme of today’s fundamental issues. b.Today the worlds of soft matter issues and hard matter issues have merged. c.There have been tremendous ideological advances for catalysis to the point where focus on problems and issues specific to the energy issues might be helpful. Has the focus/scope of the Grand Challenge evolved? a.The separation of soft matter and hard matter seems artificial in today’s world. b.The real issue here is revolutionary forms of matter and tailored properties…how can we really do that? c.The development of 2D materials that can be assembled into materials with genuinely novel properties can point to new directions within this challenge area with tremendous opportunity. Is a new statement of the Grand Challenge needed? a.The broad statement of the challenge remains valid, but this challenge could use some re-formulation in light of the progress made. Should the Grand Challenge be retired? No Submitted by: James Yardley Affiliation: Columbia University

Scientific Achievement We have assembled atomically precise solid-state compounds from tunable molecular cluster superatom building blocks. In these materials, the constituent clusters are able to interact electronically and the assemblies show collective physical properties such as activated electrical transport with activation energies of 100 to 150 meV and spontaneous magnetic ordering at low temperature. Significance and Impact Conventional binary solid-state compounds, A x B y, are infinite, crystalline arrays of atoms A and B. In this work, we describe analogous binary solids in which the ‘atomic’ building blocks are pseudo-spherical molecular clusters rather than simply atoms. We have shown that the molecular cluster superatoms can communicate electronically and magnetically in these artificial solids, akin to atoms in conventional solid-state compounds. Research Details  We describe a series of solid-state materials formed from binary assembly of atomically precise molecular clusters.  We have characterize their collective structural, electrical and magnetic properties. Nanoscale Atoms in Solid-State Chemistry Space filling molecular structure of (A) Co 6 Se 8 (PEt 3 ) 6  2C 60 showing the crystal packing looking down the ab plane and of (B) Ni 9 Te 6 (PEt 3 ) 8  C 60. Carbon, black; nickel, red; cobalt, blue; phosphorus, orange; tellurium, teal; selenium, green. The ethyl groups on the phosphines were removed to clarify the view. (C) Plot of the conductance (G) vs. 1/T for Co 6 Se 8 (PEt 3 ) 6  2C 60. The four probes conductance measurements were done on a single crystal (black) and a pressed pellet (red). The Arrhenius fits are shown as solid lines. (D) Magnetization (M) as a function of applied field (H) at 10 K and 2 K for Ni 9 Te 6 (PEt 3 ) 8  C 60. The inset shows the enlarged magnetic hysteresis at 2 K. A B CD Xavier Roy, Chul-Ho Lee, Andrew C. Crowther, Christine L. Schenck, Tiglet Besara, Roger A. Lalancette, Theo Siegrist, Peter W. Stephens, Louis E. Brus, Philip Kim, Michael L. Steigerwald and Colin Nuckolls. "Molecular Quantum Dots as Atoms in Solid-State Chemistry". Science 341, (2013). DOI: /science