Jeffrey R. Long
Professor of Chemistry
Department of Chemistry
jrlong@berkeley.edu
510.642.0860

Research Expertise and Interest

inorganic and solid state chemistry, synthesis of inorganic clusters and solids, controlling structure, tailoring physical properties, intermetal bridges, high-spin metal-cyanide clusters, magnetic bistability

Description

When a correlation between the chemical structure and a physical property of a material is postulated, measurements on compounds exhibiting a range of structural variations are required to establish its validity and, ultimately, to optimize performance for an application. Yet the controlled modification of inorganic structures remains, in many instances, an open challenge. Our research is directed toward developing general strategies for the synthesis of inorganic clusters and solids.

Recent mass spectrometric investigations have provided tantalizing glimpses of large new classes of metal-nonmetal clusters generated in the gas phase by laser ablation. Reactor systems intended to produce bulk quantities of ligand-stabilized analogues of these species are being tested. Characterization of the clusters resulting from this versatile synthetic technique should provide insight into the fundamental processes involved in the transport, nucleation and growth of binary solid materials.

A practical formalism for manipulating the degree of connectivity in simple solid frameworks is being elaborated. Termed dimensional reduction, the method relates how a binary parent solid can be dismantled by incorporating additional anions that serve to terminate intermetal bridges. A database of binary and ternary metal-halide and metal-chalcogenide structures is currently being analyzed to evaluate the scope and limitations of this formalism. Its utility will then be tested by applying dimensional reduction in the synthesis and characterization of new solid materials.

Magnetic bistability has now been observed in several high-spin clusters, raising the possibility of storing data at an extremely high density by localizing each bit of information in a single molecule. However, to improve the durability of data storage, clusters with a substantially higher demagnetization energy barrier (S2|D|) must be synthesized. The relative simplicity of the structures and exchange pathways in metal-cyanide cluster systems should make them much more amenable to the design of such single-molecule magnets than previously studied metal-oxo systems. Directed assembly routes to constructing high-spin metal-cyanide clusters are under investigation.

The demand for new porous materials that function as molecular sieves and catalysts has prompted interest in crystal engineering, a solution-based route to solid synthesis. The problems of interpenetrating frameworks and architectural frailty often encountered with this method can be avoided by using isotropically expanded structural components. For example, replacing the Fe2+ ions in Prussian blue with larger [Re6Q8]2+ (Q = Se, Te) cluster cores more than doubles the volume of the framework cavities. Characterization of these and related porous materials is ongoing.

In Research News

Jeffery Long
January 10, 2017

Jeffrey Long reported devising a new material that can capture and release CO2 at a lower temperature and in a much greater volume than present-day technologies.

March 11, 2015

Capturing carbon from power plants is likely in the future to avoid the worst effects of climate change, but current technologies are very expensive. A new material, a diamine-appended metal-organic framework, captures and releases CO2 with much reduced energy costs compared to today’s technologies, potentially lowering the cost of capturing this greenhouse gas.

March 29, 2012

A new type of hybrid material developed at UC Berkeley could help oil and chemical companies save energy and money by eliminating an energy-intensive gas-separation process.

February 9, 2012

UC Berkeley chemists Chris Chang, Jeff Long and Marcin Majda have redesigned catalysts in ways that could have a profound impact on the chemical industry as well as on the growing market for hydrogen fuel cell vehicles.

January 26, 2012

Lawrence Berkeley National Laboratory is aiming to solve how to store enough of hydrogen-powered fuel cells, in a safe and cost-effective manner, to power a vehicle for 300 miles by synthesizing novel materials with high hydrogen adsorption capacities.

July 1, 2010

Researchers at Berkeley and other universities to find ways to capture carbon dioxide, produced by burning coal and natural gas, from the waste stream of power plants so that it can be sequestered underground.

May 3, 2010

The U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) has been awarded $8.6 million in Recovery Act funding for what the DOE calls "ambitious research projects that could fundamentally change the way the country uses and produces energy."

April 28, 2009

Two UC Berkeley faculty members will receive $30 million over the next five years from the U.S. Department of Energy to find better ways to separate carbon dioxide from power plant and natural gas well emissions and stick it permanently underground.



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