PROFILE
Profile of Richard Eisenberg Nicholette Zeliadt Science Writer
If Richard Eisenberg hadn’t accidentally spilled the flask containing a red, corrosive liquid one day in 1963, he might not have become the accomplished inorganic chemist he is today. Back then, as an undergraduate at Columbia University in New York City, he set about synthesizing an organometallic vanadium compound (1). However, to do that, he first had to make vanadium tetrachloride, a highly reactive liquid that gives off fumes of hydrochloric acid when exposed to moisture. On that day in 1963, Eisenberg had succeeded in generating a precious amount of vanadium tetrachloride when he dropped the flask, spilling its contents all over the fume hood of the laboratory. As a result of that incident, Eisenberg decided to take a break from synthesis and began using X-ray crystallography to analyze the structures of molecules made by others. Although he did not realize it at the time, this fortuitous turn of events ultimately led him down a fruitful path of research and discovery. In the decades that followed, Eisenberg— a professor of chemistry at the University of Rochester and a recently elected member of the National Academy of Sciences (NAS)— proceeded to make significant contributions to our understanding of the structure–function relationships of inorganic and organometallic compounds. Along the way, he became interested in applying his skills and knowledge toward what he calls the greatest scientific and technological challenge of the 21st century that is not directly related to human health: developing renewable energy for sustainable development on a global scale. Projected increases in global energy needs “can be met satisfactorily by only one kind of alternative energy—the Sun,” Eisenberg wrote in a 2009 Science article (2). One approach to harvesting sunlight for renewable energy involves mimicking the ability of green plants and other photosynthetic organisms to store the energy of sunlight in chemical bonds—an approach known as artificial photosynthesis, which is based on the light-driven splitting of water into hydrogen and oxygen. In his Inaugural Article, Eisenberg describes a highly active and robust artificial photosynthetic system for converting the protons in water to hydrogen gas, an attractive fuel that can be
readily converted into electrical energy and produces no carbon dioxide on combustion, in contrast with all other fuels (3). Science in the City
A native New Yorker, Eisenberg grew up in the Bronx near Yankee Stadium, which helped to foster his long-standing love for the New York Yankees. His inquisitive young mind began to take an interest in science after he read about the planets and solar system in The Book of Knowledge. Eisenberg recalls taking a couple of chemistry classes while he was a student at Bayside High School in Queens, but says he did not become seriously interested in chemistry until he arrived at Columbia University in 1959, at the age of 16. During his first year at Columbia, Eisenberg says that he and his chemistry classmates “were just hanging on by our fingernails.” However, by his second year, he discovered that he enjoyed organic chemistry, in particular learning how to build and synthesize molecules and understanding their properties based on their functional groups. Subsequent coursework in physical chemistry gave him insight into the principles of how molecules hold together and how collections of molecules behave. “All of this sounded great,” Eisenberg says, “but what really sealed the deal for me in chemistry was when I met Harry Gray.” At the beginning of 1963, Eisenberg was finishing his senior year in college and had decided that he wanted to try his hand at research. One of Eisenberg’s classmates, John Alexander, was working in the laboratory of Harry Gray, who was then a young assistant professor of chemistry at Columbia, and urged Eisenberg to talk with Gray about working on a research project in Gray’s laboratory. Eisenberg had always been intimidated by faculty, but as soon as he stepped into Gray’s office, his fears subsided. “Harry looked up and said, ‘Rich, I’ve been waiting to see you, we’ve got some great stuff going,’” Eisenberg recalls. Back then, Gray’s laboratory was investigating the electronic structures of inorganic metal complexes to understand their vivid colors and magnetic properties. For his
18346–18348 | PNAS | November 12, 2013 | vol. 110 | no. 46
Richard Eisenberg. Image courtesy of Marcia Eisenberg.
senior research project, Eisenberg worked on synthesizing an organometallic vanadium complex, the precursor of which ended up spilled in the fume hood. He later decided to continue working in Gray’s laboratory while he pursued his PhD. “[Gray’s] enthusiasm and interest in science were really just contagious,” Eisenberg explains. “I liked the exploration of finding something new.” From Synthesis to Crystallography
For his graduate research, Eisenberg sought to determine the crystal structures of some of the brightly colored molecules synthesized in Gray’s laboratory. He went to Brookhaven National Laboratory in Upton, NY, to learn how to do X-ray crystallography from chemist James Ibers, who later moved to Northwestern University in Evanston, IL, in 1965. At that time, X-ray crystallography was less automated than it is today, and it took about 6 weeks for Eisenberg to collect his data. However, by the middle of his first year in graduate school, Eisenberg had determined the first crystal structure of a so-called metal dithiolene complex, forming the basis for his first publication (4). The metal dithiolene complex that Eisenberg studied was one of a class of molecules of great interest to Gray and other chemists This is a Profile of a recently elected member of the National Academy of Sciences to accompany the member’s Inaugural Article on page 16716 in issue 42 of volume 110.
www.pnas.org/cgi/doi/10.1073/pnas.1319293110
PROFILE
in the 1960s because of their unusual redox and magnetic properties and colors. A dithiolene is a group of connected atoms that acts as a ligand to bind to a metal ion through two sulfur atoms. Back then, many chemists thought that complexes containing three dithiolene ligands attached to the metal ion would adopt an octahedral molecular geometry, which at the time was the only known geometry for metal ions bound to six atoms. However, Eisenberg’s crystal structures revealed that complexes containing three dithiolene ligands adopt a trigonal prismatic geometry (5). In 1967, at the age of 24, Eisenberg completed his PhD and, with a grant from the National Science Foundation, continued his work on the structures of metal complexes as an assistant professor at Brown University in Providence, RI. Although he always maintained an interest in dithiolene complexes, he began studying the structures of metal nitrosyl complexes, which contain a metal atom bound to nitric oxide (NO). His crystal structures revealed the geometry of the metal–NO bond in several different metal complexes and illustrated how the metal– NO arrangement can shift between linear and bent geometries (6). A Shift in Approach
In 1974, Eisenberg accepted a position at the University of Rochester in Rochester, NY, to establish an inorganic chemistry program there. He directed his research efforts toward catalysis. He first studied the reduction of NO and then worked on a reaction known as the water gas shift reaction, which converts water and carbon monoxide to hydrogen gas and carbon dioxide—a reaction that had been used industrially as part of a process to make long chain hydrocarbons from coal (7, 8). His laboratory also studied reactions involving the addition of molecular hydrogen, H2, to metal complexes and organic molecules. Molecular hydrogen exists in two isomeric forms, depending on the spin of each proton nucleus in the molecule: in orthohydrogen, both protons spin in the same direction, whereas in parahydrogen, the protons spin in opposite directions. Eisenberg’s group demonstrated that NMR spectroscopy—a technique used to determine the structures of molecules in solution—could be enhanced by introducing parahydrogen into the target molecule (9, 10). Eisenberg’s early work primarily made fundamental contributions to our understanding of inorganic chemistry, but was not motivated by the potential practical applications of those discoveries. That began to change in the early 1980s, when Eisenberg attended Zeliadt
a lecture about photoelectrochemistry—the production of light using electrochemistry— given by chemist Allen Bard. Eisenberg was fascinated by the topic, and asked Bard about the components needed for photoelectrochemistry. Bard told him that the most important component was a luminescent compound. At his first opportunity, Eisenberg rifled through the drawers of his laboratory in the dark, shining a UV lamp on everything he could find. He quickly discovered that several of the metal dithiolene compounds that his laboratory had synthesized over the years were brightly luminescent (11–13). Eisenberg began thinking about potential applications for these luminescent compounds. It had long been known that when a luminescent compound absorbs a photon of light, it is promoted to an excited state that can be a stronger electron donor and a stronger electron acceptor than the ground state. Therefore, such compounds can be used to oxidize or reduce other molecules after exposure to light. Eisenberg decided to see if he could use his luminescent dithiolene complexes as photocatalysts to split water into hydrogen and oxygen. He began by characterizing and optimizing luminescent complexes containing platinum (13–15), and ultimately succeeded in generating hydrogen from water using a platinum terpyridyl complex (16). Because platinum is a rare precious metal and therefore expensive, Eisenberg investigated organic dyes as possible replacements for the platinum-based light absorber in his photocatalytic systems. He found that the organic dyes were more efficient at generating hydrogen than the platinumbased systems but quickly decomposed after continuous exposure to light (17, 18). “Therefore, we needed to figure out another kind of light absorber,” Eisenberg says. He began collaborating with a fellow chemist at the University of Rochester, Todd Krauss, an expert on luminescent nanocrystals known as quantum dots. Together, the pair developed a photocatalytic system for hydrogen generation using a quantum dot made of cadmium selenide coated with a capping agent. “The light absorber is like an M&M,” Eisenberg explains. “The chocolate part is the quantum dot, and the coating consists of molecules that make the M&M dissolve in water.” Eisenberg and Krauss demonstrated that their photocatalytic system that used quantum dots produced hydrogen for more than 2 weeks— a significant improvement over previous systems, which only lasted for hours or days (19). In his Inaugural Article, Eisenberg’s team further optimized the efficiency of
hydrogen production using a capping agent that attaches to the quantum dot more strongly, enabling the study of different catalysts for making H2. Communicating and Collaborating
Outside the laboratory, Eisenberg served as the editor-in-chief for the journal Inorganic Chemistry from 2001 until 2013. During that time, he reflected on the role of communication in science. “Our whole system is built on sharing knowledge,” Eisenberg says. “Communication is the way that you can share knowledge. When you do an experiment, it is essential to communicate that, and to communicate it clearly. So I think that [communication] is something that has always been important to me, in terms of journal articles, but it is also important in terms of teaching.” Eisenberg says he has always enjoyed teaching and strives to make chemistry enjoyable for his students. One course that he created with University of Rochester colleague James Farrar put all of the subjects of freshman chemistry into the context of energy and the environment. Over the course of his career, he has received numerous accolades for his teaching, including the Lifetime Achievement Award in Graduate Education from the University of Rochester, and the Nobel Laureate Signature Award in Graduate Education from the American Chemical Society—an award that he shared with his former graduate student, Pingwu Du. “That was a real delight,” Eisenberg says, “because there is a close relationship between an advisor and the student working with him or her. And really, it’s that person’s success that, as an advisor, we really enjoy, because we’ve helped that person move along and fulfill his or her potential.” As for his future research endeavors, Eisenberg says that he will continue to focus primarily on questions related to light-driven generation of hydrogen. “I can see that this problem has lots of importance, substance, and nuance to it.” However, he acknowledges that his role will shift from being the principal investigator to being a coprincipal investigator or a collaborator. “There’s a role for senior scientists in terms of how we use our knowledge,” Eisenberg explains. “We have a lot invested in our careers and in what we do, but we can’t continue to be the top dogs, because otherwise we soak up resources that are really important for younger people to obtain to grow their careers.” In recent years, Eisenberg has developed productive collaborations with several of his younger colleagues. “That’s something I hope to continue to do.”
PNAS | November 12, 2013 | vol. 110 | no. 46 | 18347
1 ACS Pressroom (2012) Voices of inorganic chemistry featuring Richard Eisenberg. Inorganic Chemistry. Available at http://vimeo. com/31143999. Accessed October 4, 2013. 2 Eisenberg R (2009) Chemistry. Rethinking water splitting. Science 324(5923):44–45. 3 Das A, Han Z, Haghighi MG, Eisenberg R (2013) Photogeneration of hydrogen from water using CdSe nanocrystals demonstrating the importance of surface exchange. Proc Natl Acad Sci USA 110(42): 16716–16723. 4 Eisenberg R, Ibers JA, Clark RJH, Gray HB (1964) Molecular and electronic structure of the bis(maleonitriledithiolato)nickelate(II) ion. J Am Chem Soc 86(1):113–115. 5 Eisenberg R, Ibers JA (1965) Trigonal prismatic coordination. The molecular structure of tris(cis-1,2-diphenylethene-1,2-dithiolato) rhenium. J Am Chem Soc 87(16):3776–3778. 6 Pierpont CG, VanDerveer DG, Durland W, Eisenberg R (1970) Ruthenium complex having both linear and bent nitrosyl groups. J Am Chem Soc 92(15):4760–4762. 7 Cheng C-H, Hendriksen DE, Eisenberg R (1977) Homogeneous catalysis of the water gas shift reaction using rhodium carbonyl iodide. J Am Chem Soc 99(8):2791–2792.
18348 | www.pnas.org/cgi/doi/10.1073/pnas.1319293110
8 Baker EC, Hendriksen DE, Eisenberg R (1980) Mechanistic studies of the homogeneous catalysis of the water gas shift reaction by rhodium carbonyl iodide. J Am Chem Soc 102(3): 1020–1027. 9 Eisenberg R (1991) Parahydrogen-induced polarization: A new spin on reactions with H2 . Acc Chem Res 24(4): 110–116. 10 Eisenschmid TC, et al. (1987) Para hydrogen induced polarization in hydrogenation reactions. J Am Chem Soc 109(26): 8089–8091. 11 Johnson CE, Eisenberg R, Evans TR, Burberry MS (1983) Luminescent iridium(I), rhodium (I), and platinum(II) dithiolate complexes. J Am Chem Soc 105(7):1795–1802. 12 Zuleta JA, Chesta CA, Eisenberg R (1989) Square-planar complexes of platinum(II) that luminesce in fluid solution. J Am Chem Soc 111(24):8916–8917. 13 Cummings SD, Eisenberg R (1996) Tuning the excited-state properties of platinum(II) diimine dithiolate complexes. J Am Chem Soc 118(8):1949–1960. 14 Huertas S, Hissler M, McGarrah JE, Lachicotte RJ, Eisenberg R (2001) Syntheses and structural characterization of luminescent
platinum(II) complexes containing di-tert-butylbipyridine and new 1,1-dithiolate ligands. Inorg Chem 40(6):1183–1188. 15 Chakraborty S, Wadas TJ, Hester H, Schmehl R, Eisenberg R (2005) Platinum chromophore-based systems for photoinduced charge separation: a molecular design approach for artificial photosynthesis. Inorg Chem 44(20):6865–6878. 16 Du P, Schneider J, Jarosz P, Eisenberg R (2006) Photocatalytic generation of hydrogen from water using a platinum(II) terpyridyl acetylide chromophore. J Am Chem Soc 128(24): 7726–7727. 17 Lazarides T, et al. (2009) Making hydrogen from water using a homogeneous system without noble metals. J Am Chem Soc 131(26):9192–9194. 18 McCormick TM, et al. (2010) Reductive side of water splitting in artificial photosynthesis: new homogeneous photosystems of great activity and mechanistic insight. J Am Chem Soc 132(44): 15480–15483. 19 Han Z, Qiu F, Eisenberg R, Holland PL, Krauss TD (2012) Robust photogeneration of H 2 in water using semiconductor nanocrystals and a nickel catalyst. Science 338(6112): 1321–1324.
Zeliadt
Profile of Richard Eisenberg Nicholette Zeliadt Science Writer
If Richard Eisenberg hadn’t accidentally spilled the flask containing a red, corrosive liquid one day in 1963, he might not have become the accomplished inorganic chemist he is today. Back then, as an undergraduate at Columbia University in New York City, he set about synthesizing an organometallic vanadium compound (1). However, to do that, he first had to make vanadium tetrachloride, a highly reactive liquid that gives off fumes of hydrochloric acid when exposed to moisture. On that day in 1963, Eisenberg had succeeded in generating a precious amount of vanadium tetrachloride when he dropped the flask, spilling its contents all over the fume hood of the laboratory. As a result of that incident, Eisenberg decided to take a break from synthesis and began using X-ray crystallography to analyze the structures of molecules made by others. Although he did not realize it at the time, this fortuitous turn of events ultimately led him down a fruitful path of research and discovery. In the decades that followed, Eisenberg— a professor of chemistry at the University of Rochester and a recently elected member of the National Academy of Sciences (NAS)— proceeded to make significant contributions to our understanding of the structure–function relationships of inorganic and organometallic compounds. Along the way, he became interested in applying his skills and knowledge toward what he calls the greatest scientific and technological challenge of the 21st century that is not directly related to human health: developing renewable energy for sustainable development on a global scale. Projected increases in global energy needs “can be met satisfactorily by only one kind of alternative energy—the Sun,” Eisenberg wrote in a 2009 Science article (2). One approach to harvesting sunlight for renewable energy involves mimicking the ability of green plants and other photosynthetic organisms to store the energy of sunlight in chemical bonds—an approach known as artificial photosynthesis, which is based on the light-driven splitting of water into hydrogen and oxygen. In his Inaugural Article, Eisenberg describes a highly active and robust artificial photosynthetic system for converting the protons in water to hydrogen gas, an attractive fuel that can be
readily converted into electrical energy and produces no carbon dioxide on combustion, in contrast with all other fuels (3). Science in the City
A native New Yorker, Eisenberg grew up in the Bronx near Yankee Stadium, which helped to foster his long-standing love for the New York Yankees. His inquisitive young mind began to take an interest in science after he read about the planets and solar system in The Book of Knowledge. Eisenberg recalls taking a couple of chemistry classes while he was a student at Bayside High School in Queens, but says he did not become seriously interested in chemistry until he arrived at Columbia University in 1959, at the age of 16. During his first year at Columbia, Eisenberg says that he and his chemistry classmates “were just hanging on by our fingernails.” However, by his second year, he discovered that he enjoyed organic chemistry, in particular learning how to build and synthesize molecules and understanding their properties based on their functional groups. Subsequent coursework in physical chemistry gave him insight into the principles of how molecules hold together and how collections of molecules behave. “All of this sounded great,” Eisenberg says, “but what really sealed the deal for me in chemistry was when I met Harry Gray.” At the beginning of 1963, Eisenberg was finishing his senior year in college and had decided that he wanted to try his hand at research. One of Eisenberg’s classmates, John Alexander, was working in the laboratory of Harry Gray, who was then a young assistant professor of chemistry at Columbia, and urged Eisenberg to talk with Gray about working on a research project in Gray’s laboratory. Eisenberg had always been intimidated by faculty, but as soon as he stepped into Gray’s office, his fears subsided. “Harry looked up and said, ‘Rich, I’ve been waiting to see you, we’ve got some great stuff going,’” Eisenberg recalls. Back then, Gray’s laboratory was investigating the electronic structures of inorganic metal complexes to understand their vivid colors and magnetic properties. For his
18346–18348 | PNAS | November 12, 2013 | vol. 110 | no. 46
Richard Eisenberg. Image courtesy of Marcia Eisenberg.
senior research project, Eisenberg worked on synthesizing an organometallic vanadium complex, the precursor of which ended up spilled in the fume hood. He later decided to continue working in Gray’s laboratory while he pursued his PhD. “[Gray’s] enthusiasm and interest in science were really just contagious,” Eisenberg explains. “I liked the exploration of finding something new.” From Synthesis to Crystallography
For his graduate research, Eisenberg sought to determine the crystal structures of some of the brightly colored molecules synthesized in Gray’s laboratory. He went to Brookhaven National Laboratory in Upton, NY, to learn how to do X-ray crystallography from chemist James Ibers, who later moved to Northwestern University in Evanston, IL, in 1965. At that time, X-ray crystallography was less automated than it is today, and it took about 6 weeks for Eisenberg to collect his data. However, by the middle of his first year in graduate school, Eisenberg had determined the first crystal structure of a so-called metal dithiolene complex, forming the basis for his first publication (4). The metal dithiolene complex that Eisenberg studied was one of a class of molecules of great interest to Gray and other chemists This is a Profile of a recently elected member of the National Academy of Sciences to accompany the member’s Inaugural Article on page 16716 in issue 42 of volume 110.
www.pnas.org/cgi/doi/10.1073/pnas.1319293110
PROFILE
in the 1960s because of their unusual redox and magnetic properties and colors. A dithiolene is a group of connected atoms that acts as a ligand to bind to a metal ion through two sulfur atoms. Back then, many chemists thought that complexes containing three dithiolene ligands attached to the metal ion would adopt an octahedral molecular geometry, which at the time was the only known geometry for metal ions bound to six atoms. However, Eisenberg’s crystal structures revealed that complexes containing three dithiolene ligands adopt a trigonal prismatic geometry (5). In 1967, at the age of 24, Eisenberg completed his PhD and, with a grant from the National Science Foundation, continued his work on the structures of metal complexes as an assistant professor at Brown University in Providence, RI. Although he always maintained an interest in dithiolene complexes, he began studying the structures of metal nitrosyl complexes, which contain a metal atom bound to nitric oxide (NO). His crystal structures revealed the geometry of the metal–NO bond in several different metal complexes and illustrated how the metal– NO arrangement can shift between linear and bent geometries (6). A Shift in Approach
In 1974, Eisenberg accepted a position at the University of Rochester in Rochester, NY, to establish an inorganic chemistry program there. He directed his research efforts toward catalysis. He first studied the reduction of NO and then worked on a reaction known as the water gas shift reaction, which converts water and carbon monoxide to hydrogen gas and carbon dioxide—a reaction that had been used industrially as part of a process to make long chain hydrocarbons from coal (7, 8). His laboratory also studied reactions involving the addition of molecular hydrogen, H2, to metal complexes and organic molecules. Molecular hydrogen exists in two isomeric forms, depending on the spin of each proton nucleus in the molecule: in orthohydrogen, both protons spin in the same direction, whereas in parahydrogen, the protons spin in opposite directions. Eisenberg’s group demonstrated that NMR spectroscopy—a technique used to determine the structures of molecules in solution—could be enhanced by introducing parahydrogen into the target molecule (9, 10). Eisenberg’s early work primarily made fundamental contributions to our understanding of inorganic chemistry, but was not motivated by the potential practical applications of those discoveries. That began to change in the early 1980s, when Eisenberg attended Zeliadt
a lecture about photoelectrochemistry—the production of light using electrochemistry— given by chemist Allen Bard. Eisenberg was fascinated by the topic, and asked Bard about the components needed for photoelectrochemistry. Bard told him that the most important component was a luminescent compound. At his first opportunity, Eisenberg rifled through the drawers of his laboratory in the dark, shining a UV lamp on everything he could find. He quickly discovered that several of the metal dithiolene compounds that his laboratory had synthesized over the years were brightly luminescent (11–13). Eisenberg began thinking about potential applications for these luminescent compounds. It had long been known that when a luminescent compound absorbs a photon of light, it is promoted to an excited state that can be a stronger electron donor and a stronger electron acceptor than the ground state. Therefore, such compounds can be used to oxidize or reduce other molecules after exposure to light. Eisenberg decided to see if he could use his luminescent dithiolene complexes as photocatalysts to split water into hydrogen and oxygen. He began by characterizing and optimizing luminescent complexes containing platinum (13–15), and ultimately succeeded in generating hydrogen from water using a platinum terpyridyl complex (16). Because platinum is a rare precious metal and therefore expensive, Eisenberg investigated organic dyes as possible replacements for the platinum-based light absorber in his photocatalytic systems. He found that the organic dyes were more efficient at generating hydrogen than the platinumbased systems but quickly decomposed after continuous exposure to light (17, 18). “Therefore, we needed to figure out another kind of light absorber,” Eisenberg says. He began collaborating with a fellow chemist at the University of Rochester, Todd Krauss, an expert on luminescent nanocrystals known as quantum dots. Together, the pair developed a photocatalytic system for hydrogen generation using a quantum dot made of cadmium selenide coated with a capping agent. “The light absorber is like an M&M,” Eisenberg explains. “The chocolate part is the quantum dot, and the coating consists of molecules that make the M&M dissolve in water.” Eisenberg and Krauss demonstrated that their photocatalytic system that used quantum dots produced hydrogen for more than 2 weeks— a significant improvement over previous systems, which only lasted for hours or days (19). In his Inaugural Article, Eisenberg’s team further optimized the efficiency of
hydrogen production using a capping agent that attaches to the quantum dot more strongly, enabling the study of different catalysts for making H2. Communicating and Collaborating
Outside the laboratory, Eisenberg served as the editor-in-chief for the journal Inorganic Chemistry from 2001 until 2013. During that time, he reflected on the role of communication in science. “Our whole system is built on sharing knowledge,” Eisenberg says. “Communication is the way that you can share knowledge. When you do an experiment, it is essential to communicate that, and to communicate it clearly. So I think that [communication] is something that has always been important to me, in terms of journal articles, but it is also important in terms of teaching.” Eisenberg says he has always enjoyed teaching and strives to make chemistry enjoyable for his students. One course that he created with University of Rochester colleague James Farrar put all of the subjects of freshman chemistry into the context of energy and the environment. Over the course of his career, he has received numerous accolades for his teaching, including the Lifetime Achievement Award in Graduate Education from the University of Rochester, and the Nobel Laureate Signature Award in Graduate Education from the American Chemical Society—an award that he shared with his former graduate student, Pingwu Du. “That was a real delight,” Eisenberg says, “because there is a close relationship between an advisor and the student working with him or her. And really, it’s that person’s success that, as an advisor, we really enjoy, because we’ve helped that person move along and fulfill his or her potential.” As for his future research endeavors, Eisenberg says that he will continue to focus primarily on questions related to light-driven generation of hydrogen. “I can see that this problem has lots of importance, substance, and nuance to it.” However, he acknowledges that his role will shift from being the principal investigator to being a coprincipal investigator or a collaborator. “There’s a role for senior scientists in terms of how we use our knowledge,” Eisenberg explains. “We have a lot invested in our careers and in what we do, but we can’t continue to be the top dogs, because otherwise we soak up resources that are really important for younger people to obtain to grow their careers.” In recent years, Eisenberg has developed productive collaborations with several of his younger colleagues. “That’s something I hope to continue to do.”
PNAS | November 12, 2013 | vol. 110 | no. 46 | 18347
1 ACS Pressroom (2012) Voices of inorganic chemistry featuring Richard Eisenberg. Inorganic Chemistry. Available at http://vimeo. com/31143999. Accessed October 4, 2013. 2 Eisenberg R (2009) Chemistry. Rethinking water splitting. Science 324(5923):44–45. 3 Das A, Han Z, Haghighi MG, Eisenberg R (2013) Photogeneration of hydrogen from water using CdSe nanocrystals demonstrating the importance of surface exchange. Proc Natl Acad Sci USA 110(42): 16716–16723. 4 Eisenberg R, Ibers JA, Clark RJH, Gray HB (1964) Molecular and electronic structure of the bis(maleonitriledithiolato)nickelate(II) ion. J Am Chem Soc 86(1):113–115. 5 Eisenberg R, Ibers JA (1965) Trigonal prismatic coordination. The molecular structure of tris(cis-1,2-diphenylethene-1,2-dithiolato) rhenium. J Am Chem Soc 87(16):3776–3778. 6 Pierpont CG, VanDerveer DG, Durland W, Eisenberg R (1970) Ruthenium complex having both linear and bent nitrosyl groups. J Am Chem Soc 92(15):4760–4762. 7 Cheng C-H, Hendriksen DE, Eisenberg R (1977) Homogeneous catalysis of the water gas shift reaction using rhodium carbonyl iodide. J Am Chem Soc 99(8):2791–2792.
18348 | www.pnas.org/cgi/doi/10.1073/pnas.1319293110
8 Baker EC, Hendriksen DE, Eisenberg R (1980) Mechanistic studies of the homogeneous catalysis of the water gas shift reaction by rhodium carbonyl iodide. J Am Chem Soc 102(3): 1020–1027. 9 Eisenberg R (1991) Parahydrogen-induced polarization: A new spin on reactions with H2 . Acc Chem Res 24(4): 110–116. 10 Eisenschmid TC, et al. (1987) Para hydrogen induced polarization in hydrogenation reactions. J Am Chem Soc 109(26): 8089–8091. 11 Johnson CE, Eisenberg R, Evans TR, Burberry MS (1983) Luminescent iridium(I), rhodium (I), and platinum(II) dithiolate complexes. J Am Chem Soc 105(7):1795–1802. 12 Zuleta JA, Chesta CA, Eisenberg R (1989) Square-planar complexes of platinum(II) that luminesce in fluid solution. J Am Chem Soc 111(24):8916–8917. 13 Cummings SD, Eisenberg R (1996) Tuning the excited-state properties of platinum(II) diimine dithiolate complexes. J Am Chem Soc 118(8):1949–1960. 14 Huertas S, Hissler M, McGarrah JE, Lachicotte RJ, Eisenberg R (2001) Syntheses and structural characterization of luminescent
platinum(II) complexes containing di-tert-butylbipyridine and new 1,1-dithiolate ligands. Inorg Chem 40(6):1183–1188. 15 Chakraborty S, Wadas TJ, Hester H, Schmehl R, Eisenberg R (2005) Platinum chromophore-based systems for photoinduced charge separation: a molecular design approach for artificial photosynthesis. Inorg Chem 44(20):6865–6878. 16 Du P, Schneider J, Jarosz P, Eisenberg R (2006) Photocatalytic generation of hydrogen from water using a platinum(II) terpyridyl acetylide chromophore. J Am Chem Soc 128(24): 7726–7727. 17 Lazarides T, et al. (2009) Making hydrogen from water using a homogeneous system without noble metals. J Am Chem Soc 131(26):9192–9194. 18 McCormick TM, et al. (2010) Reductive side of water splitting in artificial photosynthesis: new homogeneous photosystems of great activity and mechanistic insight. J Am Chem Soc 132(44): 15480–15483. 19 Han Z, Qiu F, Eisenberg R, Holland PL, Krauss TD (2012) Robust photogeneration of H 2 in water using semiconductor nanocrystals and a nickel catalyst. Science 338(6112): 1321–1324.
Zeliadt
