NEWS OF THE WEEK IN BRIEF: BABY PICTURE This picture of the early universe—when it was about 200 million years old—captures the after glow of the big bang and gives a new estimate for its age: 13.7 billion years. The image was made by NASA scientists using the Wilkinson Microwave Anisotropy Probe, which NASA says has a 1% error margin.
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GREENHOUSE GAS EMISSIONS PLAN Energy Department announces guide for cutting emissions intensity
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T THE DEPARTMENT OF
energy last week, govern ment officials and corpo rate leaders showcased what they called a significant commitment to a voluntary program for re ducing greenhouse gases. Energy Secretary Spencer Abraham an nounced the program, which is meant to reduce the growth of U.S. greenhouse gas emissions. The plan, Abraham said, is an attempt to achieve President George W Bush's goal of reduc ing greenhouse gas intensity—
the ratio ofgreenhouse gas emis sions to economic output—by 18% over the next decade. Numerous industrial initiatives were announced at the DOE gath ering. EPA Administrator Christinelbdd Whitman, for example, said the magnesium industry has promised to eliminate emissions of sulfur hexafluoride by 2010. Edison Electric Institute and six other power sector groups an nounced plans to reduce C 0 2 emissions by 3 to 5% during this decade. And American Chemistry
Council members have agreed to an 18% reduction in greenhouse gas intensityfrom1990 levels by 2012, said George A. Walczak, industry relations manager at No va Chemicals. DOE projects a 14% reduction in greenhouse gas intensity be tween 2002 and 2012 without special efforts to reduce emissions and says total greenhouse gas emissions will increase 14% over the decade even if the President's goal is reached Opponents ofthe policy point out that the intensi ty of the overall U.S. economy de clined 17.5% from 1990 to 2000 under business as usual even as greenhouse gas emissions in creased. Bush's plan "uses a de ceptive accounting tactic to cam ouflage continued pollution growth at the same unsafe rate as today and possibly even faster," the Natural Resources Defense Council says.-ΒΕπΕ HILEMAN
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SUPRAMOLECULAR
CHIRALITY
The structure acts as a nanoscale flask, inside which guest molecules can react. Raymonds' group has been able to remove the ligands one at a time and re place them with a similar bis-catecholate ligand. Aside from its inherent cu riosity Raymond says chiral struc tural memory could also prove useful in the design of molecularWhile the structure's ligands flask chiral catalysis, an idea he's are achiral, the system retains its pursuing with UC Berkeley original chirality, even after a li- chemistry professor Robert G. gand is replaced. University of Bergman. California, Berkeley, chemistry A number of groups have de professor Kenneth N. Raymond, vised molecules with structural postdoc Marco Ziegler, and grad memory, but in those examples, uate students Anna V. Davis and the assemblies' chirality stemmed Darren W. Johnson discovered from chiral ligands. Replacing the this property in their chiral tetra components with achiral ligands hedral structure, in which sixbis- then caused structures to assem catecholate ligand edges span ble into a racemic mixture. four gallium(111) vertices [Angew. The Raymond group's strate Chem. Int. Ed. 42,665 (2003)}. gy "is avery interesting and smart "This is a very nice example of approach," says Eiji Yashima, a structural and chiral memory," professor in the department of says Robert Purrello, chemistry molecular design and engineer professor at the University of ing at Nagoya University, in Japan.-ELIZABETH WILSON Catania, in Italy
STRUCTURAL MEMORY LONG-TERM MEMORY Tetrahedral supramolecular structure keeps its chirality and shape, Λ even when V ligands are replaced.
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Chiral assemblies retain shape even after their parts are replaced
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Ν ENTIRE BUILDING CAN
be rebuilt by removing a sin gle board at a time and re placing it with a new one. Chemists have now shown that anovel supramolecular as sembly has this same"structural memory," but with a couple of intriguing twists: The replacement molecular "boards" can dif ferfromthe origi nals without affect^ ^ ing the structure.
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