NEWS OF THE WEEK ORGANOMETALLICS
SUPERSIZED SANDWICHES Aromatic hydrocarbon ligands flank metal monolayers in stable complexes gle-metal metallocenes may soon start to look like the dieter's option in the menu of sandwich complexes. Overstuffed
chemists Tetsuro Murahashi and Hideo Kurosawa, created two of these novel compounds. In the simpler structure, chloride ions cap a triangular array of three
sandwich complexes, filled with a monolayer of metal atoms, have been isolated for the first time by researchers at Japan's Osaka University and Kyoto University (Science 2006,313,1104). The team, led by Osaka-based
palladium atoms, which are sandwiched between two cycloheptatrienyl ligands. The other complex resembles a submarine sandwich, with its planar array of five palladium atoms nestled between two polycyclic naphthacene ligands.
F
ERROCENE AND OTHER SIN-
The surprisingly stable compounds can be handled in air, and the simpler compound worked well as a cross-coupling catalyst in preliminary tests. Murahashi points out that the use ofpalladium as the metal filling is remarkable because palladium isn't regularly used in sandwich chemistry. "The concept of making discrete monodisperse 'supersandwiches' with alternating organic and metallic layers has been around for decades," comments metallocene expert K. Peter C. Vollhardt of the University of
PALLADIUM PACKED Novel overstuffed sandwiches feature monolayers of palladium atoms (gold) between aromatic hydrocarbon ligands (blue = C, white = H, green = CI).
POLLUTION
China Launches Huge Water Quality Study
C
hina's State Environmental Protection Administration (SEPA) will spend hundreds of millions of dollars—perhaps billions— on a 15-year study of Chinese water quality as part of a larger plan to spend $125 billion to improve water security and build sewage treatment systems. A news item posted on the SEPA website notes that 90% of the water running through Chinese cities is polluted and that 300 million Chinese do not have access to clean water. The study will look into "drinkable water security, environmental improvement of river basins, and urban water pollution treatment." SEPA Minister Zhou Shengxian, speaking at a conference, told attendees that the study will be the largest-ever environmental study conducted 8
C & E N / AUGUST 2 8 . 2006
in China. As part of its mandate, the study will develop new clean water technologies. Another item posted on an official Chinese government website says the country will spend $41 billion in the next four years to build sewage treatment plants in urban areas throughout the country. And the government has already begun work on a previously announced river water diversion project that is the costliest part of the $125 billion spending plan. Earlier Chinese government attempts to improve water quality have not been effective. A high-profile, 10-year program to clean up the Huai River, one of China's most polluted, ended in failure, the government admitted last year (C&EN, Sept. 26,2005, page 2D.-JEAN-FRANQ0IS TREMBLAY
California, Berkeley. "Murahashi and Kurosawa's group is the first to demonstrate itsfeasibilityin a synthetic approach that is startling in its simplicity and highly aesthetically pleasing in its outcome." Murahashi says he and his colleagues hope to learn more about supersandwiches' fundamental properties by synthesizing a wide range of the compounds, including mixed-metal systems and complexes that employ other unsaturated hydrocarbon ligands. "We believe that different sizes and shapes of monolayer metal sheets could be formed, particularly when different planar carbocyclic ligands are used," he says. "We also expect that different metals can be used" because many metals form simple metallocenes. "This work is a beautiful illustration of how fundamental research provides a foundation for possible conceptual and concrete advances in catalysis and materials research," Vollhardt concludes.— BETHANY HALFORD WWW.CEN-0NLINE.ORG
