what's a company to do with $1.7 billion?
TRANSCRIPT
NEWS OF THE WEEK
N A N O S C I E N C E
ROSETTE NANOTUBES Self-assembling structures grow longer in water as the temperature is raised
ROSETTE NANOTUBES, A NEW
class of organic nanotubes, are proving to have unusu
al properties that may make them important players in future nano-technologies.
Hicham Fenniri, an assistant professor of chemistry at Purdue University, and his colleagues have found that, contrary to the usual expectations, the self-assembly of these nanotubes in water is promoted by heat [Proc. Natl. Acad. Sci. USA, published online March 12, http://www.pnas. org/cgi/doi/10.1073/pnas.032527 099].
The Purdue chemists also have found that rosette nanotubes can serve as scaffolds for the spontaneous formation of channellike assemblies on their periphery. Such assemblies could be used to produce new materials, molecular electronic or photonic devices, and drug delivery systems, for instance.
The rosette nanotubes are assembled from a single building block—a bicyclic molecule that, by design, has a hydrogen-bond
donor-donor-acceptor array on one side and a complementary acceptor-acceptor-donor array on the other side. These building blocks hydrogen-bond to form a rosette. The rosettes then stack to form a stable nanotube with a hollow core 11A across and up to several micrometers long. The tube's structure is maintained by electrostatic, hydrophobic, and stacking interactions.
Fenniri and coworkers can attach to the building block a variety of functional groups, such as crown ethers, which can bind other molecules. W h e n the rosettes stack to form the nanotube, the crown ethers on alternate rosettes line up, forming 12 additional channels on the outside of the nanotube that can serve, say, as conduits for ions.
By modifying the building block and the functional groups attached to it, the team of Purdue chemists can adjust both the dimensions and properties of the nanotube.
The team's most striking observation is that higher tempera-
v
Û v ,
tures lead to longer tubes, an example of entropy-driven self-assembly Such processes are well known in aqueous protein systems and even for certain small molecules in organic solvents. But this is the first time that entrop-ically driven self-assembly has been reported for synthetic molecular systems in water, Fenniri says. —RON DAGANI
B U S I N E S S
What's A Company To Do With $1.7 Billion?
I CH·
ts
I
< ALL TOGETHER I NOW Molecules (top) < having an array of I hydrogen-bond donor © and acceptor sites I (red and blue arrows,
respectively) and a crown ether-containing substituent (R) assemble themselves into a six-membered macrocy-clic rosette (top left) held together by 18 hydrogen bonds. The rosettes then stack to form a nanotube with peripheral channels formed by the crown ethers.
L ast week, Hercules Chairman and CEO William H. Joyce provided an answer as he described
how the company wil l allocate the money it is getting from the sale of its BetzDear-born water treatment business to General Electric. In short, it wil l pay down the mountain of debt it took on when it acquired BetzDearborn.
Of the approximately $1.8 billion that GE wil l pay for the business, Hercules wil l net about $1.67 billion. Of that, about $1.59 billion wil l go toward reducing debt to about $1.30 billion, including preferred
securities. The remaining $75 million wil l be used as collateral for currently outstanding letters of credit.
With the sale of BetzDearborn, the focus at Hercules is on improving shareholder value, including continuing the company's cost reduction program. The sale wil l reduce Hercules' revenues by about 36%, but it is expected to enable annual cost savings of $25 million by simplifying work processes and the overall corporate structure needed to support a less complex organization, according to Joyce.
Restructuring efforts apparently have replaced the sale of the company as the prime goal at Hercules. Joyce says, "We're looking at all sorts of alternatives, and one of these clearly has to be running the company as it stands right now." The sale of BetzDearborn leaves Hercules with four main businesses: Aqualon aqueous systems; Fibers-Visions synthetic fibers; pulp and paper chemicals, including paper process chemicals retained from BetzDearborn; and resins and terpenes.—WILLIAM STORCK
HTTP: / /PUBS.ACS.ORG/CEN C & E N / M A R C H 1 8 , 2 0 0 2 9