Shortest Chemical Bond Between Metals-world
record set by UD researchers
[Nov 21]NEWARK,DE,USA--Chemists from the University
of Delaware, in collaboration with a colleague at the University
of Wisconsin, have set a new world record for the shortest chemical
bond ever recorded between two metals, in this case, two atoms of
chromium. Photo:Klaus Theopold, professor and chairperson
of the UD Department of Chemistry and Biochemistry
(enlarge
photo)
The distance? A minuscule 1.803 Ångstroms, which
is on the order of a billionth of the thickness of a human hair.
The chemists weren't driven by the Guinness Book of
World Records or even a friendly bet. As is often the case in science,
they discovered the molecule, which has a quintuple (i. e., five-fold)
bond, quite by accident.
“Sometimes things like this just happen,” said Klaus
Theopold, professor and chairperson of the UD Department of Chemistry
and Biochemistry.
Theopold and Kevin Kreisel, who graduated with his
doctorate from UD in August and is now a postdoctoral researcher
at the University of Wisconsin, made the finding, working with research
associate Glenn Yap and postdoctoral fellow Olga Dmitrenko, both
from UD, and Clark Landis, a colleague from the University of Wisconsin.
The research was reported in the Journal of the American
Chemical Society. Theopold has been researching the chemistry of
chromium for a long time.
The metal is an important industrial catalyst for making
plastics such as polyethylene. “We discovered this interesting looking
molecule and realized that it had an extremely short distance between
the metal atoms,” Theopold said.
Photo:
This graphic depicts the bond between two atoms of chromium that
has set a new record for the shortest chemical bond ever found between
two metals. (enlarge
photo)
Using an analytical technique called X-ray
diffraction, the scientists were able to look directly at the atomic
structure of the new molecule and measure the distance between the
chromium atoms.
A rule-of-thumb in chemistry, Theopold said,
is that bond length and bond strength go together, so it's likely
that the metal-metal bond is a strong one, although Theopold said
no one knows for sure.
“This molecule is probably not practically useful.
We're not going to get a patent here or cure cancer,” Theopold noted.
“Records define the range in which things can exist. It's just an
interesting molecule from a fundamental scientific standpoint.”
And those teeny-tiny bonds do mark a new world record
for chemistry. Before the UD discovery, Theopold said, the last
record, achieved by researchers at Texas A&M University, stood for
nearly 30 years.
