The previously elusive methanediol molecule of importance to the organic,
atmospheric science and astrochemistry communities has been synthetically
produced for the first time by University of Hawaiʻi at Mānoa researchers.
Their discovery and methods were published in Proceedings of the National
Academy of Sciences on December 30.
Methanediol is also known as formaldehyde monohydrate or methylene glycol.
With the chemical formula CH2(OH)2, it is the simplest geminal diol, a molecule which carries two hydroxyl
groups (OH) at a single carbon atom. These organic molecules are suggested
as key intermediates in the formation of aerosols and reactions in the ozone
layer of the atmosphere.
The research team—consisting of Department of Chemistry Professor Ralf
Kaiser, postdoctoral researchers Cheng Zhu, N. Fabian Kleimeier and Santosh
Singh, and W.M. Keck Laboratory in Astrochemistry Assistant Director Andrew
Turner—prepared methanediol via energetic processing of extremely low
temperature ices and observed the molecule through a high-tech mass
spectrometry tool exploiting tunable vacuum photoionization (the process in
which an ion is formed from the interaction of a photon with an atom or
molecule) in the W.M. Keck Laboratory in Astrochemistry. Electronic
structure calculations by University of Mississippi Associate Professor Ryan
Fortenberry confirmed the gas phase stability of this molecule and
demonstrated a pathway via reaction of electronically excited oxygen atoms
with methanol.
The findings, researchers said, advances their perception of the fundamental
chemistry and chemical bonding of geminal diols and signifies their role as
a key player in atmospheric and interstellar environments. Astronomers may
now be able to use radio telescopes to identify elusive molecules, such as
methanediol, in deep space.
This versatile strategy to first synthesize molecules, such as geminal
diols, prior to their search in star forming regions, may eventually bring
us closer to an understanding of the molecular structure and chemical
bonding of exotic organic molecules, which according to textbooks "should
not exist." The authors are also planning the investigation of the stability
and preparation of methanetriol [CH(OH)3] and methanetetraol [C(OH)4].
Reference:
Cheng Zhu et al, Synthesis of methanediol [CH2(OH)2]: The simplest geminal diol, Proceedings of the National Academy of
Sciences (2021).
DOI: 10.1073/pnas.2111938119