PERIODIC TABLE
Names proposed for new elements
113
Nh Mc Nihonium
Nihonium, moscovium, tennessine, and oganesson are likely to appear on the periodic table Nihonium, moscovium, tennessine, and oganesson are the recommended names for elements 113, 115, 117, and 118, respectively, the International Union of Pure & Applied Chemistry (IUPAC) announced on June 8. IUPAC officially added the elements to the periodic table at the end of 2015. Those credited with discovering the elements get the rights to propose permanent names and symbols. The names will be finalized after public review and formal approval by the IUPAC Council. According to recommendations published by IUPAC in April, elements can be named after a mythological concept, a mineral, a place or country, a property, or a scientist (Pure Appl. Chem. 2016, DOI: 10.1515/pac-2015-0802). Element names should also “have an ending that reflects
115
and maintains historical and chemical consistency,” the recommendations say. Japan’s RIKEN research institution was credited with discovering element 113. Nihonium (Nh) comes from Nihon, which is one of two ways to say “Japan” in Japanese. It is the first element discovered in and named after an Asian country. The discoveries of the other three elements were credited to European-American collaborations involving Russia’s Joint Institute for Nuclear Research and the U.S. Lawrence Livermore and Oak Ridge national laboratories. Moscovium (Mc) recognizes Moscow and its surrounding area “and honors the ancient Russian land that is the home of the Joint Institute for Nuclear Research,” an IUPAC press release says.
117
Ts
118
Og
Moscovium Tennessine Oganesson
Tennessine (Ts) “is in recognition of the contribution of the Tennessee region, including Oak Ridge National Laboratory, Vanderbilt University, and the University of Tennessee at Knoxville, to superheavy element research, including the production and chemical separation of unique actinide target materials for superheavy element synthesis,” the release also says. Oganesson (Og) honors Russian nuclear physicist Yuri T. Oganessian, who leads the Flerov Laboratory of Nuclear Reactions at the Joint Institute for Nuclear Research. He joins his countrymen Vasili Samarsky-Bykhovets (samarium), Dmitri Mendeleev (mendelevium), and Georgy Flerov (flerovium) in having a namesake element.—JYLLIAN KEMSLEY
CHEMICAL BONDING
Mercury sandwich complex snags fluoride
CREDIT: C&EN (ELEMENTS); VLADIMIR SHUR (STRUCTURE)
Exotic mercury-anion binding in anticrown complex could be a gateway to new chemistry Researchers in Russia have isolated for the first time a mercury anticrown complex binding a fluoride ion. This feat comes decades after chemists first started exploring these unusual compounds. Synthesis of the mercury-fluoride sandwich opens up new possibilities in ion-sensing applications and could lead to new strategies for fluorination reactions. Anticrowns, as the name suggests, are the chemical opposites of crown ethers, which are cyclic polyethers that tightly bind cations and help to form stable salts for catalysis and other applications. Anticrowns are also cyclic compounds, but they tightly bind anions. Chemists are interested in studying mercury anticrowns, along with related boron- and antimony-containing Lewis acid systems, as selective sensors of halide, cyanide, and azide anions, for example to monitor water quality. One of the most studied anticrowns is the trimercury compound
(HgC6F4)3. It tends to form oligomeric assemblies stabilized by “mercurophilic” interactions between mercury atoms in adjacent anticrown units. But until now, researchers had not been able to isolate individual dimers containing fluoride. A team led by Vladimir B. Shur of the Russian Academy of Sciences’ A. N. Nesmeyanov Institute of Organoelement Compounds made the fluoride complex by mixing (HgC6F4)3 with a tetrafluoroborate
= Hg
=F
=C
Mercury anticrown fluoride complex
salt (Organometallics 2016, DOI: 10.1021/ acs.organomet.6b00231). On the basis of spectroscopic studies and the crystal structure, Shur and his colleagues show that a single fluoride is coordinated to the dimer’s six mercury atoms. “This is beautiful work describing a stunning fluoride sandwich structure,” says François P. Gabbaï of Texas A&M University, whose group designs and studies molecular ion-sensing compounds. Gabbaï’s group once caught a fleeting glimpse of the mercury-fluoride sandwich using mass spectrometry: “However, I assumed it would be too unstable to isolate,” he tells C&EN. What makes the complex surprising, Gabbaï explains, is that fluoride is a “hard” nonpolarizable species and mercury is a “soft” polarizable species, which chemists typically don’t expect to attract each other. Besides the “undeniable aesthetic aspects” of the new complex, Gabbaï says it will be interesting to see if the complex could release naked fluoride anions for nucleophilic fluorination reactions.—STEVE RITTER JUNE 13, 2016 | CEN.ACS.ORG | C&EN
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