Our work in the press
"Borane Compound Turns Off When Sensing Cyanide"
Chemical and Engineering News June 15, 2009 - Volume 87, Number 24 - p 27
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"ACS Inorganic Division Adds U.S. Touch To Dalton Discussions"
Chemical and Engineering News July 28, 2008 - Volume 86, Number 30 - p 60
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"Dalton Crosses the Pond"
Chemical and Engineering News July 28, 2008 - Volume 86, Number 30 - p 59
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"Making the Cover"
Chemical and Engineering News November 6, 2006 - Volume 84, Number 45 - p 24-27
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"Methyl-lined Pores Trap Simple Alkanes"
Chemical and Engineering News October 6, 2006 - Volume 84, Number 40 - p 90
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"Chemistry to the rescue"
Chemistry World
Chem. Sci., 2004, 1, C85
Katharine Sanderson
Chemistry gets a bad press for creating ‘nasty’ molecules, such as chemical warfare agents, or pesticides. However, chemistry not only creates these molecules but also holds the key for ensuring their safe disposal or degradation.
François Gabbaï and Mieock Kim at Texas A&M University, US, are making organometallic catalysts to investigate the breakdown of organophosphorous esters that are routinely used as pesticides. Their latest success has been a palladium metallacycle catalyst that causes the pesticide-type molecules to break down to non-toxic molecules much faster than they would if left alone. Gabbaï has also identified the intermediate products from the reactions, giving more insight into the way the breakdown occurs.
Gabbaï’s catalysts could prove very useful. ‘We expect that such catalysts could be immobilised on solid supports and used in water reservoirs in which they could remediate traces of pesticide. These investigations might also impact on our ability to design catalysts for the destruction of chemical warfare agents,’ he says.
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A bidentate borane as colorimetric fluoride ion sensor
Fluoride August 2004, Vol. 37, No. 3, p. 234
Albert W. Burgstahler
A bright yellow 1,8-diboranaphthalene, formed by reaction of 10-bromo-9-thia-10-boraan-thracene with lithium dimesityl-1,8-naphthalenediborate, has been found to be a highly selective colorimetric bidentate fluoride ion sensor (λmax 363 nm, ε 17,400/mol·cm) with an association constant exceeding 5 x 109/M in tetrahydrofuran. The short distance between the two boron centers allows a single fluoride anion but no other halide anion to be complexed, which occurs with loss of the yellow color. Unlike monofunctional boranes, addition of water does not lead to decomplexation of the fluoride, and therefore this sensor shows promise for development as a highly selective and very sensitive colorimetric reagent for fluoride ion determination. For recovery of the reagent, fluoride is liberated from the complex by treatment with tris-pentafluorophenylborane.
Authors: Solé S, Gabbaï, FP. Correspondence: FP Gabbaï, Department of Chemistry, Texas A&M University, College Station, TX 77843, USA. E-mail: francois@tamu.edu Keywords: Bidentate borane; Colorimetric fluoride ion sensor. Source: Chem Commun 2004;1284-5.
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Diborane loses its color for F–
Chemical and Engineering News June 7, 2004 - Volume 82, Number 23 – p 30
“Science and technology concentrates” section
By taking advantage of the known ability of borane Lewis acids to bind small anions, postdoctoral researcher Stéphane Solé and chemistry professor François P. Gabbaï of Texas A&M University have designed and synthesized a charge-neutral diborane ligand that has a greater affinity for fluoride ion than other borane receptors. The diborane also loses its bright yellow color when it forms the chelate complex shown, making it the first colorimetric diborane fluoride sensor [Chem. Commun., 2004, 1284]. The researchers studied the ligand and the fluoride complex by spectroscopy, X-ray crystallography, and density functional theory calculations, noting shifts in spectral data and boron-fluorine bond formation that coincide with the loss of color. These changes don't occur when the diborane is treated with chloride, bromide, or iodide ions, they note, indicating that fluoride complexation is a function of the small size of the ligand's binding pocket. Fluoride ion sensors are of interest for the study and treatment of osteoporosis, for dental care, and even for detecting fluoride as a by-product of sarin nerve agent, they note.
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Chemistry and Industry 2000, pp 610
“Highlights” section
Timothy Hughbanks
A molecule containing a rare boron-boron one-electron s-bond has been prepared by Hoefelmeyer and Gabbaï (JACS., 2000, 122, published on the web). After synthesising 1,8-bis(diphenylboryl)-naphthalene (7) in a straightforward fashion, reduction afforded a radical anion, (8), for which EPR measurements indicate the unpaired spin density is equally distributed over both boron centres (see figure 2). To date, only the structure of (7) is available, but a molecular orbital study shows that the LUMO of (7) (and the SOMO of 8) has the expected s-bonding character. The small magnitude of the 11B hyperfine coupling splitting shows the 'half-order bond' is relatively weak and long, and has predominantly boron p-character.
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Chemical and Engineering News Sept. 4, 2000, Volume 78, Number 36, p.13
"NEWS OF THE WEEK" section
Ron Dagani
"Benzene has been sandwiched between two identical planar trimetallic molecules in such a way that each of the six metal atoms coordinates to a different C-C bond of the benzene [J. Amer. Soc., 122, 8335 (2000)]. The interaction represents a new bonding mode for benzene, according to assistant professor of chemistry François P. Gabbaï and visiting scholar Mitsukimi Tsunoda at Texas A&M University. Tsunoda prepared the "supramolecule" by dissolving in boiling benzene a known Lewis acid--trimeric (tetrafluoro-o-phenylene)mercury (shown in both red and blue, above left). The crystals that formed upon cooling were found by X-ray crystallography to consist of extended stacks of organomercury molecules, with each molecular pair sandwiching a single benzene molecule, as shown here in two views. The side view (right) shows a portion of a stack, with carbon depicted in gray; fluorine, greenish-yellow; and mercury, puple. Hydrogen atoms are not shown. In the view from above (left), the organomercury molecules are seen to be arranged in a staggered conformation, making hexacoordination to mercury possible. Because of the stacked structure, each mercury atom coordinates to a C-C bond of two different benzene molecules. Gabbaï's group is investigating whether this new bonding motif could be used to orient a trio of alkyne molecules for cyclization."
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Science Magazine 1 September 2000 Vol 289, Issue 5484, 1433
"EDITORS’CHOICE" section
Phil D. Szuromi
Electron-rich species such as benzene can interact with low-lying unoccupied orbitals of metal centers, for instance, when benzene adsorbs on metal surfaces. Mercury cations and organomercurials are known to have high affinity for arenes. Tsunoda and Gabbai have modeled such surface interactions with the compound 1, which contains three mercury atoms bridged by fluorophenylene groups. Boiling 1 in benzene yields a supramolecular complex whose crystal structure reveals stacks of benzene molecules alternating with 1 in staggered fashion. Each mercury atom interacts with a p bond of benzene in an "h2" fashion (an orbital from the mercury atom points into a p bond). The interaction is highly symmetrical in that the benzene molecules are undistorted; it is also weak, in that the C-C bond lengths in benzene remain unchanged.
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Chemistry and Industry 1998, pp 936-937
“Highlights” section
Timothy Hughbanks
In an effort to increase the Lewis acidity of indium centres in diindacycles, Gabbaï and co-workers (Inorg. Chem., 1998, 37, 5097) have prepared perfluorinated derivatives by the route outlined in Scheme 1. An attempt to prepare the perfluorinated diindacycle from perfluoro-o-phenylenemercury in THF results in disproportionation of the In(I) halide (Cl or Br) into In(0) and InX3, so the initial step is performed in refluxing toluene (top right, Scheme 1). Alternatively, 1,2-bis(halomercurio)tetrafluorobenzene can be reacted with two equivalents of the corresponding indium (I) halide - for which the mechanism in the second line of Scheme 1 is offered. The enhanced Lewis acidity of these perfluorinated derivatives is manifest in the marked shortening of In-O bonds to the THF ligands (by ca 0.09 Å) on moving from the hydrogenated parent compounds to the perfluorinated analogues.
