Oxygen-Centered Hexatantalum Tetradecaimido Cluster Complexes
- 29 December 2007
- journal article
- research article
- Published by American Chemical Society (ACS) in Inorganic Chemistry
- Vol. 47 (3), 1053-1066
- https://doi.org/10.1021/ic701920v
Abstract
The syntheses and characterization of several octahedral hexatantalum cluster compounds of formula (ArN)14Ta6O are described (Ar = Ph, p-MeC6H4, p-MeOC6H4, p-t-BuC6H4, p-BrC6H4, m-ClC6H4). Treatment of Bn3TaN-t-Bu (Bn = CH2C6H5) or pentakis(dimethylamido)tantalum with an excess of the appropriate aniline and stoichiometric water or tantalum oxide afforded varying yields of arylimido clusters. The structures of two species were confirmed by X-ray diffraction (XRD), while the identity of the central oxygen atom was elucidated by electrospray mass spectrometry (MS) using 17O/18O-enriched material. The title species are very air- and moisture-sensitive but quite thermally stable in solution. Experimentally determined optical properties and oxidation/reduction potentials, as well as some computational results, indicate that they possess an electronic structure wherein the highest occupied molecular orbitals are ligand-centered, while the lowest unoccupied orbitals are metal-centered and delocalized throughout the tantalum cage. Whereas chemical oxidation resulted in cluster decomposition, reduction with decamethylcobaltocene yielded stable salts of formula [Cp*2Co][(ArN)14Ta6O] (Ar = Ph, Ar = p-MeC6H4). Small-molecule reactivity studies on one of these clusters showed that its imido functionalities are moderately reactive toward oxide donors but inert with respect to metallaheterocycle-forming processes. Clean imido/oxo exchange was observed with aldehydes and ketones, leading cleanly to organic imines with no soluble byproducts being observed. This exchange was also observed with a rhenium oxo compound (generating an imidorhenium complex as the only soluble species). All 14 imido groups were transferred in these reactions, and no mixed-ligand cluster intermediates were ever observed.Keywords
This publication has 51 references indexed in Scilit:
- Synthesis and Properties of Oxygen‐Centered Tetradecaimido Hexatantalum ClustersAngewandte Chemie-International Edition, 2006
- Palladium‐Catalyzed Cross‐Coupling Reactions of Amines with Alkenyl Bromides: A New Method for the Synthesis of Enamines and IminesChemistry – A European Journal, 2004
- Anti-Markovnikov Hydroamination of Terminal AlkynesAngewandte Chemie-International Edition, 2002
- Suggested Modifications to a Distillation-Free Solvent Purification SystemJournal of Chemical Education, 2001
- A New Class of Functionalized Polyoxometalates: Synthetic, Structural, Spectroscopic, and Electrochemical Studies of Organoimido Derivatives of [Mo6O19]2-Journal of the American Chemical Society, 2000
- HETERO-ALKOXIDE GROUP (IV) AND (V) NEO-PENTOXIDE COMPOUNDS. SYNTHESES, CHARACTERIZATIONS, AND X-RAY STRUCTURES OF [Zr(μ-OCHMe2)(OCH2CMe3)3(HOCH2CMe3)]2 AND [Ta(μ-OCH2Me)(OCH2CMe3)4]2Journal of Coordination Chemistry, 1999
- A Cationic Imido Complex of Permethyltantalocene: H2 and Carbon−Hydrogen Bond Activation, [2 + 2] Cycloaddition Reactions, and an Unusual Reaction with Carbon Dioxide That Affords Coordinated IsocyanateOrganometallics, 1998
- Cyclopentadienyl and Imide Ligand Transfer from Zirconium to Iridium: Can Early Transition Metal Imido Compounds Be Used as Imide Transfer Reagents?Organometallics, 1998
- Die Kristallstrukturen von K8Ta6O19 · 16H2O und K7NaTa6O19 · 14H2OZeitschrift für anorganische und allgemeine Chemie, 1997
- Stoichiometric and catalytic hydroamination of alkynes and allene by zirconium bisamides Cp2Zr(NHR)2Journal of the American Chemical Society, 1992