American Chemical Society
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Tantalum Complexes Supported by Asymmetric [ONO] Ligands. The Role of Weakly Coordinating Anions on Their Reactivity

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posted on 2012-03-12, 00:00 authored by Rosa Fandos, Antonio Otero, Ana M. Rodríguez, Sara Suizo
The tantalum complex [TaCp*Me2(OOCPhNCHPhO-κ3O,N,O)] (2) has been synthesized by reaction of [TaCp*Me4] (Cp* = η5-C5Me5) with 2-(salicylideneamino)­benzoic acid. Complex 2 reacts with HOTf to yield the new tantalum derivative [TaCp*Me­(OTf)­(OOCPhNCHPhO-κ3O,N,O)] (3). Moreover, compound 3 reacts with tBuNC or xylylNC to yield the iminoacyl-containing complexes [TaCp*­(C­(Me)NR-κ2C,N)­(OTf)­(OOCPhNCH]­PhO-κ3O,N,O)] (R = tBu (4), 2,6-Me2C6H3 (5)). Compound 4 reacts with water to render the corresponding aqua adduct [TaCp*­(C­(Me)NtBu-κ2C,N)­(H2O)­(OOCPhNCHPhO-κ3O,N,O)]­OTf (6). The reaction of 2 with B­(C6F5)3 in a 1:1 molar ratio yields the corresponding carboxylate adduct [TaCp*Me2(OOCPhNCHPhO·B­(C6F5)33O,N,O)] (7). The reaction of compound 2 with H­[BF4] gives the BF3 adduct [TaCp*FMe­(OOCPhNCHPhO.BF33O,N,O)] (8). Compound 8 decomposes in CH2Cl2 at room temperature to render [BF­(OOCPhNCHPhO-κ3O,N,O)] (9). The molecular structures of complexes 2, 3, 6, and 9 have been established by X-ray diffraction methods.