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The cationic tantalum complex {[η6-Ar-CMe2-η5-C5H4]TaPr}[B(C6F5)4] (1; Ar = 3,5-Me2C6H3) serves as a starting materialfor a series of neutral, monocationic, and dicationic derivatives.The cationic hydride {[η6-Ar-CMe2-η5-C5H4]TaH}[B(C6F5)4] (2) that results from hydrogenolysisof 1inserts the di- and trisubstituted olefins cyclopenteneand 2-methyl-2-pentene; it reacts with styrene to give the 2,1-insertionproduct, for which the Ta–CH(Me)Ph group is bound in a σ3-allylic fashion. A neutral complex is obtained from 1by reaction with Br–, and a dicationicderivative is available by hydride abstraction from 2using the Lewis acidic trityl cation. All compounds described hereretain the unusual ansa-(η5-cyclopentadienyl,η6-arene) coordination mode of the ligand that stabilizes theformally Ta(III) center. X-ray structures and DFT calculations showthat the metal–arene interaction contains a significant πback-donation component (arene←Ta(III)) that differs only slightlyin the series, despite the variation of charge at the metal center. [ABSTRACT FROM AUTHOR]