Intrinsic Reactivity of [η⁵-1,3-(Me₃C)₂C₅H₃]₂Th(bipy) toward Small Molecules

The reactivity of the thorium bipyridyl metallocene (Cp2tBu)2Th(bipy) (1; Cp2tBu = η5-1,3-(Me3C)2C5H3) toward a series of small molecules was explored, and the emerging reactivity pattern can be categorized: (1) It may act as a synthon for (Cp2tBu)2Th(II) in contact with alkynes, diazabutadienes, ketazine (Ph2C═N)2, o-benzoquinone, carbodiimides, organic azides, isothiocyanates, elemental sulfur (S8) and selenium (Se), and Ph2S2. (2) It participates in C–C coupling reactions with ketones Ph2CO, (CH2)5CO, and 1-indanone, aldehydes p-MePhCHO and p-ClPhCHO, amidate PhCONH(p-tolyl), seleno-ketone (p-MeOPh)2CSe, imines PhCH═NPh and (p-tolyl)2C═NH, ketazine (PhCH═N)2, and nitriles PhCN, Me3CCN, C6H11CN and CH3CN, to form (Cp2tBu)2Th[(bipy)(Ph2CO)] (15), (Cp2tBu)2Th[(bipy)((CH2)5CO)] (16), (Cp2tBu)2Th[(bipy)(1-(C8H8)CO)] (17), (Cp2tBu)2Th[(bipy)(p-MePhCHO)] (18), (Cp2tBu)2Th[(bipy)(p-ClPhCHO)] (19), (Cp2tBu)2Th[(bipy){PhCONH(p-tolyl)}] (20), (Cp2tBu)2Th[(bipy){(p-MeOPh)2CSe}] (21), (Cp2tBu)2Th[(bipy)(PhCHNPh)] (22), (Cp2tBu)2Th[(bipy){(p-tolyl)2CNH}] (23), (Cp2tBu)2Th[(bipy)(PhCHNN═CHPh)] (24), (Cp2tBu)2Th[(bipy)(PhCN)] (25), (Cp2tBu)2Th[(bipy)(Me3CCN)] (26), (Cp2tBu)2Th[(bipy)(C6H11CN)] (27), and (Cp2tBu)2Th[(bipy)(CH3CN)] (28), respectively. However, in the presence of benzyl nitrile PhCH2CN, the dimeric bis-amido complex {(Cp2tBu)2Th[NHC(CH2Ph)C(Ph)C(C(Ph)CN)NH]}2 (29) is isolated. (3) Isonitriles such as Me3CNC, Me3SiNC, and C6H11NC undergo C–N bond cleavage and C–C coupling to furnish the thorium isocyanido amido complexes (Cp2tBu)2Th[4-(Me3C)bipy](NC) (30), (Cp2tBu)2Th[4-(Me3Si)bipy](NC) (31), and (Cp2tBu)2Th[4-(C6H11)bipy](NC) (32), respectively. A comparison with related thorium bipyridyl metallocene derivatives shows that minor alternations in the supporting cyclopentadienyl ligands modulate the reactivity of these compounds.