A base-free terminal thorium phosphinidene metallocene and its reactivity toward selected organic molecules

The stable base-free terminal phosphinidene thorium metallocene, [(5)-1,2,4-(Me3C)(3)C5H2](2)Th?P-2,4,6-(Bu3C6H2)-Bu-t (2), can be isolated from the reaction of the thorium dichloride complex [(5)-1,2,4-(Me3C)(3)C5H2](2)ThCl2 (1) with 2 equiv. of 2,4,6-(Me3C)(3)C6H2PHK in THF. The reactivity of 2 in the activation of various small organic molecules such as diselenides, phosphines, imines, ketones, phosphine oxides, thiazole, imidazole derivatives and amines was explored. For example, when complex 2 is treated with Ph2Se2, the phosphinidene is replaced, yielding diselenido compound [(5)-1,2,4-(Me3C)(3)C5H2](2)Th(SePh)(2) (3). Moreover, E-H (E = P, N, C) bond activation occurs on exposure of 2 to 2,4,6-(Pr3C6H2PH2)-Pr-i, PhPH2, (p-tolyl)(2)C?NH, 1-indanone, cyclohexanone, Me3PO, thiazole, 1-methylimidazole and p-toluidine, resulting in the phosphido complex [(5)-1,2,4-(Me3C)(3)C5H2][(5),-C-1,2-(Me3C)(2)-4-(CH2CMe2)C5H2]Th(PH-2,4,6-(Pr3C6H2)-Pr-i) (4), the metallaheterocycle [(5)-1,2,4-(Me3C)(3)C5H2](2)Th((2)-P2Ph2) (5), the iminato phosphido complex [(5)-1,2,4-(Me3C)(3)C5H2](2)Th(PH-2,4,6-(Bu3C6H2)-Bu-t)[N?C(p-tolyl)(2)] (6), the phosphido enolyl compound [(5)-1,2,4-(Me3C)(3)C5H2](2)Th(PH-2,4,6-(Bu3C6H2)-Bu-t)(-O-1-OC9H7) (7), the enolyl complex [(5)-1,2,4-(Me3C)(3)C5H2][(5),-C-1,2-(Me3C)(2)-4-(CH2CMe2)C5H2]Th(-O-1-OC6H9) (8), the alkyl complex [(5)-1,2,4-(Me3C)(3)C5H2][(5),-C-1,2-(Me3C)(2)-4-(CH2CMe2)C5H2]Th(-O,C-OPMe2CH2) (9), the phosphido thiazolyl complex [(5)-1,2,4-(Me3C)(3)C5H2](2)Th(PH-2,4,6-(Bu3C6H2)-Bu-t)(C3H2NS) (10), the bis-imidazolyl complex [(5)-1,2,4-(Me3C)(3)C5H2](2)Th[2-(1-MeC3H2N2)](2) (11), and the imido complex [(5)-1,2,4-(Me3C)(3)C5H2](2)Th?N(p-tolyl) (12), respectively. Several spectroscopic techniques were employed for the characterisation of the new complexes 3-11, and in addition the solid-state molecular structures of compounds 3-6, 8-9 and 11 were further confirmed by X-ray diffraction analyses.