Crystalline di- or trianionic metal (Al, Sm) beta-diketiminates

The new [Al(L-Tol)Br-2] (1) and the known [Al(L-Ph)Me-2] (2) were prepared as potential precursors to more novel aluminium compounds. In the event, only the latter was effective. Thus 2 and two equivalents of potassium was the source of [{Al(L-Ph)Me2K2(OEt2)}(2)] (3). The complexes [{KSm(L-Ph)(2)}(2)] (4), [Sm-2(L-Dph)(3)] (5) and [Sm(L-Tol,L-Ad)(L-Tol,L-Ad-H)] (6) were obtained from SmI2 and two equivalents of the appropriate potassium beta-diketiminate [L-Ph or L-Tol or L-Dph = {N(SiMe3)C(Ar)}(2)CH, Ar = Ph or C6H4Me-4 or C6H4Ph-4; L-Tol,L-Ad = N(SiMe3)C(C6H4Me-4)C(H)C(Ad)NSiMe3, L-Tol,L-Ad-H = N(SiMe3)C(C6H4Me-4)C(H)C(Ad)NSiMe2CH2, Ad = 1-adamantyl]. Crystalline complexes 3-6 were isolated in very low (4, 5) or satisfactory (3, 6) yield and characterised by X-ray diffraction. From comparisons of the M-N, N-C, C-C and C-CAr bond lengths with suitable standards, complexes 3-5 are assigned as containing Al3+/(L-Ph)(3-) for 3, Sm3+/(L-Ph)-/(L-Ph)(3-) for 4, and {Sm3+}(2)/(L-Dph)(-)/(L-Dph)(2-)/(L-Dph)(3-) for 5. Complex 6 is best formulated as a Sm3+ compound with one "normal" (L-Tol,L-Ad)(-) and one deprotonated L-Tol,L-Ad-H)(2-) ligand.