Syntheses and Reactions of Derivatives of (Pyrrolylaldiminato)germanium(II) and -Aluminum(III)

(Pyrrolylaldiminato)­germanium­(II) chloride, LGeCl (1), was prepared by reacting LLi (L = 2-(ArNCH)-5-tBuC4H2N; Ar = 2,6-iPr2C6H3) with 1 equiv of GeCl2·(dioxane). Treatment of LGeCl (1) with
KOtBu or LiN­(H)Ar yielded LGeR (R = OtBu (2), N­(H)Ar (3)) by halide metathesis.
(Pyrrolylaldiminato)­methylaluminum chloride, LAlMe­(Cl) (4), was obtained from the reaction of LLi and MeAlCl2 or
by treating LH with Me2AlCl in toluene. Treatment of LH
with Me2AlCl or AlCl3 in Et2O at
−18 °C resulted in the 1:1 adducts LH·AlMe2Cl (5) and LH·AlCl3 (5′),
respectively. Further reaction of 4 with 2 equiv of LiNEt2 led to the insertion of the NEt2 group into the
CN bond together with the elimination of LiCl, to afford L′(NEt2)­AlMe­(NEt2)­Li­(THF) (6). Similarly,
treatment of 4 with 2 equiv of LiPPh2(THF)2 gave L′(PPh2)­AlMe­(OC4H8-PPh2)­Li­(THF)2 (7) accompanied
by ring opening of THF. Single-crystal X-ray structure determinations
revealed that 3 and 4 each contained enantiomeric
pairs, while 6 and 7 each adopted a single
enantiomer.