Synthesis, Structure and Chemistry of Mono- and Digallane Complexes Supported by N,O-Ketimine Ligand
Résumé
A series of N,O-ketimine supported gallium and digallane complexes have been synthesized and structurally characterized. The mono(ketiminate) gallium dichloride [OCMeCHCMeN(Dipp)]GaCl2, 2 (Dipp=2,6-(Pr2C6H3)-Pr-i) and bis(ketiminate) gallium chloride [OCMeCHCMeN(Dipp)](2)GaCl, 3 were isolated from the reaction of GaCl3 with 1 and 2 equivalents of lithiated ketimine, [OCMeCHCMeN(Dipp)]Li, 1 respectively. Treatment of 1 with "GaI'' yielded diiodobis(ketiminate) digallane complex [OCMeCHCMeN-(Dipp)](2)Ga2I2, 4. To the best of our knowledge, compound 4 is the first report on N,O-ketiminate ligand supported stable heteroleptic digallane(II) complex. The frontier molecular orbital analysis and a high Wiberg Bond Index (WBI) values support the strong interaction between the gallium centers in 4. In an attempt to synthesize alkyl substituted Ga complexes, we carried out the reaction of ketimine ligand with (GaBu2Cl)-Bu-t (1:1 ratio) that generated the adduct [OCMeCHCMeN(H)(Dipp)](GaBu2Cl)-Bu-t, 5. In a similar fashion, dialkyl gallium complex [OCMeCHCMeN(Dipp)](GaBu2)-Bu-t, 6 was obtained from the reaction of 1 with (GaBu2Cl)-Bu-t. All the compounds have been charecterized by H-1, (CNMR)-C-13 and mass spectroscopy. The molecular structures of complexes 2-5 have also been determined by single crystal X-ray diffraction analysis.