Using backbone modification of popular β-diketiminate ligands, RDipnacnac = HC (RCNDip) 2, with R = Et, iPr (Dip = 2, 6-iPr2C6H3), we have prepared the new β-diketiminate gallium (I) complexes (EtDipnacnac) Ga 2a and (iPrDipnacnac) Ga 2b by salt metathesis/reduction using “GaI” in moderate to good (68%, 2a) and poor (10%, 2b) isolated yields, respectively, highlighting the influence of the ligand backbone substitution on the reaction success. The gallium (I) complexes were converted with azobenzene to the gallium (III) complexes (RDipnacnac) Ga (C6H5) NNPh 4a (R = Et) and 4b (R = iPr) with reduced former azobenzene fragments showing an N, ortho-C (H) -chelating coordination to the Ga centers. Complex 4a was further converted to its C–H-activated tautomer (EtDipnacnac) Ga (C6H4) N (H) NPh 5, and reaction with DMSO and benzaldehyde afforded (EtDipnacnac) Ga (PhNNHPh) (CH2S (O) Me) 6 after DMSO deprotonation and (EtDipnacnac) Ga (PhNN (Ph) CH (Ph) O) 7 from C–N coupling, respectively. Compound 2a also reacted with the aluminum (III) hydride complexes (NHC) AlH3 (NHC = MeCN (iPr) 2C) and (Me3N) AlH3 to the Ga–Al-bonded complex (EtDipnacnac) Ga (H) –Al (H2) (NHC) 8 and (EtDipnacnac) GaH2 9, respectively. Gallium (I) complex 2a is a good alternative to commonly used (MeDipnacnac) Ga (R = Me) for the study and application of low-oxidation-state gallium complexes.
Dong et al. (Wed,) studied this question.