Abstract
Using backbone modification of popular β-diketiminate ligands, (RDip)nacnac = HC-(RCNDip)(2), with R = Et, iPr (Dip = 2,6-iPr(2)C(6)H(3)), we have prepared the new β-diketiminate gallium-(I) complexes [((EtDip)nacnac)-Ga] 2a and [( (iPrDip)nacnac)-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 [((RDip)nacnac)-Ga-{(C(6)H(5))-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 [((EtDip)nacnac)-Ga-{(C(6)H(4))-N-(H)-NPh}] 5, and reaction with DMSO and benzaldehyde afforded [((EtDip)nacnac)-Ga-(PhNNHPh)-(CH(2)S-(O)-Me)] 6 after DMSO deprotonation and [((EtDip)nacnac)-Ga-(PhNN-(Ph)-CH-(Ph)-O)] 7 from C-N coupling, respectively. Compound 2a also reacted with the aluminum-(III) hydride complexes (NHC)-AlH(3) (NHC = {MeCN-(iPr)}(2)C) and (Me(3)N)-AlH(3) to the Ga-Al-bonded complex [((EtDip)nacnac)-Ga-(H)-Al-(H(2))-(NHC)] 8 and [((EtDip)nacnac)-GaH(2)] 9, respectively. Gallium-(I) complex 2a is a good alternative to commonly used [((MeDip)nacnac)-Ga] (R = Me) for the study and application of low-oxidation-state gallium complexes.