Formation and reactivity of five-coordinate gallium supported by salen ligands

This work is an exploration into the synthesis and reactivity of five-coordinate gallium complexes of the ligands, Salen-(tBu)H₂ [N,N′-ethylenebis(3,5-di-tert-butylsalicyhdeneimine), (1)], Salpen(tBu)H₂ [N,N′-propylenebis(3,5-di-tert-butylsalicylideneimine), (2)], Salophen(tBu)H₂ [N,N′-phenylenebis(3,5-di-tert-butylsalicylideneimine), (3)], and Salomphen(tBu)H₂ [N,N′-(4,5-dimethyl)phenylenebis(3,5-di-tert-butylsalicylideneimine), (4)]. Fully characterized examples include those of general formula LGaX, where L = 1, X = Cl (5), Et (6); 3, X = Cl (7), Et (10); 4, X = Cl (8), Me (9) Et (11). X-ray structural data is presented for 6, 7, 9, 10, and 11. The ability of these complexes to undergo either alkane or salt elimination reactions is described. In one reaction the unusual salt: [{Salophen(tBu)Ga(MeOH)}₂]⁺BPh₄^- (12) is obtained.