Synthesis and reactivity of five-coordinate indium halides and alkyls

New five-coordinate indium halides and alkyls have been prepared which contain the bulky Schiff base ligands, Salen (^tBu) (N, N’-ethylenebis(3,5-di-tert-butylsalicylideneimine), Salpen(^tBu) (N, N’-propylenebis(3,5-di-tert-butylsalicylideneimine)), Salomphen(^tBu) (N, N’-phenylenebis(3,5-di-tert-butylsalicylidene-imine)) and Salomphen(^tBu) (N, N’-(3,4-dimethyl)phenylenebis(3,5-di-tert-butylsalicylideneimine)). These are of formula LInX (where L = Salen(^tBu) X = C1(l), Br (5), Et (9), Me (13); L = Salpen(^tBu), X = C1(2), Br (6), Et(l0), L = Salophen(^tBu), X = C1(3), Br (7), Et (11) and L = Salomphen(^tBu), X = C1(4), Br (8), Et (12). Compared to four-coordinate indium compounds 1-15 are remarkably unreactive with a number of protic and lithiated reagents. Only Salen(^tBu)InOSiPh₃ (14) could be isolated from a rational synthesis. In a related reaction, [Salpen(^tBu)In(µ-OMe)]₂ (15) was isolated in only trace quantities.