화학공학소재연구정보센터
Inorganic Chemistry, Vol.46, No.9, 3623-3631, 2007
Boron and aluminum complexes of sterically demanding phosphinimines and phosphinimides
Reactions of sterically demanding phosphinimines R3PNH [R = i-Pr (1), t-Bu (2)] were examined. Reactions with B(C6F5)(3) formed the adducts (R3PNH)B(C6F5)(3) [R = i-Pr (3), t-Bu (4)] in high yield. On the other hand, 2 reacts with HB(OBu)(2), evolving H-2 to give t-Bu3PNB(OBu)(2) (5). The reaction of 2 equiv of 2 with BH3 center dot SMe2 affords the species (t-Bu3PN)(2)BH (6). In contrast, the reaction of n-Bu(t-Bu)(2)PNH with BH3 center dot SMe2 results in the formation of the robust adduct n-Bu(t-Bu)(2)PNH center dot BH3 (8). An alternative route to borane-phosphinimide complexes involves Me3SiCl elimination, as exemplified by the reaction of BCl2Ph with n-Bu3PNSiMe3, which gives the product n-Bu3PNBCl(Ph) (9). The corresponding reactions of the parent phosphinimines 1 and 2 with AlH3 center dot NMe2Et give the dimers [(mu-i-Pr3PN)AlH2](2) (10) and [(mu-t-Bu3PN)AlH2](2) (11). Species 11 reacts further with Me3SiO3SCF3 to provide [(mu-t-Bu3PN)AlH(OSO2CF3)](2) (12). The reaction of the lithium salt [t-Bu3PNLi](4) (13) with BCl3 proceeds smoothly to give t-Bu3PNBCl2 (14), which is readily alkylated to give t-Bu3PNBMe2 (15). Subsequent reaction of 15 with B(C6F5)(3) results in methyl abstraction and the formation of [(mu-t-Bu3PN)BMe](2)[MeB(C6F5)(3)](2) (16). The reaction of 13 in a 2:1 ratio with BCl3 gives the salt [(t-Bu3PN)(2)B]Cl (17). This species can be methylated to give (t-Bu3PN)(2)BMe (18), which undergoes subsequent reaction with [Ph3C][X] (X = [B(C6F5)(4)], [PF6]) to form the related salts [(t-Bu3PN)(2)B][B(C6F5)(4)] (19) and [(t-Bu3PN)(2)B][PF6] (20), respectively. Analogous reactions with [Ph3C][BF4] afforded [t-Bu3PNBF2](2) (21). Compounds 3, 4, 6, 8, 11, 12, 17, 19, and 21 were characterized by X-ray crystallography.