A new stable intermediary mode between η3-2-aminoallyl complexes and metallacyclobutanimines. Synthesis and structural characteristic of η3-azatrimethylenemethane and N-protonated, N-alkylated, N-arylated η3-azatrimethylenemethane complexes of Pt and Pd

Abstract Regioselective addition of ammonia, primary or secondary amines, aniline, or amino derivatives either to a neutral ( η 1 -allenyl)platinum complex trans -Pt(Br)(PPh 3 ) 2 ( η 1 -CHCCH 2 ) ( 1 ) or to a cationic η 3 -allenyl/propargyl platinum complex [Pt(PPh 3 ) 2 ( η 3 -C 3 H 3 )](BF 4 ) ( 2 ) provide the synthesis of cationic N -protonated, N -alkylated, and N -arylated η 3 -azatrimethylenemethane complexes {Pt(PPh 3 ) 2 ( η 3 -CH 2 C(NRR′)CH 2 ]}(X) (R=H R′=H ( 3a ), Me ( 3b ), Et ( 3c ), i Pr ( 3d ), t Bu ( 3e ), c-C 6 H 11 ( 3f ), Ph ( 3g ), CH 2 CH 2 OH ( 3h ), R=R′=Et ( 3i ), c-C 3 H 6 (from azetidine 3j ), Ph ( 3k ), R=Me R′=Ph ( 3l ); X=Br, BF 4 ), respectively. Addition of amides to 1 gave a neutral η 3 -azatrimethylenemethane complex Pt(PPh 3 ) 2 [ η 3 -CH 2 C(NSO 2 Ph)CH 2 ] ( 4m ). Similar reactions using palladium complexes yield {Pd(PPh 3 ) 2 [ η 3 -CH 2 C(NRR′)CH 2 ]}(X) (R=H R′= i Pr ( 7d ), Ph ( 7g ), R=R′=Et ( 7i ); X=Br, BF 4 , OTf), Pd(Br)(PPh 3 )[ η 3 -CH 2 C(NEt 2 )CH 2 ] ( 8i ) and Pd(PPh 3 ) 2 [ η 3 -CH 2 C(NR)CH 2 ] (R=SO 2 Ph ( 9m ), p -SO 2 C 6 H 4 Me ( 9n )). Synthesis of three complexes, {M(PPh 3 ) 2 [ η 3 -CH 2 C(NHR)CH 2 ]} + (M=Pt R=SO 2 Ph ( 3m ); M=Pd R=SO 2 Ph ( 7m ), p -SO 2 C 6 H 4 Me ( 7n )), can not be done by hydroamination reactions, but has been successful using protonation of η 3 - N -TMM complexes 4m , 9m , and 9n , respectively. Spectroscopic and crystallographic characterizations indicate that these N -TMM complexes exhibit intermediary structural features between η 3 -2-aminoallyl and metallacyclobutanimine complexes. 2