Sc and Y bis(alkyl) complexes supported by bidentate and tridentate amidinate ligands. Synthesis, structure and catalytic activity in polymerization of isoprene and 1-heptene

Abstract

A series of bis(alkyl) complexes {(tBu)C[N(2,6-Me2C6H3)]2}Ln(CH2SiMe3)2(THF)n (Ln = Y, n = 1 (1); Ln = Sc, n = 1 (2)), {2-[Ph2P(O)]C6H4NC(tBu)N(2,6-Me2C6H3)}Sc(CH2SiMe3)2 (3), {2-[Ph2P(NPh)]C6H4NC(tBu)N(2,6-Me2C6H3)}Sc(CH2SiMe3)2 (4) coordinated by bi- (N,N) and tridentate...

Synthesis, Characterization, and Reactivity Studies of New Cyclam-Based Y(III) Complexes

“…11 B NMR was referenced to external BF 3 .Et 2 O (0 ppm). Two-dimensional NMR experiments such as 1 H- 13 C HSQC and 1 H-1 H COSY were performed in order to make all the assignments. Elemental analyses (C, H, N) were performed in a Fisons CHNS/O analyzer Carlo Erba Instruments EA-1108 equipment (Carlo Erba Strumentazione, Milano, Italy) at the Laboratório de Análises do Instituto Superior Técnico.…”

“…The mixture of solutions was frozen with liquid nitrogen and it was degassed under vacuum. The NMR tube was sealed with the system under vacuum and was left to warm up to −80 • C. A variable temperature 1 H NMR experiment was performed and the formation of compound 7 was detected at −30 • C. At this temperature, 13 C{ 1 H} and 2D NMR spectra were performed to confirm the formation of compound 7. The product was extremely unstable and its decomposition was observed in 8 h at −20 [C2]CH 2 N), 1.87 (m, 2H, CH 2 CH 2 CH 2 ), 1.29 (br, 36H, C(CH 3 ) 3 ), −0.92 (s, 9H, Si(CH 3 ) 3 ), −1.29 (d, 2H, 2 J H-H = 10 Hz, YCH 2 SiMe 3 ), −1.37 (d, 2H, 2 J H-H = 10 Hz, YCH 2 SiMe 3 ).…”

“…The product was extremely unstable and its decomposition was observed in 8 h at −20 [C2]CH 2 N), 1.87 (m, 2H, CH 2 CH 2 CH 2 ), 1.29 (br, 36H, C(CH 3 ) 3 ), −0.92 (s, 9H, Si(CH 3 ) 3 ), −1.29 (d, 2H, 2 J H-H = 10 Hz, YCH 2 SiMe 3 ), −1.37 (d, 2H, 2 J H-H = 10 Hz, YCH 2 SiMe 3 ). 13…”

“…The post-metallocene technology in the chemistry of rare-earth metals has been growing at a fast pace to fulfill the requirements of more applicable and suitable catalysts. In this context, yttrium complexes have attracted much attention due to their high reactivity in intramolecular hydroamination [2][3][4][5][6][7][8][9][10] as well as olefin [11][12][13][14] and cyclic ester [15][16][17][18][19][20] polymerization catalysis. The hard Lewis acid nature of yttrium explains its tendency to coordinate to ligands that contain oxygen and nitrogen donors [21][22][23][24][25][26][27][28].…”