Acetamidine complexes as catalysts for ethylene polymerization

Nickel pre-catalysts bearing [(N)-imidoylamidine] ligands; influence of the presence of pyridine and pentafluorophenyl groups in ligand backbone on the reactivity in ethylene polymerizations

“…A pure white powder was obtained after crystallization from ethanol, the 1 H, 13 The ORTEP structure of compound 2Ls (Fig. 3), shows that in the solid state the ligand adopts a non-planar arrangement similar to the previously reported 2,6-MeC 6 H 3 N(C(Me)NC 6 H 3 -2,6-i-Pr) 2 [13].…”

“…1) [13]. As expected, the polymerization reaction shows an increase in molecular weight with increasing pseudo-axial bulk around the nickel center, however, the reactivity was moderate.…”

“…5) two of the nitrogen atoms, N(1) and N(2) occupy a common plane with C(7), C(9) and C(8) while the third, N(3), is slightly twisted out of this plane, more similar to 2,6-MeC 6 H 3 N(C(Me)NC 6 H 3 -2,6-i-Pr) 2 [13] than the 2Ls isomer. The distances between the atoms N(1)eC (7) and N(3)eC(9) are 1.285(2) Å and 1.264(2) Å, which are consistent with a double bond and the distances between N(2)eC (7) and N(2)eC(9) are 1.383(2) Å and 1.437(2) Å which are consistent with a single bond (Table 1).…”

Co(II), Ni(II) and Cu(II) complexes of sterically encumbered N-arylimidoylamidine based [N,N′] chelating ligands

“…The reaction proceeds via an amidine intermediate, which has been well characterized in similar moieties reported earlier [20]. Ligand L 1 has been characterized by 1 H and 13 C NMR, IR, mass spectrometry, and elemental analysis.…”

“…The first mononuclear complex based on imidoyl amidine ligand, [PhNCHN(Ph)CHNPh]CoCl 2 , was reported by Cotton and co-workers [16] [18] and Wilkinson and co-workers prepared the iridium complexes (C 5 Me 5 )Ir[N(2,6-Me 2 C 6 H 3 )CHNRCNC 6 H 3 (Me)CH 2 ] (R = tBu or 2,6-iPr 2 C 6 H 3 ) by the reaction of (C 5 Me 5 )IrNR with 2,6-Me 2 C 6 H 3 NC [19]. Recently, Rojas and co-workers reported on the synthesis of Ni(II) complexes, [2,6-Me 2 C 6 H 3 N{C(Me)N(2, 6-Me 2 C 6 H 3 )} 2 ]NiBr 2 and symmetrical [2,6-Me 2 C 6 H 3 N{C(Me)N-(2,6-iPr 2 C 6 H 3 )} 2 ]NiBr 2 and unsymmetrical [2,6-Me 2 C 6 H 3 NC(Me)N-(2,6-iPr 2 C 6 H 3 )C(Me)N(2,6-iPr 2 C 6 H 3 )]NiBr 2 [20]. These Ni(II) complexes have also been useful in olefin polymerization.…”