Synthesis and characterization of tridentate phenoxy‐imine ligand [N,N,O] nickel(II) and palladium(II) complexes and their catalytic behaviors in vinyl polymerization of norbornene

Abstract

In this study, new complexes LNiCl(1), LNiBr(2), LNiI(3), and LPdCl(4) (L ¼ 4,6-di-tert-butyl-2-(N-(quinolin-8-yl)iminomethyl)phenolato) have been synthesized and characterized. X-ray diffraction studies on Complexes 1 and 4 revealed that N, N, O, and halogen atoms coordinated to metal, with a nearly square planar geometries in all cases. All these complexes are robust and exhibit high activities for the addition polymerization of norbornene (NB) with methylaluminoxane as cocatalyst [up to 47.62 kg PNB(mmol of Ni)and also lead to various activities and molecular weights of polynorbornenes under different reaction conditions. It is noteworthy that Complexes 1 and 4 show better activity under higher reaction temperature of 80 C. However, Complex 2 showed lower activity, and Complex 3 was found nearly inert toward NB polymerization, probably, because of thermal instability.

Rational Design of Sterically Hindered and Unsymmetrical NpyNimOph Pincer‐Type Ligands and Their Palladium(II) Complexes: Catalytic Applications in Suzuki–Miyaura Reaction and Allylation of Aldehydes

“…Pd1‐N3 bond distance 1.936(10) Å and Pd01—N9 1.992(4) Å for complexes 1 and 3 are similar to the reported values however smaller than reported by Bhattacharya and co‐workers and Pd1‐Cl1 bond lengths are in the range of 2.325(4) Å for complex 1 and Pd01—Cl9 is 2.321(2) Å for complex 3 good agreement as reported earlier however longer to previously reported values . Pd1—O1 distance 1.946(9) Å for complex 1 and Pd01—O3 1.959(6) Å for complex 3 longer than reported values …”

“…At present pincer type palladium(II) complexes with a different type of donor atoms are widely utilized as a catalyst for coupling reactions. Few groups are working with tridentate meridional N py N im O ph type ligands and their palladium complexes (shown in Scheme ) . Investigation of literature clearly expressed that such type of complexes is efficient as catalyst for vinyl polymerization of norbornene, carbon‐chlorine coupling reaction as well as SMC reaction.…”

Synthesis and characterization of Ni (II) complexes supported by phenoxy/naphthoxy‐imine ligands with pendant N‐ and O‐donor groups and their use in ethylene oligomerization

“…This complex adopts a nearly square planar geometry around the metal center with Br and N(2) occupying the trans positions (Br‐Ni‐N(2) = 177.63(14)°, O‐Ni‐N(1): 177.00(19)°). The Ni–O and Ni‐N(2) bond distances [1.8715(4) Å, 1.8585(14) Å, respectively] are close to the values previously reported for Ni(II) complexes having phenoxy‐imine ligands …”

A new class of MPV type reduction in group 4 alkoxide complexes of salicylaldiminato ligands: Efficient catalysts for the ROP of lactides, epoxides and polymerization of ethylene

“…The two salicylaldiminato ligands employed in this study were synthesized by the reported methodology employing the condensation of 8-aminoquinoline with 3,5-di-tertbutylsalicylaldehyde giving L1H [L1 = 3,5-t Bu 2 -2-(O)-C 6 H 2 CH=N-8-C 9 H 6 N] and 8-aminoquinoline with 3,5-dichloro-salicylaldehyde yielding L2H [L2 = 3,5-Cl 2 -2-(O)-C 6 H 2 CH=N-8-C 9 H 6 N] respectively in high yields and purities [128].…”

“…Chemical shifts for 1 H and 13 namely rac-LA and L-LA were purchased from Sigma-Aldrich and purified by sublimation under argon atmosphere and stored in glove box. Ligands L1H and L2H were prepared according to literature reported procedures [128]. MAO was purchased from Aldrich.…”