Tridentate iminopyrrolyl nickel complexes and their use as catalysts for the reaction of polymerisation of ethylene to hyperbranched polyethylene
AssigneeInstituto Superior Tecnico
InventorsPatrícia DA SILVA LOPES, Cláudia Alexandra CARICA FIGUEIRA, Pedro Manuel MACHADO TEIXEIRA GOMES
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Abstract
The present invention relates to the preparation of novel nickel complexes containing iminopyrrolyl-type ligands, having the general molecular structure (I), and to their use as active catalysts in the polymerisation reaction of ethylene to hyperbranched polyethylene. The structure of the ligand precursor is such that it allows the occurrence of a cyclometallation reaction by the activation of a C—H bond, in the coordination reaction to the metal centre, generating a C,N,N′-tridentate complex.
Claims6
Tridentate iminopyrrolyl nickel complexes, wherein the general molecular formula (I), in which the chelating iminopyrrolyl ligand is bonded to the nickel centre in a tridentate fashion, through a subsequent cyclometallation reaction by an intramolecular C—H activation, in which:
- a) Ar represents an aryl group, such as phenyl, biphenyl, naphtyl and equivalents, or a substituted aryl group, especially phenyl, having one or both ortho positions of the aromatic ring substituted with alkyl groups C1-C4, unsubstituted or substituted alkoxy or aryl groups, the latter preferably having alkyl C1 or trifluoromethyl groups in meta positions;
- b) R1 represents a hydrogen atom or an alkyl group C1-C4;
- c) R2 represents a hydrogen atom or an alkyl group C1-C4 or a substituted or unsubstituted aryl group preferably phenyl;
- d) R3 always represents a methylene group;
- e) R4 and R5 represent hydrogen atoms;
- f) R6 represents a hydrogen atom, an alkyl group C1-C11, an unsubstituted or substituted aryl group or a halogen, but preferably a hydrogen atom;
- g) L represents a neutral coordinating ligand, such as triphenylphosphine, tri(C1-C6 alkyl)phosphine, tricycloalkylphosphine, diphenylalkylphosphine, dialkylphenylphosphine, trialkylamine, arylamine such as pyridine, a nitrile such as acetonitrile or equivalent.
Tridentate nickel complexes, wherein the general molecular formula (I), in which the iminopyrrolyl chelating ligand is bonded to the nickel centre in a tridentate fashion, through a subsequent cyclometallation reaction by a C—H intramolecular activation, in which:
- a) Ar represents an aryl group, such as phenyl, biphenyl, naphtyl and equivalents, or a substituted aryl group, especially phenyl, having one or both ortho positions of the aromatic ring substituted with substituted or unsubstituted alkoxy or aryl groups, the latter preferably having C1 alkyl or trifluoromethyl groups, in meta positions;
- b) R1 and R2 represent together a fused aromatic ring in the corresponding C═C bond, preferably a phenyl, substituted at least in one of the ortho positions by a methylene group (R3), but which may be or not substituted in the other positions, by different or equal substituents, that can be C1-C4 (preferably methyl, isopropyl or t-butyl) or trifluoromethyl, methoxy or halogen;
- c) R3 always represents a methylene group;
- d) R4 and R5 represent hydrogen atoms;
- e) R6 represents a hydrogen atom, an alkyl group C1-C11, a substituted or unsubstituted aryl group or a halogen, but preferably a hydrogen atom;
- f) L represents a neutral coordinating ligand, such as triphenylphosphine, tri(C1-C6 alkyl)phosphine, tricycloalkylphosphine, diphenylalkylphosphine, dialkylphenylphosphine, trialkylamine, arylamine such as pyridine, a nitrile such as acetonitrile or equivalent.
Dependencies are inferred from the claim text.