Synthesis, structures, and ethylene oligomerization activity of bis(phosphanylamine)pyridine chromium/aluminate complexes

Ahmed Alzamly; Sandro Gambarotta; Ilia Korobkov

doi:10.1021/om4008289

Synthesis, structures, and ethylene oligomerization activity of bis(phosphanylamine)pyridine chromium/aluminate complexes

Ahmed Alzamly, Sandro Gambarotta, Ilia Korobkov

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26 Citations (Scopus)

Abstract

A trivalent chromium complex of a PN(pyridine) ligand system, {[(2,6-Ph₂P-NH)₂C₅H₃N]CrCl ₃}(THF)₂ (1), was prepared and tested as a catalyst for ethylene oligomerization and polymerization, with the purpose of probing the ability of a pyridine ring substituent as a stabilizing factor on catalytically active intermediates. Its nonselective catalytic behavior indicated that ready reduction of the metal center to the divalent state occurred during the activation process. To substantiate this point, we have reacted 1 with a few common aluminate activators and isolated both the divalent complexes {[2,6-Ph₂PNHC₅H₃NAlClEt₂NPPh ₂]Cr(μ-Cl)₂AlEt₂}(toluene) (3) and {[2,6-Ph₂PNHC₅H₃NAlCl-i-Bu₂NPPh ₂]Cr(μ-Cl)₂Al-i-Bu₂}₂ (toluene) (4) and the trivalent complexes {[2,6-Ph₂PNHC₅H ₃NAlClMe₂NPPh₂]CrMe(μ-Cl) ₂AlMe₂}(toluene)_1.5 (2) and {[2,6-Ph ₂PNHC₅H₃ NHNPPh₂]CrEt(μ-Cl) ₂AlEt₂}AlEtCl₃(hexane)_0.5 (5). The reaction of the ligand with the divalent chromium precursor CrCl ₂(THF)₂ in the presence of alkylaluminum afforded {[2,6-Ph₂PNHC₅H₃NCl₂EtAlNPPh ₂]Cr(μ-Cl)₂AlEt₂}₂(toluene) (6) containing aluminate residues, where the metal has preserved the initial divalent state. All of these species showed moderate to high activities toward ethylene oligomerization.

Original language	English
Pages (from-to)	7107-7115
Number of pages	9
Journal	Organometallics
Volume	32
Issue number	23
DOIs	https://doi.org/10.1021/om4008289
Publication status	Published - Dec 9 2013
Externally published	Yes

ASJC Scopus subject areas

Physical and Theoretical Chemistry
Organic Chemistry
Inorganic Chemistry

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@article{902d723d7054467f89e60c34d0ecbd55,

title = "Synthesis, structures, and ethylene oligomerization activity of bis(phosphanylamine)pyridine chromium/aluminate complexes",

abstract = "A trivalent chromium complex of a PN(pyridine) ligand system, {[(2,6-Ph2P-NH)2C5H3N]CrCl 3}(THF)2 (1), was prepared and tested as a catalyst for ethylene oligomerization and polymerization, with the purpose of probing the ability of a pyridine ring substituent as a stabilizing factor on catalytically active intermediates. Its nonselective catalytic behavior indicated that ready reduction of the metal center to the divalent state occurred during the activation process. To substantiate this point, we have reacted 1 with a few common aluminate activators and isolated both the divalent complexes {[2,6-Ph2PNHC5H3NAlClEt2NPPh 2]Cr(μ-Cl)2AlEt2}(toluene) (3) and {[2,6-Ph2PNHC5H3NAlCl-i-Bu2NPPh 2]Cr(μ-Cl)2Al-i-Bu2}2 (toluene) (4) and the trivalent complexes {[2,6-Ph2PNHC5H 3NAlClMe2NPPh2]CrMe(μ-Cl) 2AlMe2}(toluene)1.5 (2) and {[2,6-Ph 2PNHC5H3 NHNPPh2]CrEt(μ-Cl) 2AlEt2}AlEtCl3(hexane)0.5 (5). The reaction of the ligand with the divalent chromium precursor CrCl 2(THF)2 in the presence of alkylaluminum afforded {[2,6-Ph2PNHC5H3NCl2EtAlNPPh 2]Cr(μ-Cl)2AlEt2}2(toluene) (6) containing aluminate residues, where the metal has preserved the initial divalent state. All of these species showed moderate to high activities toward ethylene oligomerization.",

author = "Ahmed Alzamly and Sandro Gambarotta and Ilia Korobkov",

year = "2013",

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doi = "10.1021/om4008289",

language = "English",

volume = "32",

pages = "7107--7115",

journal = "Organometallics",

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TY - JOUR

T1 - Synthesis, structures, and ethylene oligomerization activity of bis(phosphanylamine)pyridine chromium/aluminate complexes

AU - Alzamly, Ahmed

AU - Gambarotta, Sandro

AU - Korobkov, Ilia

PY - 2013/12/9

Y1 - 2013/12/9

N2 - A trivalent chromium complex of a PN(pyridine) ligand system, {[(2,6-Ph2P-NH)2C5H3N]CrCl 3}(THF)2 (1), was prepared and tested as a catalyst for ethylene oligomerization and polymerization, with the purpose of probing the ability of a pyridine ring substituent as a stabilizing factor on catalytically active intermediates. Its nonselective catalytic behavior indicated that ready reduction of the metal center to the divalent state occurred during the activation process. To substantiate this point, we have reacted 1 with a few common aluminate activators and isolated both the divalent complexes {[2,6-Ph2PNHC5H3NAlClEt2NPPh 2]Cr(μ-Cl)2AlEt2}(toluene) (3) and {[2,6-Ph2PNHC5H3NAlCl-i-Bu2NPPh 2]Cr(μ-Cl)2Al-i-Bu2}2 (toluene) (4) and the trivalent complexes {[2,6-Ph2PNHC5H 3NAlClMe2NPPh2]CrMe(μ-Cl) 2AlMe2}(toluene)1.5 (2) and {[2,6-Ph 2PNHC5H3 NHNPPh2]CrEt(μ-Cl) 2AlEt2}AlEtCl3(hexane)0.5 (5). The reaction of the ligand with the divalent chromium precursor CrCl 2(THF)2 in the presence of alkylaluminum afforded {[2,6-Ph2PNHC5H3NCl2EtAlNPPh 2]Cr(μ-Cl)2AlEt2}2(toluene) (6) containing aluminate residues, where the metal has preserved the initial divalent state. All of these species showed moderate to high activities toward ethylene oligomerization.

AB - A trivalent chromium complex of a PN(pyridine) ligand system, {[(2,6-Ph2P-NH)2C5H3N]CrCl 3}(THF)2 (1), was prepared and tested as a catalyst for ethylene oligomerization and polymerization, with the purpose of probing the ability of a pyridine ring substituent as a stabilizing factor on catalytically active intermediates. Its nonselective catalytic behavior indicated that ready reduction of the metal center to the divalent state occurred during the activation process. To substantiate this point, we have reacted 1 with a few common aluminate activators and isolated both the divalent complexes {[2,6-Ph2PNHC5H3NAlClEt2NPPh 2]Cr(μ-Cl)2AlEt2}(toluene) (3) and {[2,6-Ph2PNHC5H3NAlCl-i-Bu2NPPh 2]Cr(μ-Cl)2Al-i-Bu2}2 (toluene) (4) and the trivalent complexes {[2,6-Ph2PNHC5H 3NAlClMe2NPPh2]CrMe(μ-Cl) 2AlMe2}(toluene)1.5 (2) and {[2,6-Ph 2PNHC5H3 NHNPPh2]CrEt(μ-Cl) 2AlEt2}AlEtCl3(hexane)0.5 (5). The reaction of the ligand with the divalent chromium precursor CrCl 2(THF)2 in the presence of alkylaluminum afforded {[2,6-Ph2PNHC5H3NCl2EtAlNPPh 2]Cr(μ-Cl)2AlEt2}2(toluene) (6) containing aluminate residues, where the metal has preserved the initial divalent state. All of these species showed moderate to high activities toward ethylene oligomerization.

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DO - 10.1021/om4008289

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AN - SCOPUS:84890342552

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JF - Organometallics

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ER -

Synthesis, structures, and ethylene oligomerization activity of bis(phosphanylamine)pyridine chromium/aluminate complexes

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