New bis(aryloxy)-Ti(IV) complexes and their use for the selective dimerization of ethylene to 1-butene.

New titanium complexes of general formula [(ArO)(n)Ti(Oi-Pr)((4-n))] were synthesized and used as pre-catalysts for the selective dimerization of ethylene to 1-butene. The complexes were prepared in cyclohexane using [Ti(Oi-Pr)(4)] and one or two equivalents of the corresponding phenols (ArOH) at room temperature. In this work, both monodentate and chelating phenols were evaluated. For alkyl-substituted phenols, it was demonstrated that large steric hindrance at both ortho and ortho' positions selectively yielded the mono-substituted complexes [(ArO)Ti(Oi-Pr)(3)]. Substitution at only one of the ortho positions allowed both the mono- and the di-substituted Ti complexes to be isolated. When a heteroatom was introduced on the phenol backbone, di-substitution systematically occurred except with phenols presenting a hemilabile -CH(2)NR(2) group at the ortho position. Upon activation with 3 equiv. of AlEt(3) at 20 bar and 60 °C, all the complexes selectively dimerized ethylene to 1-butene (>86% of butenes among which 99% of 1-butene). An increase of the steric bulk at the ortho position of the ligand or the introduction of a functional group led to decreased activity compared to [Ti(Oi-Pr)(4)].

[1]  M. Pichler,et al.  Preparation and structures of aryloxy- and alkoxy-Ti(IV) complexes and their evaluation in ethylene oligomerisation and polymerisation. , 2012, Dalton transactions.

[2]  Mathieu J-L Tschan,et al.  New processes for the selective production of 1-octene , 2011 .

[3]  T. Agapie,et al.  Selective ethylene oligomerization: Recent advances in chromium catalysis and mechanistic investigations , 2011 .

[4]  D. McGuinness.  Olefin oligomerization via metallacycles: dimerization, trimerization, tetramerization, and beyond. , 2011, Chemical reviews.

[5]  Xinquan Hu,et al.  Synthesis, characterisation and ethylene oligomerization behaviour of N-(2-substituted-5,6,7-trihydroquinolin-8-ylidene)arylaminonickel dichlorides , 2011 .

[6]  P. Ghosh,et al.  Titanium isopropoxide complexes of a series of sterically demanding aryloxo based [N2O2]2- ligands as precatalysts for ethylene polymerization. , 2010, Dalton transactions.

[7]  Y. Inoue,et al.  Trimerization of Ethylene to 1-Hexene with Titanium Complexes Bearing Phenoxy−Imine Ligands with Pendant Donors Combined with MAO , 2010 .

[8]  John E. Bercaw,et al.  NMR Chemical Shifts of Trace Impurities: Common Laboratory Solvents, Organics, and Gases in Deuterated Solvents Relevant to the Organometallic Chemist , 2010 .

[9]  Wen‐Hua Sun,et al.  Nickel complexes bearing 2-(1H-benzo[d]imidazol-2-yl)-N-benzylidenequinolin-8-amines: Synthesis, structure and catalytic ethylene oligomerization , 2009 .

[10]  H. Olivier-Bourbigou,et al.  Mono(aryloxido)Titanium(IV) Complexes and Their Application in the Selective Dimerization of Ethylene , 2009 .

[11]  Qing Wu,et al.  Syntheses, Structures, and Catalytic Ethylene Oligomerization Behaviors of Bis(phosphanyl)aminenickel(II) Complexes Containing N‐Functionalized Pendant Groups , 2009 .

[12]  A. Spek,et al.  Nickel and palladium complexes of new pyridine-phosphine ligands and their use in ethene oligomerization , 2009 .

[13]  R. F. Jordan,et al.  Ethylene Dimerization by Cationic Palladium(II) Alkyl Complexes that Contain Bis(heterocycle)methane Ligands , 2007 .

[14]  Wen‐Hua Sun,et al.  Synthesis, Characterization, and Ethylene Oligomerization of Nickel Complexes Bearing N-((Pyridin-2-yl)methylene)quinolin-8-amine Derivatives† , 2007 .

[15]  G. Tembe,et al.  Synthesis of ultra‐low‐molecular‐weight polyethylene wax using a bulky Ti(IV) aryloxide–alkyl aluminum catalytic system , 2007 .

[16]  T. Agapie,et al.  Cyclometalated Tantalum Diphenolate Pincer Complexes: Intramolecular C−H/M−CH3 σ-Bond Metathesis May Be Faster than O−H/M−CH3 Protonolysis , 2007 .

[17]  M. Chiang,et al.  Preparations and structures of titanium(IV) complexes containing 8-hydroxyquinolinate and a Schiff-base N-(2-oxyphenyl)salicylideneiminate , 2007 .

[18]  David J. Williams,et al.  Combining hard and soft donors in early-transition-metal olefin polymerization catalysts. , 2006, Inorganic chemistry.

[19]  I. Goldberg,et al.  Group IV complexes of a tetradentate amine mono(phenolate) ligand: a second side-arm donor stabilizes cationic species. , 2005, Inorganic chemistry.

[20]  Shashank Mishra,et al.  Synthesis and spectroscopic characterization of aryloxide derivatives of titanium(IV) and zirconium(IV) , 2005 .

[21]  D. H. Morgan,et al.  Advances in selective ethylene trimerisation – a critical overview , 2004 .

[22]  L. Toupet,et al.  C2-symmetric fluorous diamino-dialkoxide complexes of early transition metals , 2004 .

[23]  V. C. Gibson,et al.  Advances in non-metallocene olefin polymerization catalysis. , 2003, Chemical reviews.

[24]  D. Vogt.  Oligomerization of ethylene to higher linear alpha-olefins , 2002 .

[25]  P. Deckers,et al.  Switching a Catalyst System from Ethene Polymerization to Ethene Trimerization with a Hemilabile Ancillary Ligand. , 2001, Angewandte Chemie.

[26]  Y. Matsumura,et al.  Construction of persistent phenoxyl radical with intramolecular hydrogen bonding. , 2001, Journal of the American Chemical Society.

[27]  M. Boom,et al.  Alkyl− and Aryl−Oxygen Bond Activation in Solution by Rhodium(I), Palladium(II), and Nickel(II). Transition-Metal-Based Selectivity , 1998 .

[28]  K. Wieghardt,et al.  Phenoxyl Radical Complexes of Zinc(II) , 1997 .

[29]  M. Kindermann,et al.  P/O Ligand Systems: Synthesis, Reactivity, and Structure of Tertiaryo-Phosphanylphenol Derivatives , 1996 .