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

Article abstract of DOI:10.1039/c2dt30991b

New titanium complexes of general formula [(ArO)_nTi(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 -CH₂NR₂ group at the ortho position. Upon activation with 3 equiv. of AlEt₃ 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].

Full text of DOI:10.1039/c2dt30991b

Electronic Supplementary Material (ESI) for Dalton Transactions
This journal is © The Royal Society of Chemistry 2012
S-1
Supporting Information for DT-ART-05-2012-030991
New bis(aryloxy)-Ti(IV) Complexes and Their Use for the Selective Dimerization of
Ethylene to 1-Butene
Fabien Grasset,a Jean-Benoît Cazaux,a Lionel Magna,*a Pierre Braunsteinb and Hélène
Oliver-Bourbigoua
a
IFPEnergies nouvelles Lyon, Rond point de l’échangeur de Solaize, BP3, 69360 Solaize, France.
Fax: (+33) 4 37 70 20 66; Tel: (+33) 4 37 70 28 86; E-mail: lionel.magna@ifpen.fr
b
Laboratoire de Chimie de Coordination, Institut de Chimie (UMR 7177 CNRS), Université de
Strasbourg, 67081 Strasbourg, France
________________
This document contains additional bonding parameters for the structurally characterized complexes
2d1, 2f, 2i, 2j and 2n and information relevant to the catalytic testing.
The letters used in the numbering of the complexes refer to the ligand.
When appropriate, the subscript indicates the number of OAr substituents

Electronic Supplementary Material (ESI) for Dalton Transactions
This journal is © The Royal Society of Chemistry 2012
S-2
Fig. 1 ORTEP of the solid state structure of 2d1. H atoms are omitted for clarity. Ellipsoids include
40% of the electron density. Selected bond distances [Å] and angles [°]: Ti1-O1 1.874(2), Ti1-O2
1.785(2), Ti1-O3 1.7700(15), Ti1-O4 1.9423(15), Ti1-O5 2.117(2), Ti2-O4 2.1164(15), Ti2-O5
1.935(2), Ti2-O6 1.863(2), Ti2-O7 1.770(2), Ti2-O8 1.784(2), O1-C1 1.361(3), O6-C27 1.367(3), O1-
Ti1-O2 112.98(8), O1-Ti1-O3 96.87(8), O1-Ti1-O4 123.28(7), O1-Ti1-O5 84.98(7), O2-Ti1-O3
100.14(8), O2 Ti1 O4 117.45(8), O2-Ti1-O5 88.84(7), O3-Ti1-O4 98.24(7), O3-Ti1-O5 169.19(7),
O4-Ti1-O5 72.08(6), O4-Ti2-O5 72.24(6), O4-Ti2-O6 83.76(7), O4-Ti2-O7 168.27(8), O4-Ti2-O8
89.64(7), O5-Ti2-O6 123.95(8), O5-Ti2-O7 97.99(8), O5-Ti2-O8 116.25(8), O6-Ti2-O7 96.95(8), O6-
Ti2-O8 113.34(9), O7-Ti2-O8 100.73(9), Ti1-O4-Ti2 107.68(7), Ti2-O5-Ti1 107.91(7).

Electronic Supplementary Material (ESI) for Dalton Transactions
This journal is © The Royal Society of Chemistry 2012
S-3
Fig. 3 ORTEP of the solid state structure of 2f. H atoms are omitted for clarity. Ellipsoids include
50% of the electron density. Selected bond distances [Å] and angles [°]: Ti-O2 1.8537(15), Ti-O22
2.1112(15), Ti-O22’ 1.9385(15), Ti-O26 1.777(2), Ti-O30 1.787(2), O2-C3 1.352(2), O22-C23
1.447(2), O30-C31 1.416(3); O22-Ti-O2 84.98(6), O22-Ti-O22’ 72.55(7), O2-Ti1-O22’ 120.70(7),
O22-Ti-O26 170.10(7), O2-Ti-O26 97.79(7), O22’-Ti-O26 98.00(7), O22-Ti- O30 87.49(7), O2-Ti-
O30 112.51(7), O22-Ti-O30 120.15(7), O26-Ti-O30 100.11(8), Ti-O2-C3 133.8(1), Ti-O22-C23
117.5(1), Ti-O22-C23 134.4(1).

Electronic Supplementary Material (ESI) for Dalton Transactions
This journal is © The Royal Society of Chemistry 2012
S-4
Fig. 3 ORTEP of the solid state structure of 2j. H atoms are omitted for clarity. Ellipsoids include
40% of the electron density. Selected bond distances [Å] and angles [°]: Ti-O1 1.962(1), Ti-O2
1.959(1), Ti-O3 1.797(1), Ti-O4 1.795(1), Ti-N1 2.2514(15), Ti-N2 2.2359(14); O1-Ti-O2 155.21(5),
O1-Ti-O3 94.37(6), O1-Ti-O4 100.88(6), O2 Ti-O3 101.62(6), O2-Ti-O4 94.03(6), O3-Ti-O4
102.56(6), O1-Ti-N1 75.93(5), O1-Ti-N2 85.11(5), O2-Ti-N1 84.56(5), O2-Ti-N2 76.31(5), O3-Ti-N2
89.51(6), O4-Ti-N2 165.97(6), O3-Ti-N1 165.77(6), O4-Ti-N1 89.65(6), N1-Ti-N2 79.43(5), C1-O1-
Ti 120.7(1), C10-O2-Ti 120.5(1), C19-O3-Ti 149.31(15), C22-O4-Ti 147.0(1).

Electronic Supplementary Material (ESI) for Dalton Transactions
This journal is © The Royal Society of Chemistry 2012
S-5
Fig. 4 ORTEP of the solid state structure of 2n. H atoms are omitted for clarity. Ellipsoids include
40% of the electron density. Selected bond distances [Å] and angles [°]: Ti-O1 1.983(3), Ti-O2
1.874(3), Ti-O3 1.800(3), Ti-O4 1.777(3), Ti-P1 2.5967(15), Ti-P2 2.8764(15), O1-C2 1.339(5), O2-
C28 1.342(5), O3-C53 1.401(6), O4-C56 1.386(8); O4-Ti-O3 100.50(17), O4-Ti-O2 103.50(15), O3-
Ti-O2 100.37(15), O4-Ti-O1 96.30(16), O3-Ti-O1 157.02(16), O2-Ti-O1 90.75(14), O4-Ti-P1
97.68(12), O3-Ti-P1 88.49(12), O2-Ti-P1 155.02(11), O1-Ti-P1 73.74(10), O4-Ti-P2 174.26(12), O3-
Ti-P2 82.74(12), O2-Ti-P2 71.13(10), O1-Ti-P2 81.94(11), P1-Ti-P2 87.10(5), C2-O1-Ti 133.7(3),
C28-O2-Ti 138.0(3), C53-O3-Ti 154.0(4), C56-O4-Ti 162.0(5).

Electronic Supplementary Material (ESI) for Dalton Transactions
This journal is © The Royal Society of Chemistry 2012
S-6
Fig. 5 ORTEP of the solid state structure of 2i. H atoms are omitted for clarity. Ellipsoids include
40% of the electron density. There are two independent, slightly different molecules in the unit cell.
Data for one of them are given below. Selected bond distances [Å] and angles [°]: Ti2-O1 2.2321(15),
Ti2-O2 1.9366(14), Ti2-O3 1.7627(14), Ti2-O4 1.7748(15), Ti2-O5 2.2689(14), Ti2-O6 1.9403(13);
O1-Ti2-O2 80.84(6), O1-Ti2-O3 93.00(7), O1-Ti2-O4 162.29(6), O1-Ti2-O5 74.79(6), O1-Ti2-O6
81.40(6), O2-Ti2-O3 98.23(6), O2-Ti2-O4 95.72(6), O2-Ti2-O5 82.14(5), O2-Ti2-O6 158.23(6), O3-
Ti2-O5 167.61(7), O3-Ti2-O6 95.16(6), O4-Ti2-O5 87.55(6), O4-Ti2-O6 97.38(7), O5-Ti2-O6
81.14(5), C1-O1-Ti2 118.3(1), C19-O1-Ti2 120.2(1), C8-O2-Ti2 129.7(1), C13-O3-Ti2 171.4(2),
C16-O4-Ti2 161.25(14), C32-O5-Ti2 119.47(13), C20-O5-Ti2 116.1(1), C27-O6-Ti2 129.9(1).

Electronic Supplementary Material (ESI) for Dalton Transactions
This journal is © The Royal Society of Chemistry 2012
S-7
Ethylene oligomerization reactor
Example of reaction profil :
Pressure (bar)
C2H4
N2
N2
Temperature (°C)
Ethylene uptake (g)