Early transition metal complexes of carbene donors linked to cyclopentadienyl ring analogues or amidine/amidinate moieties

The new indenyl-functionalised NHC potassium salt, 1-[3-(4, 7-dimethylindenylpropyl]-3-<br/>(2,6-diisopropylphenyl)imidazol-2-ylidenepotassium, has been synthesised. Complexes of<br/>titanium, zirconium and chromium containing this ligand and the two carbon bridge analogue,<br/>1-[2-(4,7-dimethylindenyl)ethyl]-3-(2,6-diisopropylphenyl)imidazol-2 ylidene potassium,<br/>have been synthesised and characterised by X-ray crystallographic techniques. The following<br/>complexes were tested as catalysts for the oligomerisation of ethylene in the presence of<br/>MAO: 3-(2,6-diisopropylphenyl)-1-[2-(4,7-dimethylindenyl)ethyl]-imidazol-2-ylidene(tertbutylimido)<br/>titanium chloride, 3-(2,6-diisopropylphenyl)-1-[3-(4,7-<br/>dimethylindenyl)propyl]imidazol-2-ylidene(tert-butylimido)titanium chloride, 3-(2,6-<br/>diisopropylphenyl)-1-[3-(4,7-dimethylindenyl)propyl]imidazol-2-ylidenezirconium<br/>trichloride, 3-(2,6-diisopropylphenyl)-1-[2-(4,7-dimethylindenyl)ethyl]imidazol-2-<br/>ylidenezirconium trichloride, 3-(2,6-Diisopropylphenyl)-1-[2-(4,7-dimethylindenyl)ethyl]-<br/>imidazol-2-ylidenechromium dichloride, 3-(2,6-diisopropylphenyl)-1-[3-(4,7-<br/>(dimethylindenyl)propyl]imidazol-2-ylidene chromium dichloride, 3-(2,6-diisopropylphenyl)-<br/>1-[3-(4,7-dimethylindenyl)propyl]-imidazol-2-ylidene chromium methyl chloride and 3-(2,6-<br/>diisopropylphenyl)-1-[2-(4,7-dimethylindenyl)ethyl]-imidazol-2-ylidenevanadium dichloride.<br/><br/>The following alkyl chromium complexes containing 1-[2-(4,7-dimethylindenyl)ethyl]-3-(2,6-<br/>diisopropylphenyl)imidazol-2 ylidene potassium have also been synthesised: 3-(2,6-<br/>diisopropylphenyl)-1-[2-(4,7-dimethylindenyl)ethyl]-imidazol-2-ylidene chromium phenyl<br/>chloride and 3-(2,6-diisopropyl-phenyl)-1-[2-(4, 7-dimethylindenyl)ethyl]-imidazol-2-ylidene<br/>chromium dibenzyl. Chromium cations have been synthesised using as starting materials the<br/>chromium alkyl complexes. The Cr(II) complex 3-(2,6-diisopropyl-phenyl)-1-[2-(4, 7-<br/>dimethylindenyl)ethyl]-imidazol-2-ylidene chromium monochloride and a partially oxidised<br/>dimerised product were also isolated. 5-(2-chloroethyl)- 1, 2, 3, 4-tetramethylcyclopentadiene<br/>and 5-(3-chloropropyl) 1, 2, 3, 4-tetramethylcyclopentadiene were synthesised and isolated as<br/>geminal isomers for the first time.<br/><br/>The trialkyl chromium complex, tribenzyl chromium tris(tetrahydrofuran) was synthesised<br/>and also it was used as starting material for the complexes di(benzyl)chromium bis(1, 3-<br/>diisopropylimidazol-2-ylindene) and tri(benzyl)chromium TACN. All complexes were<br/>characterised by X-ray crystallography.<br/><br/>The imidazolium salt 3-(2.6-diisopropylphenyl)-1-[N, N-bis(2,6-<br/>diisopropylphenyl)acetamidyl] imidazolium chloride was synthesised and used as a precursor<br/>for the synthesis of amidinate-functionalised NHC zirconium and amidine-functionalised<br/>NHC silver complexes. Double deprotonation of 3-(2,6-diisopropylphenyl)-1-[N, N’-bis(2,6-<br/>diisopropylphenyl)acetamidyl] imidazolium chloride gave the amidinate-functionalised NHC<br/>ligand, 3-(2.6-diisopropylphenyl)-1-[2-N, N’bis(2,6<br/>diisopropylphenylamidinate)ethyl]imidazol-2-ylidenepotassium. Titanium, zirconium and<br/>chromium complexes containing this ligand were synthesised and characterised by X-ray<br/>crystallographic techniques. Transmetallation of the amidine-functionalised NHC silver<br/>complex with [Rh(COD)Cl]2 and [Ir(COD)Cl]2 gave the corresponding species. Rh(amidinefunctionalised<br/>NHC)(COD)Cl reacted with Na(BAr)4 (Ar = 3,5-CF3C6H3) to give the cation<br/>Rh(amidine-functionalised NHC)(COD)]+[BAr4]-. These species were also characterised by<br/>X-ray diffraction techniques.

Name dc:type.qualificationname

Ph.D.

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

University of Southampton

Year dc:date.issued

2010

Author dc:creator

• Conde Guadano, Susana

Advisor dc:contributor.advisor

• Danopoulos, Andreas A.