A family of group 4 permethylpentalene complexes, Pn*MCpRX (M = Ti, Zr; CpR = Cp, CpMe, CptBu, CpnBu, CpMe3, Ind; X = Cl, Me) has been synthesised and fully characterised by multinuclear NMR spectroscopy, elemental analysis, and single-crystal X-ray diffraction studies. The effect of substitution around the Cp ligand was examined for ethylene polymerisation

A series of group 4 complexes η5-Pn*(H)TiCl3, [η5-Pn*(H)ZrCl3]2 and [η5-Pn*(H)HfCl3]2 containing a η5-permethylpentalene ligand were prepared by the reaction of η5-Pn*(H)SnMe3 with the corresponding group 4 starting materials. The complexes inititiated ring opening polymerisation of L- and rac-lactide.


We describe the synthesis, structure and bonding of the first iridium and rhodium permethylpentalene complexes, syn-[M(CO)2]2(μ:η55-Pn*) (M = Rh, Ir). In fact, [Ir(CO)2]2(μ:η55-Pn*) is the first iridium pentalene complex. The novel 14 electron species η8-Pn*TiR2 (Pn* = C8Me6; R = Me, CH2Ph) have been synthesised and spectroscopically and structurally characterised. Subsequent reaction with CO2 leads to the activation and double insertion of CO2into both Ti–alkyl bonds to form the electronically saturated η8-Pn*Ti(κ2-O2CR)2 (R = Me, CH2Ph) complexes.


Recent publications:

Titanium and Zirconium Permethylpentalene Complexes, Pn*MCpRX, as Ethylene Polymerization Catalysts, D. A. X. Fraser, Z. R. Turner, J.-C. Buffet and D. O’Hare, Organometallics, (2016), 35, 2664-2674.

Zirconium and Hafnium Permethylpentalene Compounds, F. M. Chadwick, R. T. Cooper and D. O’Hare, Organometallics, (2016), 35, 2092-2100.

Group 9 Bimetallic Carbonyl Permethylpentalene Complexes, F.M. Chadwick, A.E. Ashley, R.T. Cooper, L.A. Bennett, J.C. Green and D. O’Hare, Dalton Trans., (2015), 44, 20147-20153.

Double CO2 Activation by 14-electron η8-Permethylpentalene Titanium Dialkyl Complexes, R.T. Cooper, F.M. Chadwick, A.E. Ashley and D. O’Hare, Chemical Communications, (2015), 5, 11856 – 11859.

Synthesis and Characterization of Chiral Group 4 Cyclopentadienyl Complexes and their use in Polymerization of Lactide Monomers, Z.R. Turner, J.-C. Buffet and D. O’Hare, Organometallics, (2014), 33 (14), 3891–3903.