Electronic Thesis and Dissertation Repository


Doctor of Philosophy




Richard Puddephatt

2nd Supervisor

Johanna Blacquiere

Joint Supervisor


This thesis describes the synthesis and reactivity of complexes containing the cycloneophyl-Pd(II) group, PdCH2CMe2C6H4, in combination with N-donor ligands. These compounds contain both alkyl- and arylpalladium bonds and the selectivity of bond cleavage in reactions with oxidants and protic reagents is studied, often involving oxidative addition and reductive elimination reaction sequences.

The diimine ligand in [Pd(CH2CMe2C6H4)(MesN=CH-CH=NMes)] does not support formation of stable palladium(IV) complexes, but reactions with Br2 or I2 lead to reductive elimination by C-C bond formation of 1,1-dimethylcyclobutabenzene while the reaction with H2O2 gives [Pd(CH2CMe2C6H4O)(MesN=CH-CH=NMes)] by overall selective oxygen atom insertion into the aryl-palladium bond.

Coordination of the ligand 2-C5H4NCH=N-2-C6H4OH, 3-L1H, led to protonolysis of the arylpalladium bond to give a neophyl complex [Pd(CH2CMe2C6H5)(k3-N,N',O-3-L1)], which then isomerized to [Pd(2-C6H4-t-Bu)(k3-N,N',O-3-L1)], by a sequence of reactions that includes reversible C-H bond activation. The combination of a Pd(II) precursor with a diimine-phenol ligand and an oxidant (H2O2 or O2) under different conditions has given both a molecular square and a molecular tetrahedron by self-assembly of building blocks comprising Pd(II) centres coordinated to oxidized forms of the ligand.

The complex [Pd(CH2CMe2C6H4){κ2-N,N’-N(CH2-2-C5H4N)2(CH2CH2CH2OH)}] reacted with aqueous CO2 and H2O2 to give complex [Pd(CO3){κ3-N,N’,N’’-N(CH2-2-C5H4N)2(CH2CH2CH2OH)}], and organic products resulting from a unique form of neophyl rearrangement. The complexes [Pd(CH2CMe2C6H4)(κ2-N,N-L)], L = RO(CH2)3N(CH2−2-C5H4N)2, R = H or Me, react with Br2, I2, O2 or H2O2 to give Pd(IV) complexes which are sufficiently stable to isolate or to detect spectroscopically, but which decompose slowly in solution by reductive elimination.