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Abstract
This thesis is primarily concerned with the development of new multidentate phosphine ligands, the synthesis and reactions of iron and ruthenium complexes of these ligands, with a specific focus on the complexes which incorporate a dinitrogen ligand. All metal complexes were characterized by multinuclear NMR spectroscopy and twenty three single crystal X-ray structures of new complexes were determined.
The synthesis and characterisation of the hindered tripodal phosphine ligand P(CH2CH2CH2PiPr2)3 (P3P3iPr) is described, along with the synthesis and characterization of [RuCl(P3P3iPr)][BPh4], RuH2(P3P3iPr), and [Ru(H2)(H)(P3P3iPr)][BPh4]. [RuCl(P3P3iPr)][BPh4] is fluxional in solution, and low temperature NMR spectroscopy of the complex correlates well with two dynamic processes.
The synthesis and characterization of the extremely hindered phosphine ligands, P(CH2CH2PtBu2)3 (P2P3tBu), PhP(CH2CH2PtBu2)2 (PhP2P2tBu), and P(CH2CH2CH2PtBu2)3 (P3P3tBu) are described, along with the synthesis of their ruthenium chloro complexes. The bulky P2P3tBu and P3P3tBu ligands are the most sterically encumbered PP3-type ligands so synthesized and in all cases, only three phosphorus donors are able to bind to the metal centre. Low temperature solution and solid state 31P{1H} NMR were used to demonstrate the unknown structure of RuCl2(P2P3tBu.
Treatment of RuCl2(P2P3tBu) with a variety of hydride transfer agents afforded four new ruthenium hydrides. The ruthenium complexes with small molecule donors RuH2(CO)(P2P3tBu), RuH2(N2)(P2P3tBu), RuH2(H2)(P2P3tBu), RuHCl(CO)(P2P3tBu) and RuHCl(N2)(P2P3tBu) were also synthesized. The 15N complex, RuH2(15N2)(P2P3tBu)] was also synthesized and studied.
The synthesis of a series of iron and ruthenium complexes with the ligand P2P3Cy, (P(CH2CH2PCy2)3) is described. The iron(0), ruthenium(0), and iron(I) dinitrogen complexes Fe(N2)(P2P3Cy), Ru(N2)(P2P3Cy), and [Fe(N2)(P2P3Cy)]+, and the ruthenium(I) chloro complex RuCl(P2P3Cy) were synthesized by reduction under a nitrogen atmosphere. The iron(II) complex Fe(H2)(P2P3Cy) was also synthesized. The cationic dinitrogen species [Fe(N2)H(P2P3Cy)]+ and [Ru(N2)H(P2P3Cy)]+ were prepared by treatment of and respectively, with one equiv of a weak organic acid
The synthesis and characterization of the carbon centered podand ligand precursor HC2P3Cy is described. A method for the formation of ruthenium hydride complexes with carbon centered podands is developed, utilizing a reaction of between ruthenium dihydride complexes with the ligand precursor. HC2P3Cy. This method is used to produce the ruthenium complexes RuH(CO)(C2P3Cy) and RuH(N2)(C2P3Cy). Attempted reactions of RuH(N2)(C2P3Cy) are also described.