Doctor of Philisophy (PhD) / Despite their early discovery, relatively few classes of ruthenium dinitrogen complexes are known. This work describes the successful coordination of dinitrogen to the electron-rich alkylphosphine cores [RuCl(dmpe)2]+ and [RuCl(depe)2]+ by chloride abstraction from both the cis and trans dichloro derivatives. One such complex, trans-[RuCl(N2)(dmpe)2](BArF24), possesses the most activated ruthenium νNN reported to date. A variety of chloride abstraction agents were tested on the cis and trans isomers of [RuCl2(P-P)2] (P-P = dmpe, depe) with the choice of abstracting agent, anion and solvent all found to significantly affect the outcome. Reaction with silver triflate and trimethylsilyl triflate was found to give dichlororuthenium(III) products, which could be readily reduced to the ruthenium(II) starting materials with common reducing agents, as well as by alcohols and hydrazine. The use of thallium triflate avoided oxidation and led to the formation of the crystallographically characterised polymeric incorporation product, [{trans-[RuCl2(dmpe)2]•Tl(OTf)}n] from trans-[RuCl2(dmpe)2] and the interesting chloride-bridged ruthenium dimer cis-[{Ru(depe)2}2(μ-Cl)2](OTf)2 from trans-[RuCl2(depe)2]. Anion exchange of the complex [{trans-[RuCl2(dmpe)2]•Tl(OTf)}n] with the non-coordinating anion tetrakis(3,5-bis(trifluoromethyl)phenyl)borate resulted in removal of thallium from the system and coordination of dinitrogen to give trans-[RuCl(N2)(dmpe)2](BArF24). Cis-[{Ru(depe)2}2(μ-Cl)2](OTf)2 was found to readily react with a variety of small ligands and gave products such as cis-[RuCl(CO)(depe)2](OTf), cis-[RuCl(NCMe)(depe)2](OTf), cis-[RuCl(CNtBu)(depe)2](OTf), cis-[RuCl(NH3)(depe)2](OTf), cis-[RuCl(N3)(depe)2], and trans-[RuCl(η2-H2)(depe)2](OTf). A preliminary X-ray single crystal structure analysis was conducted on the complex cis-[RuCl(CNtBu)(depe)2](OTf). The thallium(I) salt Tl(BArF24) was found to be an efficient chloride abstraction agent under mild conditions. Reactions with cis- and trans-[RuCl2(depe)2] and cis-[RuCl2(dmpe)2] furnished dinitrogen complexes of the form cis-[{RuCl(P-P)2}2(μ-N2)](BArF24)2, whilst reaction of trans-[RuCl2(dmpe)2] with Tl(BArF24) led to the stable five-coordinate complex trans-[RuCl(dmpe)2](BArF24). Vapour diffusion techniques applied to a solution of cis-[{RuCl(depe)2}2(μ-N2)](BArF24)2 gave rise to crystals of trans-[RuCl(N2)(depe)2](BArF24), on which preliminary X-ray molecular structure analysis was performed. Reactions of both cis-[{Ru(depe)2}2(μ-Cl)2](OTf)2 and trans-[RuCl2(dmpe)2] with high pressure (140 psi) dinitrogen at 140 150°C in methanol or tetrahydrofuran resulted in solvent carbonyl abstraction to afford trans-[RuCl(CO)(depe)2](OTf) and trans-[RuCl(CO)(dmpe)2](Cl) from the depe and dmpe complexes respectively. The molecular structure of trans-[RuCl(CO)(dmpe)2](Cl) was determined via single crystal X-ray structure analysis.
| Identifer | oai:union.ndltd.org:ADTP/189126 |
| Date | January 2008 |
| Creators | Tronoff, Ashley |
| Publisher | Science, School of Chemistry |
| Source Sets | Australiasian Digital Theses Program |
| Detected Language | English |
| Rights | The author retains copyright of this thesis., http://www.library.usyd.edu.au/copyright.html |
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