We use cookies to ensure that we give you the best experience on our website. By continuing to browse this repository, you give consent for essential cookies to be used. You can read more about our Privacy and Cookie Policy.

Durham e-Theses
You are in:

Some aspects of organonitrogen transition metal complexes

Clark, John Andrew (1982) Some aspects of organonitrogen transition metal complexes. Doctoral thesis, Durham University.



Attempts to introduce amidino ligands into Transition metal carbonyl and non carbonyl systems are described, and a new synthetic route to transition metal methyleneamino complexes is explored. Reaction of lithiodiaryl -acetamidines and -benzamidines with Re(CO) (_5)X (X = C1,Br) produced carbamoyl type complexes, Re(CO)(_4)(CONR-CR'-NR) containing a bidentate carbamoyl-amidino ligand. These complexes could be decarbonylated, forming the chelated amidino complexes Re(CO)(_4)(RN-CR'-NR) by heating. The chelated amidino complexes were also prepared by the direct action of lithioamidines on the rhenium carbonyhalide dimer [Re(CO)(_4)X](_2), and by the reaction of n-butyllithium with the simple two electron donor monodentate amidine complexes, Re(CO)(_4)(Amidine)X. Complexes containing ortho-metallated diaryl -formamidino, -acetamidino and -benzamidino ligands were prepared by the action of the parent amidine on Re(CO)(_5)X or Re(CO)(_4)(Amidine)X in refluxing monoglyme. These complexes also contained a simple two electron donor monodentate amidine. The acetamidine and formamidine derivatives formed six membered ortho-metallate rings, the benzamidines forming either five or six membered ring complexes. In contrast, refluxing Re(CO)(_4)(Amidine)X with PPh(_3) in monoglyme produced a chelated amidino species, Re(C0)(_3)(PPh(_3))(RN-CR'-NR). The reaction mechanisms for the formation of the above complexes, and their probable bonding modes are discussed. Interconversions between many of the species were possible. FeCl(_2) reacts with lithiodiarylamidines to produce [Fe(amidino)(_3)](_n) type complexes. The acetamidines and formamidines form monomeric complexes (with a probable tris chelate structure), and the benzamidine forms both a monomeric and an oligomeric/polymeric complex. FeCl reacts similarly with lithiumdi-p-tolylacetamidine, both monomeric and oligomeric/polymeric [Fetamidine)(_2)](_n) species being produced. The complexes are paramagnetic, the Fe(III) species have magnetic moments that suggest they contain five unpaired electrons. Nucleophilic attack by n-butyllithium at the carbon atom of [CpMo(CO)(AsPh(_3)) (NCPh) ](^+) did not produce a methyleneamino complex. Free nitrile was liberated in the reaction, and dimeric molybdenum complexes were produced.

Item Type:Thesis (Doctoral)
Award:Doctor of Philosophy
Thesis Date:1982
Copyright:Copyright of this thesis is held by the author
Deposited On:15 Jul 2013 14:42

Social bookmarking: del.icio.usConnoteaBibSonomyCiteULikeFacebookTwitter