The organometallic Lewis acid [(η5-C5H5)(CO)2Fe]BF4 reacts with excess dry diethyl ether at low temperatures to form the novel labile complex [(η5-C5H5)(CO)2Fe(OEt2)]BF4 which in turn serves as a precursor in the syntheses of various cationic dicarbonylcyclopentadienyliron complexes. The reactions of [(η5-C5H5)(CO)2Fe(OEt2)]BF4 with various 1-alkylamines, α,ω-diaminoalkanes, N-heterocyclics and heterofunctional amine ligands, as well as olefins, have been investigated. Reactions with 1-alkylamines and α,ω-diaminoalkane ligands lead to a series of novel monuclear and dinuclear complexes of the types [(η5-C5H5)(CO)2FeL]BF4 and [{(η5-C5H5)(CO)2Fe}2(μ-L)](BF4)2, respectively. The reaction of [(η5-C5H5)(CO)2Fe(OEt2)]BF4 with N-heterocyclic ligands such as 1,3,5,7-tetraazaadamantane (HMTA) and 1,4-diazabicyclo[2.2.2]octane (DABCO) give dinuclear complexes [{(η5-C5H5)(CO)2Fe}2(μ-L)](BF4)2 and monuclear complexes [(η5-C5H5)(CO)2FeL]BF4 (L = HMTA, DABCO). Its reaction with 1-methylimidazole (1-meIm) affords only the monuclear complex [(η5-C5H5)(CO)2Fe(1-meIm)]BF4 in which the coordination of 1-methylimidazole is via the sp2-N. The reaction with heterofunctional amine ligands is highly regioselective with the cation [(η5-C5H5)(CO)2Fe]+ showing higher affinity for NH2 than π-bonded, O or CN functionalities. Besides amines, [(η5-C5H5)(CO)2Fe(OEt2)]BF4 reacts with olefins and HCOOH to form complexes of the type [(η5-C5H5)(CO)2Fe(η2-olefin)]BF4 and [{(η5-C5H5)Fe(CO)2}2(μ-OCHO)]BF4, respectively.
For comparison of steric and electronic effects, analogous pentamethylcyclopentadienyl amine complexes were synthesized from the THF complex [{η5-C5(CH3)5}(CO)2Fe(THF)]BF4. The reaction of 3-aminoprop-1-ene with the etherate complexes [(η5-C5R5)(CO)2Fe(E)]BF4 (R = H: E= Et2O; R = CH3: E = THF) led to air stable complexes [(η5-C5R5)(CO)2Fe(NH2CH2CHCH2)]BF4 (R = H, CH3), which in turn react with a mole equivalent of the etherate complexes to give dinuclear complexes of the type, [(η5-C5R5)(CO)2Fe(NH2CH2CHCH2)Fe(CO)2(η5-C5R'5)](BF4)2 (R not necessarily equal to R'). They also undergo halogenation to give the chiral dihalopropylamino complexes [(η5-C5R5)(CO)2Fe(NH2CH2CH(X)CH2(X))]BF4 (R=H, CH3; X = Cl, Br). The reaction of the dinuclear complex [{(η5-C5H5)(CO)2Fe}2(NH2CH2CHCH2](BF4)2 with NaI in acetone gives [(η5-C5H5)(CO)2Fe(NH2CH2CHCH2)]I and [(η5-C5H5)Fe(CO)2I]. All these complexes have been fully characterized by 1H NMR, 13C NMR, IR spectroscopy and elemental analysis. The mass spectra of 1-aminoalkane and diaminoalkane complexes have also been recorded and are discussed. The structures of 16 synthesized compounds have been confirmed by single crystal X-ray crystallography. Most of the amine complexes are water-soluble and some undergo counteranion exchange with sodium tetraphenylborate in both aqueous and organic media to give BPh4- salts. / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2011.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ukzn/oai:http://researchspace.ukzn.ac.za:10413/9666 |
| Date | 03 October 2013 |
| Creators | M'thiruaine, Cyprian Muturia. |
| Contributors | Friedrich, Holger Bernhard., Changamu, Evans O. |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
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