Exploratory studies of novel ligand systems
- Authors: Taylor, Steven John
- Date: 1992
- Subjects: Ligands , Coordination compounds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4315 , http://hdl.handle.net/10962/d1004973 , Ligands , Coordination compounds
- Description: A range of novel ligand systems have been developed in three distinct phases and preliminary studies have been initiated to evaluate their complexation potential. Phase I incorporated the synthesis of single strand ligand systems, which were mainly based on amino acid residues. Techniques have been developed for the attachment of these ligand systems onto, firstly, a styrene monomer, and then later onto a pseudo-styrene linking group, viz. the p-toluoyl group. The linking reactions were based on the formation of amides or esters by the reaction of an acid chloride system with an amine or alcohol. Phase II involved the synthesis of bis-chain ligand systems and their attachment onto the p-toluoyl linking group. A further linking group was also developed at this stage, viz. the xylyl group. In the preparation of phase II ligand systems, use was made of malonic ester and iminodiacetic acid derivatives. Phase III has involved the synthesis of cyclic ligand systems, with skeletons based upon the structures used in phase I and phase II and two crown ether type systems have been prepared.
- Full Text:
- Date Issued: 1992
- Authors: Taylor, Steven John
- Date: 1992
- Subjects: Ligands , Coordination compounds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4315 , http://hdl.handle.net/10962/d1004973 , Ligands , Coordination compounds
- Description: A range of novel ligand systems have been developed in three distinct phases and preliminary studies have been initiated to evaluate their complexation potential. Phase I incorporated the synthesis of single strand ligand systems, which were mainly based on amino acid residues. Techniques have been developed for the attachment of these ligand systems onto, firstly, a styrene monomer, and then later onto a pseudo-styrene linking group, viz. the p-toluoyl group. The linking reactions were based on the formation of amides or esters by the reaction of an acid chloride system with an amine or alcohol. Phase II involved the synthesis of bis-chain ligand systems and their attachment onto the p-toluoyl linking group. A further linking group was also developed at this stage, viz. the xylyl group. In the preparation of phase II ligand systems, use was made of malonic ester and iminodiacetic acid derivatives. Phase III has involved the synthesis of cyclic ligand systems, with skeletons based upon the structures used in phase I and phase II and two crown ether type systems have been prepared.
- Full Text:
- Date Issued: 1992
Solvent-free synthesis of bisferrocenylimines and their coordination to rhodium (I)
- Authors: Kleyi, Phumelele Eldridge
- Date: 2009
- Subjects: Organic compounds -- Synthesis , Organic solvents , Solution (Chemistry) , Chemistry, Organic , Coordination compounds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10393 , http://hdl.handle.net/10948/1053 , Organic compounds -- Synthesis , Organic solvents , Solution (Chemistry) , Chemistry, Organic , Coordination compounds
- Description: Solvent-free reactions possess advantages compared to the solvent route, such as shorter reaction times, less use of energy, better yields, etc. Herein, the synthesis and characterization of bisferrocenylimines and arylbisamines are described. Reduction of the above compounds with LAH resulted in the formation of bisferrocenylamines and arylbisamines, respectively. The coordination chemistry of all the above compounds to rhodium(I) is also discussed in the prepared complexes [Rh(COD)(NN)]ClO4, where NN = bisferrocenylimines, and [Rh(COD)(NN)]BF4, where NN = bisferrocenylamines and arylbisamines. X-ray crystal structures of the complexes [Rh(COD)(NN)]ClO4 ([3.2] and [3.3]) have been obtained. Complexes of the type [Rh(COD)(NN)]BF4 were characterized with IR and UV-vis spectroscopy, cyclic voltammetry and conductometry. The catalytic activity of the complexes was also investigated: [Rh(COD)(NN)]ClO4 for the polymerization of phenylacetylene and [Rh(COD)(NN)]BF4 for the hydroformylation of styrene.
- Full Text:
- Date Issued: 2009
- Authors: Kleyi, Phumelele Eldridge
- Date: 2009
- Subjects: Organic compounds -- Synthesis , Organic solvents , Solution (Chemistry) , Chemistry, Organic , Coordination compounds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10393 , http://hdl.handle.net/10948/1053 , Organic compounds -- Synthesis , Organic solvents , Solution (Chemistry) , Chemistry, Organic , Coordination compounds
- Description: Solvent-free reactions possess advantages compared to the solvent route, such as shorter reaction times, less use of energy, better yields, etc. Herein, the synthesis and characterization of bisferrocenylimines and arylbisamines are described. Reduction of the above compounds with LAH resulted in the formation of bisferrocenylamines and arylbisamines, respectively. The coordination chemistry of all the above compounds to rhodium(I) is also discussed in the prepared complexes [Rh(COD)(NN)]ClO4, where NN = bisferrocenylimines, and [Rh(COD)(NN)]BF4, where NN = bisferrocenylamines and arylbisamines. X-ray crystal structures of the complexes [Rh(COD)(NN)]ClO4 ([3.2] and [3.3]) have been obtained. Complexes of the type [Rh(COD)(NN)]BF4 were characterized with IR and UV-vis spectroscopy, cyclic voltammetry and conductometry. The catalytic activity of the complexes was also investigated: [Rh(COD)(NN)]ClO4 for the polymerization of phenylacetylene and [Rh(COD)(NN)]BF4 for the hydroformylation of styrene.
- Full Text:
- Date Issued: 2009
The coordination and extractive chemistry of the later 3d transition metal ions with N, N'-donor imidazole-based ligands
- Authors: Moleko, Pulleng
- Date: 2014
- Subjects: Solvent extraction , Coordination compounds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/8382 , vital:26352
- Description: The application of bidentate N,N'-donor ligands, such as 2,2'-biimidazole (BIIMH2) and 2,2'-pyridylimidazole (PIMH) and (1H-benzimidazol-2yl)-N-methylmethanamine (BIMAH), in the solvent extraction of base metal ions from an acidic sulfate/sulfonate medium was investigated. PIMH and BIMAH showed selectivity for Ni(II) with the only interfering ion being Cu(II) in the pH range 1.2-1.8 but BIIMH2 lacked selectivity. The extraction patterns observed were influenced by stereochemical aspects, and this agreed well with the envisaged design of nickel(II)-specific extractants through stereochemical “tailor-making” which is proposed in this study. The extraction patterns were explained from a coordination chemistry point of view using spectroscopic analysis and single crystal X-ray analysis to diagnose the geometry of the complexes formed from the interaction of the base metal ions with the ligands. The formation of the trigonal bipyrimidal [Cu(PIM)2(H2O)](SO4) complex, with a water molecule coordinated, while nickel(II) forms a square planar bisPIMH was put forward as the reason for extraction pattern observed with this ligand. Cobalt(II) also forms a bisPIMH complex but has two water molecules coordinated in the formation of a distorted octahedral complex, and this results in less extractable species. A similar observation as for PIMH was noticed in BIMAH complexation reactions. The BIIMH2 complexes were found to be distorted octahedral, through the bis-coordination of BIIMH2 and two sulfonate ions, resulting in lack of pH-metric separation of the later 3d metal ions. The stability constants data was in agreement with what was observed in the solvent extraction and coordination chemistry studies for the three ligand systems.
- Full Text:
- Date Issued: 2014
- Authors: Moleko, Pulleng
- Date: 2014
- Subjects: Solvent extraction , Coordination compounds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/8382 , vital:26352
- Description: The application of bidentate N,N'-donor ligands, such as 2,2'-biimidazole (BIIMH2) and 2,2'-pyridylimidazole (PIMH) and (1H-benzimidazol-2yl)-N-methylmethanamine (BIMAH), in the solvent extraction of base metal ions from an acidic sulfate/sulfonate medium was investigated. PIMH and BIMAH showed selectivity for Ni(II) with the only interfering ion being Cu(II) in the pH range 1.2-1.8 but BIIMH2 lacked selectivity. The extraction patterns observed were influenced by stereochemical aspects, and this agreed well with the envisaged design of nickel(II)-specific extractants through stereochemical “tailor-making” which is proposed in this study. The extraction patterns were explained from a coordination chemistry point of view using spectroscopic analysis and single crystal X-ray analysis to diagnose the geometry of the complexes formed from the interaction of the base metal ions with the ligands. The formation of the trigonal bipyrimidal [Cu(PIM)2(H2O)](SO4) complex, with a water molecule coordinated, while nickel(II) forms a square planar bisPIMH was put forward as the reason for extraction pattern observed with this ligand. Cobalt(II) also forms a bisPIMH complex but has two water molecules coordinated in the formation of a distorted octahedral complex, and this results in less extractable species. A similar observation as for PIMH was noticed in BIMAH complexation reactions. The BIIMH2 complexes were found to be distorted octahedral, through the bis-coordination of BIIMH2 and two sulfonate ions, resulting in lack of pH-metric separation of the later 3d metal ions. The stability constants data was in agreement with what was observed in the solvent extraction and coordination chemistry studies for the three ligand systems.
- Full Text:
- Date Issued: 2014
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