Syntheses, electrochemical and spectroelectrochemical properties of novel ball-type and mononuclear Co (II) phthalocyanines substituted at the peripheral and non-peripheral positions with binaphthol groups
- Authors: Canlıca, Mevlüde , Booysen, Irvin Noel , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247837 , vital:51622 , xlink:href="https://doi.org/10.1016/j.poly.2010.11.017"
- Description: Mononuclear cobalt phthalocyanine (CoPc) substituted at the non-peripheral 8 and peripheral positions 9 with 1,1′-binaphthyl-8,8′-diol and ball-type dinuclear Co2Pc2 substituted at the non-peripheral 10 and peripheral 11 positions with the same substituent are reported. The complexes with 1,1′-binaphthol-bridges were prepared from the corresponding phthalonitriles 4–7. The effects of the position of substituent on spectral, electrochemical and spectroelectrochemical properties of these complexes were also explored. The mononuclear complexes 8 and 9 exhibited one metal reduction, one ring reduction and one ring oxidation. The redox properties of the ball-type complexes 10 and 11 exhibited two reduction processes assigned to [(CoIPc−2)2]2−/[(CoIPc−3)2]4− (I), (CoIIPc−2)2/[(CoIPc−2)2]2− (II) and one oxidation process assigned to [(CoIIIPc−2)2]2+/CoIIPc−2)2 (III). The ball-type complexes are much easier to oxidize and more difficult to reduce than the corresponding monomers 8 and 9.
- Full Text:
- Date Issued: 2011
Synthesis and electrochemical behavior of novel peripherally and non-peripherally substituted ball-type cobalt phthalocyanine complexes
- Authors: Canlıca, Mevlüde , Booysen, Irvin Noel , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247848 , vital:51623 , xlink:href="https://doi.org/10.1016/j.poly.2010.11.028"
- Description: The syntheses of new ball-type Co(II) phthalocyanines containing 4,4′-(9H-fluorene-9,9-diyl)diphenol substituents at non-peripheral (complex 6) and peripheral (complex 7) positions are presented. These complexes were characterized by UV–Vis, FT-IR, mass spectroscopy and electrochemical methods. Both complexes exhibit metal and ring based redox processes, typical of cobalt phthalocyanine complexes. For 6, the metal based reduction was observed at −0.46 V followed by a ring based reduction at −1.40 V. The metal oxidation for 6 was observed at +0.16 V and the ring based oxidation at +1.05 V. For 7, reductions are easier but the oxidations are more difficult. The metal based reduction for 7 was observed at −0.38 V followed by a ring based reduction at −1.03 V. The metal oxidation for 7 was observed at +0.20 V and the ring based oxidation at +1.35 V.
- Full Text:
- Date Issued: 2011
Synthesis and electrochemical properties of new tetra substituted cobalt phthalocyanine complexes, and their application in electrode modification for the electrocatalysis of l-cysteine
- Authors: Erdoğmuş, Ali , Booysen, Irvin Noel , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247893 , vital:51627 , xlink:href="https://doi.org/10.1016/j.synthmet.2010.11.028"
- Description: This study investigates the synthesis and characterization new peripherally (β) tetra-substituted 4-(2-mercaptoquinoline phthalocyaninato) Co(II) (CoPcSHQn, 3), and 4-(2-phenoxy-4-trifluoromethylpyridine phthalocyaninato) Co(II) (CoPcOHPy, 4). These complexes were characterized by elemental analysis, IR, mass and electronic spectroscopies and electrochemical methods. Both complexes show well resolved redox peaks attributed to both ring and metal based processes. Spectroelectrochemistry was used to confirm the assignments of the redox processes. For CoPcSHQn (3): CoIPc−2/CoIPc−3 (E1/2 = −1.25 V, I), CoIIPc−2/CoIPc−2 (E1/2 = −0.57 V, II), CoIIIPc−2/CoIIPc−2 (E1/2 = +0.45 V, IV) and an irreversible process at Ep = +1.05 V vs Ag|AgCl for CoIIIPc−1/CoIIIPc−2 (V). Redox couple III at E1/2 = −0.15 V was ascribed to aggregation. In the case of CoPcOHPy (4): CoIPc−2/CoIPc−3 (E1/2 = −1.13 V, I), CoIIPc−2/CoIPc−2 (E1/2 = −0.45 V, II), CoIIIPc−2/CoIIPc−2 at E1/2 = +0.21 V (IV), and CoIIIPc−1/CoIIIPc−2 (E1/2 = +1.01 V vs Ag|AgCl, V). Again III is associated with the aggregated species. Both complexes were electrodeposited on a glassy carbon electrode (GCE). For complex 3 self-assembled monolayers was also formed. The modified (CoPc-GCE) electrodes electrocatalytically detected L-cysteine at Ep = 0.62 V (3-GCE) and 0.59 V (4-GCE) vs Ag|AgCl.
- Full Text:
- Date Issued: 2011
Rhenium (I) and (V) complexes with potentially mulidentate ligands containing the Amino group
- Authors: Booysen, Irvin Noel
- Date: 2009
- Subjects: Rhenium , Ligands
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10386 , http://hdl.handle.net/10948/1270 , Rhenium , Ligands
- Description: The complex trans-[Re(dab)Cl3(PPh3)2] (H2dab = 1,2-diaminobenzene) was prepared from the reaction of trans-[ReOCl3(PPh3)2] with H2dab in ethanol. The ligand dab is coordinated to the rhenium(V) centre through a dianionic imido nitrogen only in a distorted octahedral coordination geometry around the metal ion. The complex trans- [Re(ada)Cl3(PPh3)2] (H2ada = 2-aminodiphenylamine) was prepared from the reaction of trans-[ReOCl3(PPh3)2] with H2ada in acetonitrile. The ligand ada is coordinated to the rhenium(V) centre through a dianionic imido nitrogen only, in a distorted octahedral coordination geometry around the metal ion. The ‘2 + 1’ complex fac- [Re(CO)3(Hamp)(amp)] (Hamp = 2-aminophenol) was isolated from the reaction of a two molar ratio of Hamp with [Re(CO)5Br] in toluene. The reaction of a 1:1 molar ratio of [Re(CO)5Br] and H2ada led to the isolation of the Re(I) complex, fac- [Re(CO)3Br(H2ada)]. The reaction of equimolar quantities of cis-[ReO2I(PPh3)2] with 5,6-diamino-1,3- dimethyluracil (H2ddd) in acetonitrile led to the formation of [Re(ddd)(Hddd)I(PPh3)2](ReO4). The X-ray crystal structure shows that the ligand ddd is coordinated monodentately through the doubly deprotonated amino nitrogen and is therefore present as an imide. The chelate Hddd is coordinated bidentately via the neutral amino nitrogen, which is coordinated trans to the imido nitrogen, and the singly deprotonated amido nitrogen, trans to the iodide. The reaction of trans-[ReOCl3(PPh3)2] with N-(2-aminobenzylidene)-5-amino-1,3-dimethyl uracil (H3dua) in ethanol gave a mixed crystal which contains both the neutral oxorhenium(V) complex [ReOCl(Hdua)] and the imido rhenium(V) [Re(dua)Cl2(PPh3)] in an equimolar ratio in the asymmetric unit. The reaction of equimolar quantities of [NH4(ReO4)] with H2ddd in methanol under reflux led to the isolation of [C12H12N6O4] as only product. The [ReO4]- anion is therefore instrumental in the formation of [C12H12N6O4], and since the product contains no rhenium in any oxidation state, the conclusion is that [ReO4]- catalyses the oxidative deamination Abstract I.N. Booysen Nelson Mandela Metropolitan University vii of H2ddd. The X-ray crystal structure consists of two centrosymmetric, tricyclic rings, comprising a central pyrazine ring and two terminal pyrimidine rings. The reaction of 2-(2-aminophenyl)benzothiazole (Habt) with [Re(CO)5Br] led to the isolation of the rhenium(I) complex fac-[Re(Habt)(CO)3Br]. With trans-[ReOCl3(PPh3)2], the ligand Habt decomposed to form the oxofree rhenium(V) complex [Re(itp)2Cl(PPh3)] (itp = 2-amidophenylthiolate). From the reaction of trans-[ReOBr3(PPh3)2] with 2-(2- hydroxyphenyl)benzothiazole (Hhpd) the complex [ReVOBr2(hpd)(PPh3)] was obtained. The reaction of a twofold molar excess of H2apb (2-(2-aminophenyl)-1-benzimidazole) with trans-[ReO2(py)4]Cl in ethanol gave the green product of formulation [ReO(Hapb)(apb)] in good yield. The rhenium atom lies in a distorted trigonalbipyramidal environment. The two imidazole N(2) atoms lie in the apical positions trans to each other, with the oxo-oxygen and two amido N(1) atoms in the trigonal plane. A new nitrosylrhenium(II) complex salt, [Re(NO)BrL2(PPh3)2](ReO4) (H2L2 = 2-amino-5- (triphenylphosphino)phenol), is the first example of a complex containing the triphenylphosphonium-amidophenolate ligand L2, formed by the nucleophilic attack of a PPh3 on a coordinated amidophenolate ring. The complex salt trans-[Re(mps)Cl(PPh3)2](ReO4) (H3mps = N-(2-amino-3- methylphenyl)salicylideneimine) was prepared by the reaction of trans-[ReOCl3(PPh3)2] with a twofold molar excess of H3mps. The X-ray crystal structure shows that the trianionic ligand mps acts as a tridentate chelate via the doubly deprotonated amino nitrogen (an imide), the neutral imino nitrogen and the deprotonated phenolic oxygen. The six-coordinated complex cis-[Re(mps)Cl2(PPh3)2] was prepared by the reaction of trans-[ReOCl3(PPh3)2] with a twofold molar excess of H3mps in benzene. The X-ray crystal structure show that the mps ligand coordinates as a tridentate chelate via the doubly deprotonated 2-amino nitrogen, the neutral imino nitrogen and the phenolate oxygen. The imide and phenolate oxygen coordinate trans to each other in a distorted octahedral geometry, around the rhenium(V) centre, with the two chlorides in cis positions. A new oxofree rhenium(V) complex salt, [Re(bbd)2](ReO4) ( H2bbd = N-(2- Abstract I.N. Booysen Nelson Mandela Metropolitan University viii aminobenzylidene)benzene-1,2-diamine), has been synthesized and the chelates bbd are coordinated as dianionic tridentate N,N,N-donor diamidoimines. The rhenium(V) ion is centered in a distorted trigonal prism. The rhenium(I) compound fac-[Re(CO)3(daa)].Hpab.H2O (Hpab = N1,N2-(1,2- phenylene)bis(2-aminobenzamide); Hdaa = 2-amino-N-(2-aminophenyl)benzamide) was synthesized from the reaction of [Re(CO)5Br] with a two equivalents of Hpab in toluene. The monoanionic tridentate ligand daa was formed by the rhenium-mediated cleavage of an amido N-C bond of the potentially tetradentate ligand Hpab. Daa is coordinated as a diaminoamide via three nitrogen-donor atoms. The reaction of a twofold molar excess of H2amben (H2amben = N1,N2-bis(2-aminobenzylidene)ethane-1,2-diamine) with trans- [ReOBr3(PPh3)2] gave the oxorhenium(V) cationic complex [ReO(amben)]X (X = Br-, PF6 -). The Re(V) oxo-bridged compound, {μ-O}[ReO(omben)]2.H2O (H2omben = N1,N2- bis(2-hydroxybenzylidene)ethane-1,2-diamine) was isolated from the reaction of a 2:1 molar ratio of H2omben and trans-[ReO2(py)4]Cl in methanol. The seven-coordinate rhenium(III) complex cation [ReIII(dhp)(PPh3)2]+ was isolated as the [ReO4]- salt from the reaction of cis-[ReVO2I(PPh3)2] with 2,6-bis(2- hydroxyphenyliminomethyl)pyridine (H2dhp) in ethanol. In the complex fac- [Re(CO)3(H2dhp)Br], prepared from [Re(CO)5Br] and H2dhp in toluene, the H2dhp ligand acts as a neutral bidentate N,N-donor chelate. An equimolar ratio reaction of 2-aminobenzaldehyde and 2-(2-aminophenyl)-1- benzimidazole in methanol led to 2-(5,6-dihydrobenzimidazolo[1,2-c]-quinazolin-6- yl)aniline. In an attempt to explore the template formation of this class of ligand with rhenium, the reaction of salicylaldehyde and 2-(2-aminophenyl)-1-benzimidazole in ethanol which was followed by the addition of trans-[ReOBr3(PPh3)2] led to the formation of the salt, 6-(2-hydroxyphenyl)-5,6-dihydrobenzimidazolo[1,2-c]quinazolin- 12-ium bromide. The compound 6-(2-methylthiophenyl)-5,6-dihydrobenzimidazolo[1,2- c]quinazolin-12-ium was synthesized via the reaction of 2-aminobenzaldehyde and 2- methylthiobenzaldehyde in methanol.
- Full Text:
- Date Issued: 2009
Rhenium(V)-Imido complexes with potentially multidentate ligands containing the amino group
- Authors: Booysen, Irvin Noel
- Date: 2007
- Subjects: Rhenium , Ligands
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10385 , http://hdl.handle.net/10948/479 , Rhenium , Ligands
- Description: The complex trans-[Re(dab)Cl3(PPh3)2] (H2dab=1,2-diaminobenzene) was prepared from the reaction of trans-[ReOCl3(PPh3)2] with H2dab in ethanol. The ligand dab is coordinated to the rhenium(V) centre through a dianionic imido nitrogen only, in a distorted octahedral coordination geometry around the metal ion. The complex trans-[Re(ada)Cl3(PPh3)2] (H2ada=2-aminodiphenylamine) was prepared from the reaction of trans-[ReOCl3(PPh3)2] with H2ada in acetonitrile. The ligand ada is coordinated to the rhenium(V) centre through a dianionic imido nitrogen only, in a distorted octahedral coordination geometry around the metal ion. Surprisingly, the Re-Cl bond length trans to the Re=N bond is shorter than the two equatorial Re-Cl bond lengths. The reaction of equimolar quantities of cis-[ReO2I(PPh3)2] with 5,6-diamino-1,3- dimethyluracil (H2ddd) in acetonitrile led to the formation of [Re(ddd)(Hddd)I(PPh3)2](ReO4). The X-ray crystal structure shows that the ligand ddd is coordinated monodentately through the doubly deprotonated amino nitrogen and is therefore present as an imide. The chelate Hddd is coordinated bidentately via the neutral amino nitrogen, which is coordinated trans to the imido nitrogen, and the singly deprotonated amido nitrogen, trans to the iodide. The reaction of equimolar quantities of [NH4(ReO4)] with H2ddd in methanol under reflux conditions led to the isolation of [C12H12N6O4] as only product. The [ReO4]- ion is therefore instrumental in the formation of [C12H12N6O4], and since the product contains no rhenium in any oxidation state, the conclusion is that [ReO4]- catalyses the oxidative deamination of H2ddd. The X-ray crystal structure consists of two centrosymmetric, tricyclic rings, comprising a central pyrazine ring and two terminal pyrimidine rings. The reaction of a twofold molar excess of H2apb (H2apb=2-(2-aminophenyl)-1Hbenzimidazole) with trans-[ReO2(py)4]Cl in ethanol gave the green product of the formulation [ReO(Hapb)(apb)] in good yield. The rhenium atom lies in a distorted trigonal-bipyramidal environment. The two imidazole N(2) atoms lie in the apical positions trans to each other, with the oxo-oxygen and two amido N(1) atoms in the trigonal plane. The complex has C2-symmetry. The two amino groups are singly deprotonated and provide a negative charge each, so that they are coordinated as amides. The oxo group provides two negative charges. In order to obtain electroneutrality for the rhenium(V) complex, the two coordinated imidazole nitrogens provide one negative charge. The complex salt trans-[Re(mps)Cl(PPh3)2](ReO4) (H3mps=N-(2-amino-3- methylphenyl)salicylideneimine) was prepared by the reaction of trans- [ReOCl3(PPh3)2] with a twofold molar excess of H3mps. The X-ray crystal structure shows that the trianionic ligand mps acts as a tridentate chelate via the doubly deprotonated amino nitrogen (which is present in trans- [Re(mps)Cl(PPh3)2](ReO4) as an imide), the neutral imino nitrogen and the deprotonated phenolic oxygen. The [ReO4]- anion has approximately regular tetrahedral geometry. Two significant hydrogen bonds are formed between two of the perrhenyl oxygens and the water of crystallization. The six-coordinated complex cis-[Re(mps)Cl2(PPh3)2] was prepared by the reaction of trans-[ReOCl3(PPh3)2] with a twofold molar excess of H3mps in benzene. The Xray crystal structure shows that the mps ligand coordinates as a tridentate chelate via the doubly deprotonated 2-amino nitrogen, the neutral imino nitrogen and the phenolate oxygen. The imide and phenolate oxygen coordinate trans to each other in a distorted octahedral geometry around the rhenium(V) centre, with the two chlorides in cis positions.
- Full Text:
- Date Issued: 2007