| 1. |
- Abdelhamid, Muhammad, 1987, et al.
(författare)
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Electropolymerisation of N-Ethylanilinium Trifluoroacetate Ionic Liquid into Poly(N-Ethylaniline) and Control of its Morphology
- 2017
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Ingår i: Australian Journal of Chemistry. - 1445-0038 .- 0004-9425. ; 70:9, s. 985-989
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, the electropolymerisation of pre-synthesised N-ethylanilinium trifluoroacetate, a protic ionic liquid (PIL), was carried out. The PIL served as the monomer precursor, solvent, and supporting electrolyte for the polymerisation process, and no additional acid was required due to the protic nature of the PIL. Two different morphologies of the poly(N-ethylaniline) were achieved by using different electropolymerisation approaches and the resultant films were soluble in the PIL precursor as well as a wide range of organic solvents. The use of anilinium based PILs, as polymerisation precursors, promises a greener approach for the production of polyanilines, as well as highly processable polymers.
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| 2. |
- Acharya, Shravan, et al.
(författare)
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Rates of water exchange in 2,2'-bipyridine and 1,10-phenanthroline complexes of CoII and MnII
- 2017
-
Ingår i: Australian journal of chemistry (Print). - 0004-9425 .- 1445-0038. ; 70:6, s. 751-754
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Tidskriftsartikel (refereegranskat)abstract
- The rates and activation parameters of water exchange at pH 3.0 have been determined using variable temperature 17O NMR spectroscopy for four CoII complexes and one MnII complex: [Co(bpy)(H2O)4]2+, [Co(bpy)2 (H2O)2]2+, [Co(phen)-(H2O)4]2+, [Co(phen)2 (H2O)2]2+, and [Mn(bpy)(H2O)4]2+ (bpy = 2,2′-bipyridyl and phen = 1,10-phenanthroline). Substitution of aquo ligands with 1,10-phenanthroline or 2,2′-bipyridyl leads to an increase in the rate of exchange in the manganese complexes, from k298 (1.8 ± 0.1) × 107 s-1 for [Mn(H2O)6]2+ to (7.2 ± 0.3) × 107 s-1 for [Mn(phen)2 (H2O)2]2+, whereas the trends are more complex for the cobalt complexes. We have used the new data in conjunction with literature data for similar complexes to analyse the effect of M–OH2 distance and degree of substitution.
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| 3. |
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| 4. |
- Demir, Selvan, et al.
(författare)
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Pursuing the excision of carbon-centred hexanuclear scandium clusters {CSc6} from solid {CSc6}I12Sc
- 2022
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Ingår i: Australian journal of chemistry (Print). - : CSIRO Publishing. - 0004-9425 .- 1445-0038. ; 75:9, s. 523-531
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Tidskriftsartikel (refereegranskat)abstract
- A multi-gram synthetic route to black solid {CSc6}I12Sc (1) was developed which comprises the reaction of scandium triiodide, ScI3, with graphite and scandium metal at 850°C. Compound 1 dissolved in N,N-dimethylacetamide (DMA) to form a red solution. Results derived from 45Sc NMR and EPR spectroscopy indicated that a scandium cluster species exists in this solution along with a complex cation [Sc(DMA)6]3+. From these solutions crystals of [Sc(DMA)6]I3 (2) and a red oily product was isolated. Compound 2 was also prepared independently by dissolving ScI3 in DMA and two polymorphs, orthorhombic 2O and monoclinic 2M were crystallised. {CSc6}I12Sc (1) also dissolved in THF yielding a red solution which contains [ScI6]3− and a scandium cluster species, as analysed by 45Sc NMR and EPR spectroscopy.
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| 5. |
- Hao, X. J., et al.
(författare)
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Dendrimers as scaffolds for reversible addition fragmentation chain transfer (RAFT) agents : A route to star-shaped block copolymers
- 2005
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Ingår i: Australian journal of chemistry (Print). - 0004-9425 .- 1445-0038. ; 58:6, s. 483-491
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Tidskriftsartikel (refereegranskat)abstract
- Star-shaped block copolymers of styrene and n-butyl acrylate having three, six, and twelve pendent arms were successfully synthesized via reversible addition fragmentation chain transfer (RAFT) polymerization. Dendritic cores ( based on 1,1,1-trimethylolpropane) of generation 0, 1, and 2 have been functionalized with 3-benzylsulfanylthiocarbonylsulfanylpropionic ester groups and have subsequently been employed to mediate the polymerization of styrene and n-butyl acrylate to generate macro-star-RAFT agents as starting materials for chain extension. The chain extension of the macro-star-RAFT agents with either styrene or n-butyl acrylate by bulk free radical polymerization at 60 degrees C gives narrowly distributed polymer (final polydispersities close to 1.2) increasing linearly in molecular weight with increasing monomer-to-polymer conversion. However, with an increasing number of arms (i.e., when going from three- to twelve-armed star polymers), the chain extension becomes significantly less efficient. The molecular weight of the generated block copolymers was assessed using H-1 NMR spectroscopy as well as size exclusion chromatography calibrated with linear polystyrene standards. The hydrodynamic radius, R-h, of the star block copolymers as well as the precursor star polymers was determined in tetrahydrofuran by dynamic light scattering (90 degrees) at 25 degrees C. Interestingly, the observed R-h-M-n relationships indicate a stronger dependence of R-h on M-n for poly(butyl acrylate) stars than for the corresponding styrene polymers. R-h increases significantly when the macro-star-RAFT agent is chain extended with either styrene or n-butyl acrylate.
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| 6. |
- Iandolo, Beniamino, 1985, et al.
(författare)
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Enhanced Water Splitting on Thin-film Hematite Photoanodes Functionalized with Lithographically Fabricated Au Nanoparticles
- 2012
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Ingår i: Australian Journal of Chemistry. - : CSIRO Publishing. - 1445-0038 .- 0004-9425. ; 65:6, s. 633-637
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Tidskriftsartikel (refereegranskat)abstract
- Iron oxide in its crystalline form (hematite, alpha-Fe2O3) is an interesting candidate as a photoanode material for photoelectrochemical cells, in spite of its non-optimal optoelectronic properties. We report here on the beneficial effect of Au nanodisks on the photocurrent of alpha-Fe2O3. Photoanodes consisting of ultra-thin alpha-Fe2O3 films lithographically functionalized with Au nanodisks of varying size were characterized and tested. We found a significant increase in photocurrent for the functionalized samples. The highest increase in incident photon-to-electron conversion efficiency is roughly one order of magnitude compared with a reference sample without Au nanodisks and was found for incident light of 420 nm in wavelength. A detailed understanding of the phenomena underlying such an increase in efficiency is crucial to fully exploit the beneficial effect of the metallic nanostructures. This would contribute to make Fe2O3 more competitive in the race for the development of a commercially viable device for water splitting.
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| 7. |
- Lu, J., et al.
(författare)
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Structural, Spectroscopic, and Electrochemical Characterization of Semi-Conducting, Solvated [Pt(NH 3 ) 4 ](TCNQ) 2 ·(DMF) 2 and Non-Solvated [Pt(NH 3 ) 4 ](TCNQ) 2
- 2017
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Ingår i: Australian Journal of Chemistry. - 1445-0038 .- 0004-9425. ; 70:9, s. 997-1005
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Tidskriftsartikel (refereegranskat)abstract
- The demand for catalysts that are highly active and stable for electron-transfer reactions has been boosted by the discovery that [Pt(NH3)4](TCNQF4)2 (TCNQF4≤2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane) is an efficient catalyst. In this work, we prepare and characterize the two related [Pt(NH3)4] 2+ complexes, [Pt(NH3)4](TCNQ)2·(DMF)2 (1) and [Pt(NH3)4] (TCNQ)2 (2). Reaction of [Pt(NH3)4](NO3)2 with LiTCNQ in a mixed solvent (methanol/dimethylformamide, 4:1v/v) gives [Pt(NH3)4] (TCNQ)2·(DMF)2 (1), whereas the same reaction in water affords [Pt(NH3)4](TCNQ)2 (2). 2 has been previously reported. Both 1 and 2 have now been characterized by single-crystal X-ray crystallography, Fourier-transform (FT)IR, Raman and UV-vis spectroscopy, and electrochemistry. Structurally, in 1, the TCNQ1-anions form infinite stacks with a separation between adjacent anions within the stack alternating between 3.12 and 3.42Å. The solvated structure 1 differs from the non-solvated form 2 in that pairs of TCNQ1-anions are clearly displaced from each other. The conductivities of pressed pellets of 1 and 2 are both in the semi-conducting range at room temperature. 2 can be electrochemically synthesized by reduction of a TCNQ-modified electrode in contact with an aqueous solution of [Pt(NH3)4] (NO3)2 via a nucleation growth mechanism. Interestingly, we discovered that 1 and 2 are not catalysts for the ferricyanide and thiosulfate reaction. Li+ and tetraalkylammonium salts of TCNQ1-/2-and TCNQF41-/2-were tested for potential catalytic activity towards ferricyanide and thiosulfate. Only TCNQF41-/2-salts were active, suggesting that the dianion redox level needs to be accessible for efficient catalytic activity and explaining why 1 and 2 are not good catalysts. Importantly, the origin of the catalytic activity of the highly active [Pt(NH3)4](TCNQF4)2 catalyst is now understood, enabling other families of catalysts to be developed for important electron-transfer reactions.
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| 8. |
- Lü, X., et al.
(författare)
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Conformers, Properties of the Anticancer Drug Plocabulin, and its Binding Mechanism with p-Glycoprotein : DFT and MD Studies
- 2021
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Ingår i: Australian journal of chemistry (Print). - : CSIRO Publishing. - 0004-9425 .- 1445-0038. ; 74:7, s. 529-539
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Tidskriftsartikel (refereegranskat)abstract
- Plocabulin (PM060184) is a promising new anticancer drug as a microtubule inhibitor. The conformational structure and properties of plocabulin have been studied theoretically. The initial structure was screened by the B3LYP/3-21G∗ method, and then 32 unique conformations were further optimised with the B3LYP/6-311G∗ method. The single-point energies were determined at the M06-L/6-311G(2df,p) level. The UV excitation of the most stable plocabulin conformation in methanol was studied by the TD-CAM-B3LYP/6-311G(2df,p) method. High-quality human p-glycoprotein model was obtained through homology modelling. The binding interaction between p-glycoprotein and plocabulin was studied by docking and MD simulation. LEU65, TYR310, ILE340, THR945, PHE983, MET986, and GLN990 were found to be important amino acid residues in the interaction. From a certain perspective, the 'reverse exclusion' mechanism of plocabulin with p-glycoprotein was illustrated, and this mechanism provides theoretical guidance for the structural modification of plocabulin and for design of drug's to avoid p-glycoprotein-mediated drug resistance.
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| 9. |
- Magnuson, Ann, et al.
(författare)
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Molecular Chemistry for Solar Fuels : From Natural to Artificial Photosynthesis
- 2012
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Ingår i: Australian journal of chemistry (Print). - 0004-9425 .- 1445-0038. ; 65:6, s. 564-572
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Forskningsöversikt (refereegranskat)abstract
- The world needs new, environmentally friendly, and renewable fuels to exchange for fossil fuels. The fuel must be made from cheap, abundant, and renewable resources. The research area of solar fuels aims to meet this demand. This paper discusses why we need a solar fuel, and proposes solar energy as the major renewable energy source to feed from. The scientific field concerning artificial photosynthesis is expanding rapidly and most of the different scientific visions for solar fuels are briefly reviewed. Research strategies for the development of artificial photosynthesis to produce solar fuels are overviewed, with some critical concepts discussed in closer detail.
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| 10. |
- Messinger, Johannes
(författare)
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An Institutional Approach to Solar Fuels Research
- 2012
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Ingår i: Australian journal of chemistry (Print). - : CSIRO Publishing. - 0004-9425 .- 1445-0038. ; 65:6, s. 573-576
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Tidskriftsartikel (refereegranskat)abstract
- This account gives a brief overview of various directions in current solar fuels research. On that basis, the necessity for an interdisciplinary approach is argued, and an institutional way for promoting this development is presented using the example of the Chemistry Biology Centre (KBC) at Umeå University in Sweden.
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| 11. |
- Mizuno, Hiroyasu, et al.
(författare)
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Friction measurement between polyester fibres using the fibre probe SPM
- 2006
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Ingår i: Australian journal of chemistry (Print). - 0004-9425 .- 1445-0038. ; 59, s. 390-393
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Tidskriftsartikel (refereegranskat)abstract
- An SPM has been used to measure frictional interactions between two crossed fibres for the first time. The preparation of the surfaces is briefly described, but the crucial element is that the fibre attached to the AFM cantilever is glued parallel to the long axis. The fibres consist of polyester and frictional forces were measured both in air and solutions of cationic surfactant C(14)TAB. The friction coefficients reduce markedly with increasing concentration of surfactant which is ascribed to the formation of a boundary lubricating film between the surfaces. On removal of the solution, the subsequent friction coefficient in air was reduced by more than a factor of two compared to its value before immersion.
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| 12. |
- Nicholls, Ian A., et al.
(författare)
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Towards Peptide and Protein Recognition by Antibody Mimicking Synthetic Polymers – Background, State of the Art, and Future Outlook
- 2020
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Ingår i: Australian journal of chemistry (Print). - : CSIRO Publishing. - 0004-9425 .- 1445-0038. ; 73:4, s. 300-306
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Forskningsöversikt (refereegranskat)abstract
- Antibody–peptide/protein interactions are instrumental for many processes in the pharmaceutical and biotechnology industries and as tools for biomedical and biochemical research. The recent development of molecularly imprinted polymer nanoparticles displaying antibody-like recognition of peptides and proteins offers the possibility for substituting antibodies with these robust materials for applications where the structural integrity and function of antibodies is compromised by temperature, pH, solvent, etc. The background to the development of this class of antibody-mimicking material and the state-of-the-art in their synthesis and application is presented in this review.
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| 13. |
- Nordén, Bengt, 1945, et al.
(författare)
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X-POLARIZED AND Y-POLARIZED SPECTRA OF CHLOROPHYLL-A AND PHEOPHYTIN-A IN THE RED REGION - RESOLUTION ENHANCEMENT AND GAUSSIAN DECONVOLUTION
- 1992
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Ingår i: Australian Journal of Chemistry. - : CSIRO Publishing. - 1445-0038 .- 0004-9425. ; 45:10, s. 1559-1570
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Tidskriftsartikel (refereegranskat)abstract
- The red region of the X- and Y-polarized spectra obtained from the measurement of linear dichroism of chlorophyll a and pheophytin a oriented in a liquid crystal1 has been reexamined. A combination of resolution enhancement of the spectra involving their Fourier transformation and manipulation in the Fourier domain, and deconvolution into Gaussian bands on the wavenumber scale has produced results conforming to previous conclusions that place the origin of the Q(X) transition in chlorophyll a some 800-900 cm-1 to the blue relative to the origin of the Q(Y) transition. In pheophytin a, however, the separation between the Q(X) and Q(Y) bands is much larger, about 3600 cm-1. The results also confirm previous reports of an angle near 70-degrees between the transition moment directions of the Q(Y) transitions and the molecular X-axis for both chlorophyll a and pheophytin a. The resolved vibronic bands in the case of the Q(Y) transition of chlorophyll a, at least, have their counterparts in both solution spectra and high-resolution low-temperature fluorescence excitation spectra.
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| 14. |
- Percec, V., et al.
(författare)
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Helical porous protein mimics self-assembled from amphiphilic dendritic dipeptides
- 2005
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Ingår i: Australian journal of chemistry (Print). - 0004-9425 .- 1445-0038. ; 58:6, s. 472-482
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Tidskriftsartikel (refereegranskat)abstract
- This manuscript reports the synthesis and the self-assembly of (4-3,4,5-3,5)nG(2)-CH2-Boc-L-Tyr-L-Ala-OMe dendritic dipeptides (n = 12, 16). These dendritic dipeptides self-assemble both in solution and in solid states into helical porous supramolecular columns that mimic porous transmembrane proteins. These supramolecular assemblies provide also a new class of tubular supramolecular polymers.
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| 15. |
- Selan, Odi Th E, et al.
(författare)
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Impact of the 2Fe2P core geometry on the reduction chemistry of phosphido-bridged diiron hexacarbonyl compounds
- 2022
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Ingår i: Australian journal of chemistry (Print). - : CSIRO Publishing. - 0004-9425 .- 1445-0038. ; 75:9, s. 649-659
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Tidskriftsartikel (refereegranskat)abstract
- The effect of core geometry constraints of hydrogenase H-cluster analogues on reduction chemistry have been explored by a combination of structural, electrochemical and IR spectro-electrochemical (IR-SEC) studies. A series of phosphido-bridged diiron hexacarbonyl complexes, Fe-2(mu(2)-PPh2(CH2)(x)PPh2)(CO)(6), x = 2 (2P) and 4 (4P) and previously reported with x = 3 (3P) and the unlinked bis-diphenylphosphido (DP) analogues were investigated. The X-ray structures of the neutral complexes demonstrate the effect of the linking group on the Fe2P2 core geometry with P-Fe-Fe-P torsion angles of 95 (2P), 101 (3P), 108 (4P) and 109 degrees (DP) and a twisting of the Fe(CO)(3) fragments from an eclipsed geometry (2P, 3P and DP) for 4P. For all four compounds the primary reduction process involves two close-spaced one-electron reactions (E-1 and E-2) with a systematic trend to more negative reduction potentials with a shorter link between the bridging phosphorus atoms. This reflects the greater constraint that the bridging group places on the adoption of a planar 2Fe2P geometry. The sensitivity of the core geometry is greater for E-2 than E-1 and this impacts the stability of the monoanion with respect to disproportion (K-disp(298 K) = 0.02 (2P), 2.4 (3P) and 3540 (4P and DP)). 4P has a stable dianion and gives reversible cyclic voltammetry at 298 K and is quasi-reversible at 253 K, whereas the response of 2P is irreversible at 298 K, with two distinct daughter products, but becomes quasi-reversible at 253 K. IR-SEC measurements enabled elucidation of the spectra and time evolution of the reduction products. These results are consistent with a bimolecular reaction giving a distinct reduced product modelled as a dimeric, 4Fe species. The sensitivity of the reduction chemistry of the bridged diiron compounds underpins their utility as catalytic proton reduction catalysts and the systematic trends delineated in this investigation provide the framework for charting the path of their redox-coupled chemical reactions.
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| 16. |
- Sharma, A., et al.
(författare)
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Stability of Polymer Interlayer Modified ITO Electrodes for Organic Solar Cells
- 2016
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Ingår i: Australian Journal of Chemistry. - : CSIRO Publishing. - 1445-0038 .- 0004-9425. ; 69:7, s. 735-740
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Tidskriftsartikel (refereegranskat)abstract
- Indium-tin-oxide (ITO) electrode surfaces were modified using thin polymeric films of ethoxylated polyethylenimine (PEIE) and poly(3,3-([(9,9-dioctyl-9H,9H-[2,2-bifluorene]-9,9-diyl)bis(4,1-phenylen e)]bis(oxy))bis(N,N-dimethylpropan-1-amine)) (PFPA-1) to investigate the resultant work function and its stability in ambient atmosphere. Both PEIE and PFPA-1 were found to significantly reduce the ITO work function, as a result of a surface dipole at the ITO-polymer interface. After aging for two weeks in ambient air atmosphere, the N-side groups and OH groups in PEIE-modified ITO were found to realign themselves away from the polymer surface, resulting in an orientation more parallel to the surface normal and thus in an increase in work function from 3.5 to 3.8eV. The work function of PFPA-1-modified ITO was found to increase from 3.65 to 4.1eV after two weeks of aging in air due to a complete re-orientation of the polar side chains away from the surface, aligning the dipoles more parallel to the surface normal. In both PEIE and PFPA-1 samples, the hydrophobic aliphatic carbon was found to dominate the polymer surface, after aging.
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| 17. |
- Stokes, Francesca A., et al.
(författare)
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Towards the Synthesis of Guanidinate- and Amidinate-Bridged Dimers of Mn and Ni
- 2014
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Ingår i: Australian journal of chemistry (Print). - 0004-9425 .- 1445-0038. ; 67:7, s. 1081-1087
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Tidskriftsartikel (refereegranskat)abstract
- Reactions of Cp2M (Cp = cyclopentadienyl, M = Mn, Ni) with lithium amidinates and guanidinates are reported. The highly oxophilic nature of Mn leads to the isolation of the interstitial oxide Mn4O(MeN - CH - NMe)(6) (4) in preference to the intended paddle-wheel homodimer Mn-2(MeN - CH - NMe)(4) when employing the sterically uncongested amidinate [MeN - CH - NMe](-) ligand. In contrast, an analogous reaction using Cp2Ni yielded Ni-2(MeN - CH - NMe)(4) (5). The use of monoprotic guanidinate ligands also gave contrasting results for Mn and Ni. In the first case, the highly unusual spirocycle Mn{mu-NC(NMe2)(2)}(4)Li-2 center dot 3THF (6) was produced in low yield. For M = Ni, use of the [hpp](-) (1,3,4,6,7,8hexahydro-2H-pyrimido[1,2-alpha] pyrimidinate) ligand gives results comparable with the synthesis of 5, with Ni-2(hpp) 4 (7) isolated. In contrast to recent data obtained using Cp2Cr, the guanidinate ligands do not sequester coformed CpLi. Density functional theory analysis corroborates the view that the intermetal distance in each of the reported dinickel paddle-wheel complexes (2.4846(8) and 2.3753(5) angstrom in 5 and 7 respectively) is defined by the geometric parameters of the bidentate ligands and that intermetal bonding is not present.
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| 18. |
- Zhan, Xuejia, et al.
(författare)
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A Label-Free Electrochemical Aptasensor for the Rapid Detection of Tetracycline Based on Ordered Mesoporous Carbon-Fe3O4
- 2018
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Ingår i: Australian journal of chemistry (Print). - : CSIRO Publishing. - 0004-9425 .- 1445-0038. ; 71:2-3, s. 170-176
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Tidskriftsartikel (refereegranskat)abstract
- A novel aptasensor based on a tetracycline (TET) aptamer immobilized by physical adsorption on an ordered mesoporous carbon-Fe3O4 (OMC-Fe3O4)-modified screen-printed electrode surface was successfully fabricated. OMC-Fe3O4 was characterized by scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The modification procedure of the aptasensor was characterized by cyclic voltammetry. Interaction between the TET aptamer and target was determined by differential pulse voltammetry. Under optimal conditions, the proposed aptasensor exhibited good electrochemical sensitivity to TET in a concentration range of 5 nM to 10 μM, with a detection limit of 0.8 nM (S/N =3D 3). This aptasensor exhibited satisfactory specificity, reproducibility, and stability.
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| 19. |
- Hughes, Joseph L, et al.
(författare)
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The Native Reaction Centre of Photosystem II: A New Paradigm for P680
- 2004
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Ingår i: Australian Journal of Chemistry. - 0004-9425. ; 57:12, s. 1179-1183
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Tidskriftsartikel (refereegranskat)abstract
- Low-temperature spectra of fully active (oxygen-evolving) Photosystem II (PSII) cores prepared from spinach exhibit well developed structure. Spectra of isolated sub-fragments of PSII cores establish that the native reaction centre is better structured and red-shifted compared to the isolated reaction centre. Laser illumination of PSII cores leads to efficient and deep spectral hole-burning. Measurements of homogeneous hole-widths establish excited-state lifetimes in the 40–300 ps range. The high hole-burning efficiency is attributed to charge separation of P680 in native PSII that follows reaction-centre excitation via ‘slow transfer’ states in the inner light-harvesting assemblies CP43 and CP47. The ‘slow transfer’ state in CP47 and that in CP43 can be distinguished in the hole-burning action spectrum and high-resolution hole-burning spectra. An important observation is that 685–700 nm illumination gives rise to efficient P680 charge separation, as established by QA− formation. This leads to a new paradigm for P680. The charge-separating state has surprisingly weak absorption and extends to 700 nm.
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| 20. |
- Lawrence, M. A. W., et al.
(författare)
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Synthesis and Structure of a Novel Substituted Benzothiazolyl-N-phenyl-2-pyridinecarbothioamide; Kinetics of Formation and Electrochemistry of Two of its Palladium Pincer Complexes
- 2015
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Ingår i: Australian Journal of Chemistry. - : CSIRO Publishing. - 0004-9425. ; 68:5, s. 731-741
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Tidskriftsartikel (refereegranskat)abstract
- The synthesis and crystal structures of bis-N-(2,5-dimethoxyphenyl)pyridine-2,6-dicarbothioamide (dicarbothioamide I) and 6-(4,7-dimethoxy-2-benzothiazolyl)-N-(2,5-dimethoxyphenyl)-2-pyridinecar bothioamide (L-1) as well as the syntheses of the palladium(ii) chloride and acetate pincer complexes are reported. The stability constant for the palladium complex formation at 25 degrees C was found to be (2.04 +/- 0.26)x10(4)dm(3)mol(-1) and (2.30 +/- 0.19)x10(4)dm(3)mol(-1) with H-f=8 +/- 1kJmol(-1), S-f=108 +/- 10JK(-1)mol(-1), and H-f=17 +/- 4kJmol(-1) and S-f=140 +/- 20JK(-1)mol(-1) for the PdClL1 and Pd(OAc)L-1, respectively. The kinetics of formation of the palladium(ii) complexes were investigated and the mechanism is proposed to be associative in nature (H-1(double dagger)=34 +/- 2kJmol(-1) and S-1(double dagger)=-113 +/- 8JK(-1)mol(-1), and H-1(double dagger)=37 +/- 3kJmol(-1) and S-1(double dagger)=-100 +/- 8JK(-1)mol(-1) for the PdClL1 and Pd(OAc)L-1 species, respectively). The electrochemical measurements of the acetonitrile solutions revealed irreversible electron transfers consistent with the electrochemical decomposition of the ligand and its coordination complexes.
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| 21. |
- Powell, KJ, et al.
(författare)
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Chemical speciation of Hg(II) with environmental inorganic ligands
- 2004
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Ingår i: AUSTRALIAN JOURNAL OF CHEMISTRY. - 0004-9425. ; 57:10, s. 993-1000
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Tidskriftsartikel (refereegranskat)abstract
- Complex formation between Hg(II) and the common environmental ligands Cl-, OH-, CO32-, SO42-, and PO43- can have profound effects on Hg(II) speciation in naturalwaters with low concentrations of organic matter. Hg(II) is labile, so its distribution among these inorganic ligands can be estimated by numerical modelling if reliable values for the relevant stability constants are available. A summary of critically reviewed constants and related thermodynamic data is presented. Recommended values of log(10) beta(p,q,r)(o) and the associated reaction enthalpies, Delta(r)H(m)(o), valid at I-m = 0 mol kg(-1) and 25degreesC, along with the equations and specific ion interaction coefficients required to calculate log(10) beta(p,q,r) values at higher ionic strengths and other temperatures are also presented. Under typical environmental conditions Hg(II) speciation is dominated by the reactions Hg2+ + 2Cl(-) reversible arrow HgCl2(aq) (log(10) beta(2)(o) = 14.00 +/- 0.07), Hg2+ + Cl- + H2O reversible arrow Hg(OH) Cl(aq) + H+ (log(10) beta(o) = 4.27 +/- 0.35), and Hg2+ + 2H(2)O reversible arrow Hg(OH)(2(aq)) + 2H(+) (log(10)* beta(2)(o) =- 5.98 +/- 0.06).
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