title: The Chemistry of Cycloaurated Complexes

authors: Kilpin, Kelly Joan

subjects: gold

abstract: New cycloaurated complexes have been synthesised and characterised. The biological and catalytic activity (in the addition of 2-methylfuran to methyl vinyl ketone) of selected complexes was evaluated. New complexes reported in this thesis where fully characterised by NMR (¹H, ¹³C and ³¹P when appropriate) and IR spectroscopy, ESI-mass spectrometry and elemental analysis.

The simple cycloaurated iminophosphoranes (2-AuCl₂C₆H₄)Ph₂P=N-R (R = (R,S)-CHMePh, (S)-CHMePh, p-C₆H₄F or But) were synthesised by the reaction of the appropriate ortho-mercurated compound with [Me₄N][AuCl₄] and [Me₄N]Cl in acetonitrile; the complex (2-AuCl₂C₆H₄)Ph₂P=N-(S)-CHMePh was structurally characterised. The cis chloride ligands on the complexes were replaced by chelating dianionic ligands such as thiosalicylate and catecholate - the resulting bis-metallacyclic complexes have a better anti-tumour activity (against P388 murine leukemia cells) than the parent dichlorides. The nitrogen-gold coordinate bond is relatively robust and is not cleaved by cyanide or dithiocarbamate ligands. The reaction of (2-AuCl₂C₆H₄)Ph₂P=N-Ph with PPh₃ results in substitution of the chloride ligand trans to the nitrogen (shown by an X-ray crystal structure). Both the endo ((2-AuCl₂C₆H₄)Ph₂P=NC(O)Ph) and exo ((2-AuCl₂C₆H₄)C(O)N=PPh₃) cycloaurated isomers of the stabilised iminophosphorane Ph₃P=NC(O)Ph were synthesised and structurally characterised.

Cycloaurated Ph₃P=S and Ph₃P=Se were synthesised by a transmetallation reaction from 2-Hg[(C₆H₄)P(E)Ph₂]₂ (E = S or Se). The synthesis of cycloaurated Ph₃P=O by an analogous method was unsuccessful. PhP(S)(NEt₂)₂ was also cycloaurated via a transmetallation reaction. X-ray crystallography confirmed the sulfur (not the nitrogen) was coordinated to the gold centre. The complexes show a similar stability and reactivity to the C,N cycloaurated species - the cis chloride ligands can be replaced by the chelating thiosalicylate ligand. Again the bis-metallacyclic species showed better biological activity than the parent dichloride. 

The direct reaction of the 2-pyridyl sulfonamide ligands 2-(C₅H₅N)CH₂NHSO₂R (R = p-tolyl, Ph or Me), 2-(C₅H₅N)CH₂CH₂NHSO₂R (R = p-tolyl or Ph) or 8-(p-tosylamino)quinoline with refluxing aqueous H[AuCl₄] gave N,N' coordinated complexes containing a five- or six-membered cycloaurated ring. The cycloaurated complexes derived from the ligands 2-(C₅H₅N)CH₂NHSO₂Me and 8-(p-tosylamino)quinoline were structurally characterised. The cycloaurated N,N' systems were not as stable as the C,N systems - reaction with reducing agents led to reduction of Au(III) to Au(I) and elemental gold. 

The 2-pyridine thiocarboxamide ligands 2-(C₅H₅N)C(S)NHR (R= p-tolyl, CH₂Ph, Me, p-C₆H₅OMe) also underwent direct cycloauration upon reaction with H[AuCl₄]. Coordination via the pyridyl nitrogen and sulfur atom was confirmed by an X-ray crystal structure of cycloaurated 2-(C₅H₅N)C(S)NHCH₂Ph. The N,S cycloaurated systems show poor stability in solution and decompose relatively quickly so applications are limited. The ligand with a 2 pyridyl substituent reacted with H[AuCl₄] in a different manner. Instead of cycloauration, the ligand was oxidised and an internal cyclisation occurred to give a 1,2,4-thiadiazolo[2,3-a]pyridinium heterocyclic ring. 

The reaction of the cycloaurated dichloride complexes (2-benzylpyridine)AuCl₂ and (2-AuCl₂C₆H₄)Ph₂P=N-Ph with the tripodal Kläui ligands (Na[(C₅H₅)Co{P(O)R₂}₃], R = OMe or OEt) and Tl[BF₄] resulted in the formation of cationic gold(III) salts. In the solid state the Kläui ligand is strongly coordinated through two of the three oxygen atoms, and weakly by the third, giving the gold a distorted square pyramidal geometry. In solution there is rapid interchange between the coordinated and non-coordinated oxygen atoms.

text: The Chemistry of Cycloaurated Complexes New cycloaurated complexes have been synthesised and characterised. The biological and catalytic activity (in the addition of 2-methylfuran to methyl vinyl ketone) of selected complexes was evaluated. New complexes reported in this thesis where fully characterised by NMR (¹H, ¹³C and ³¹P when appropriate) and IR spectroscopy, ESI-mass spectrometry and elemental analysis.

The simple cycloaurated iminophosphoranes (2-AuCl₂C₆H₄)Ph₂P=N-R (R = (R,S)-CHMePh, (S)-CHMePh, p-C₆H₄F or But) were synthesised by the reaction of the appropriate ortho-mercurated compound with [Me₄N][AuCl₄] and [Me₄N]Cl in acetonitrile; the complex (2-AuCl₂C₆H₄)Ph₂P=N-(S)-CHMePh was structurally characterised. The cis chloride ligands on the complexes were replaced by chelating dianionic ligands such as thiosalicylate and catecholate - the resulting bis-metallacyclic complexes have a better anti-tumour activity (against P388 murine leukemia cells) than the parent dichlorides. The nitrogen-gold coordinate bond is relatively robust and is not cleaved by cyanide or dithiocarbamate ligands. The reaction of (2-AuCl₂C₆H₄)Ph₂P=N-Ph with PPh₃ results in substitution of the chloride ligand trans to the nitrogen (shown by an X-ray crystal structure). Both the endo ((2-AuCl₂C₆H₄)Ph₂P=NC(O)Ph) and exo ((2-AuCl₂C₆H₄)C(O)N=PPh₃) cycloaurated isomers of the stabilised iminophosphorane Ph₃P=NC(O)Ph were synthesised and structurally characterised.

Cycloaurated Ph₃P=S and Ph₃P=Se were synthesised by a transmetallation reaction from 2-Hg[(C₆H₄)P(E)Ph₂]₂ (E = S or Se). The synthesis of cycloaurated Ph₃P=O by an analogous method was unsuccessful. PhP(S)(NEt₂)₂ was also cycloaurated via a transmetallation reaction. X-ray crystallography confirmed the sulfur (not the nitrogen) was coordinated to the gold centre. The complexes show a similar stability and reactivity to the C,N cycloaurated species - the cis chloride ligands can be replaced by the chelating thiosalicylate ligand. Again the bis-metallacyclic species showed better biological activity than the parent dichloride. 

The direct reaction of the 2-pyridyl sulfonamide ligands 2-(C₅H₅N)CH₂NHSO₂R (R = p-tolyl, Ph or Me), 2-(C₅H₅N)CH₂CH₂NHSO₂R (R = p-tolyl or Ph) or 8-(p-tosylamino)quinoline with refluxing aqueous H[AuCl₄] gave N,N' coordinated complexes containing a five- or six-membered cycloaurated ring. The cycloaurated complexes derived from the ligands 2-(C₅H₅N)CH₂NHSO₂Me and 8-(p-tosylamino)quinoline were structurally characterised. The cycloaurated N,N' systems were not as stable as the C,N systems - reaction with reducing agents led to reduction of Au(III) to Au(I) and elemental gold. 

The 2-pyridine thiocarboxamide ligands 2-(C₅H₅N)C(S)NHR (R= p-tolyl, CH₂Ph, Me, p-C₆H₅OMe) also underwent direct cycloauration upon reaction with H[AuCl₄]. Coordination via the pyridyl nitrogen and sulfur atom was confirmed by an X-ray crystal structure of cycloaurated 2-(C₅H₅N)C(S)NHCH₂Ph. The N,S cycloaurated systems show poor stability in solution and decompose relatively quickly so applications are limited. The ligand with a 2 pyridyl substituent reacted with H[AuCl₄] in a different manner. Instead of cycloauration, the ligand was oxidised and an internal cyclisation occurred to give a 1,2,4-thiadiazolo[2,3-a]pyridinium heterocyclic ring. 

The reaction of the cycloaurated dichloride complexes (2-benzylpyridine)AuCl₂ and (2-AuCl₂C₆H₄)Ph₂P=N-Ph with the tripodal Kläui ligands (Na[(C₅H₅)Co{P(O)R₂}₃], R = OMe or OEt) and Tl[BF₄] resulted in the formation of cationic gold(III) salts. In the solid state the Kläui ligand is strongly coordinated through two of the three oxygen atoms, and weakly by the third, giving the gold a distorted square pyramidal geometry. In solution there is rapid interchange between the coordinated and non-coordinated oxygen atoms.

year: 2009

title: Mechanical properties of thermoplastic protein from bloodmeal and polyester blends

authors: Marsilla, K. I. Ku

subjects: blending

abstract: Blends of bloodmeal-based thermoplastic (NTP) and polybutylene succinate (PBS) were prepared to study the effect of compatibilization on mechanical properties. The Taguchi method was used for experimental design and the results were analysed in terms of signal-to-noise (S/N) ratios using analysis of variance (ANOVA). Between 5 and 10 wt.-% of either poly-2-ethyl-2-oxazoline (PEOX) and poly [(phenyl isocyanate)-co-formaldehyde] (pMDI) were used as compatibilizers in blends of 20–100% NTP. The tensile strength of the blends depended on the type of compatibilizer used while for elongation at break and modulus, NTP content had the largest influence. Compatibilizing efficiency was more pronounced at higher NTP content. The blend's morphology showed a smaller particle size for blends at optimal tensile properties while plastic deformation was observed for samples where elongation at break was optimal.

text: Mechanical properties of thermoplastic protein from bloodmeal and polyester blends Blends of bloodmeal-based thermoplastic (NTP) and polybutylene succinate (PBS) were prepared to study the effect of compatibilization on mechanical properties. The Taguchi method was used for experimental design and the results were analysed in terms of signal-to-noise (S/N) ratios using analysis of variance (ANOVA). Between 5 and 10 wt.-% of either poly-2-ethyl-2-oxazoline (PEOX) and poly [(phenyl isocyanate)-co-formaldehyde] (pMDI) were used as compatibilizers in blends of 20–100% NTP. The tensile strength of the blends depended on the type of compatibilizer used while for elongation at break and modulus, NTP content had the largest influence. Compatibilizing efficiency was more pronounced at higher NTP content. The blend's morphology showed a smaller particle size for blends at optimal tensile properties while plastic deformation was observed for samples where elongation at break was optimal.

year: 2014

title: He pakiriha

authors: Temara, Pou

subjects: Tikanga

abstract: Kua tae ki te wā hai kōrero i ētahi tikanga marae, ētahi tikanga kawa e kawa ana ki tā te mātanga titiro. Tērā ētahi tikanga e whakamahia ana e ngā kaumātua o nāianei e uru atu ana ki te pae o rorirori, ka mutu, e ai ki tā ngā kaumātua nei, ko te mutunga mai o te tika ā rātau i whakatau ai. Nā hei whakarāpopoto i te whakaaro whānui, i ētahi wā kāore ko te mea e tika ana ki ō tātau whakaaro te huarahi pai. Ko tā te tikanga he kimi i te huarahi e tika ana, kia kore ai e whara ngā whakaaro o te tangata. Ko te tikanga ehara i te mea i whakairotia ki te kōhatu, engari e taea ana te neke i ngā pae o te tikanga kia pai ai te whakahaere a te tangata i āna mahi, kia tau ai te rangimārie, kia mau tonu ai te mana o te tangata. E whakapae ana ahau e kūmea ana e ētahi kaumātua ētahi tikanga kia hāngai ki tā rātau i whakaaro ai kai te tika, kai te hē rānei. Mā ētahi tauira e mārama ai te kaipānui ki te kaupapa me te whakaaro o te kaituhi.

text: He pakiriha Kua tae ki te wā hai kōrero i ētahi tikanga marae, ētahi tikanga kawa e kawa ana ki tā te mātanga titiro. Tērā ētahi tikanga e whakamahia ana e ngā kaumātua o nāianei e uru atu ana ki te pae o rorirori, ka mutu, e ai ki tā ngā kaumātua nei, ko te mutunga mai o te tika ā rātau i whakatau ai. Nā hei whakarāpopoto i te whakaaro whānui, i ētahi wā kāore ko te mea e tika ana ki ō tātau whakaaro te huarahi pai. Ko tā te tikanga he kimi i te huarahi e tika ana, kia kore ai e whara ngā whakaaro o te tangata. Ko te tikanga ehara i te mea i whakairotia ki te kōhatu, engari e taea ana te neke i ngā pae o te tikanga kia pai ai te whakahaere a te tangata i āna mahi, kia tau ai te rangimārie, kia mau tonu ai te mana o te tangata. E whakapae ana ahau e kūmea ana e ētahi kaumātua ētahi tikanga kia hāngai ki tā rātau i whakaaro ai kai te tika, kai te hē rānei. Mā ētahi tauira e mārama ai te kaipānui ki te kaupapa me te whakaaro o te kaituhi.

year: 2017