https://nova.newcastle.edu.au/vital/access/ /manager/Index ${session.getAttribute("locale")} 5 Carbonic anhydrase activity of dinuclear Cu<sup>II</sup> complexes with patellamide model ligands https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:20991 cat up to 7.3 × 10³ s⁻¹ (uncatalyzed: 3.7 × 10⁻² s⁻¹; enzyme-catalyzed: 2 × 105–1.4 × 106 s⁻¹) and a turnover number (TON) of at least 1700, limited only by the experimental conditions used. So far, no copper-based natural carbonic anhydrases are known, no faster model systems have been described and the biological role of the patellamide macrocycles is so far unknown. The observed CO₂ hydration rates depend on the configuration of the isopropyl side chains of the pseudo-octapeptide scaffold, and the naturally observed R*,S*,R*,S* geometry is shown to lead to more efficient catalysts than the S*,S*,S*,S* isomers. The catalytic efficiency also depends on the heterocyclic donor groups of the pseudo-octapeptides. Interestingly, the dicopper(II) complex of the ligand with four imidazole groups is a more efficient catalyst than that of the close analogue of ascidiacyclamide with two thiazole and two oxazoline rings. The experimental observations indicate that the nucleophilic attack of a CuII-coordinated hydroxide at the CO₂ carbon center is rate determining, i.e. formation of the catalyst-CO₂ adduct and release of carbonate/bicarbonate are relatively fast processes.]]> Sat 24 Mar 2018 07:50:41 AEDT ]]> Stable five- and six-coordinate cobalt (III) complexes with a pentadentate bispidine ligand https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:5582 Sat 24 Mar 2018 07:49:26 AEDT ]]> Stability constants: a new twist in transition metal bispidine chemistry https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:3189 Sat 24 Mar 2018 07:21:56 AEDT ]]> Synthesis and characterization of copper complexes with a series of tripodal amine ligands https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:47588 4-p33) crystallized as a dinuclear complex, [Cu(Me4-p3H3)OH]2(ClO4)4, that could be structurally characterized. Interestingly, it turned out that in crystalline form the two bridging hydroxide ions were intact while two of the amine arms of the two ligands were protonated. DFT calculations were performed to get a better understanding of the behavior of this complex system in solution. Further protonation of two more amine ligand arms in solution was possible, still keeping the bridging hydroxide ions in place in the solid state. A related copper(II) complex system could be crystallized that contained a coordinated carbonate anion together with a protonated amine arm.]]> Mon 23 Jan 2023 14:42:36 AEDT ]]>