The stabilities and formation kinetics of some macrocycles with copper(II): crystal structures of some pendant arm macrocycles

Özay, Hava; Βaran, Yakup; Miyamae, Hiroshi

doi:10.1080/00958972.2011.574128

Cited by 6 publications

(2 citation statements)

References 26 publications

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“…The tetravalent macrocyclic ligand, cyclam, was chosen for its small size (relative to other known cobalt-binding ligands) and strong affinity to the metal (logK = 12.7 for Co(II)-cyclam) [41,42]. Macrocyclic ligands are known to provide higher kinetic stability to coordinating metals in comparison to their acyclic counterparts [43]. …”

Section: Resultsmentioning

confidence: 99%

Cobalt-based paramagnetic probe to study RNA-protein interactions by NMR

Seebald

DeMott

Ranganathan

et al. 2017

Journal of Inorganic Biochemistry

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Paramagnetic resonance enhancement (PRE) is an NMR technique that allows studying three-dimensional structures of RNA-protein complexes in solution. RNA strands are typically spin labeled using nitroxide reagents, which provide minimal perturbation to the native structure. The current work describes an alternative approach, which is based on a Co2+-based probe that can be covalently attached to RNA in the vicinity of the protein’s binding site using ‘click’ chemistry. Similar to nitroxide spin labels, the transition metal based probe is capable of attenuating NMR signal intensities from protein residues localized <40 Å away. The extent of attenuation is related to the probe’s distance, thus allowing for construction of the protein’s contact surface map. This new paradigm has been applied to study binding of HIV-1 nucleocapsid protein 7, NCp7, to a model RNA pentanucleotide.

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Section: Resultsmentioning

confidence: 99%

Cobalt-based paramagnetic probe to study RNA-protein interactions by NMR

Seebald

DeMott

Ranganathan

et al. 2017

Journal of Inorganic Biochemistry

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“…Tetraaza/oxatriaza macrocycles 6-15, as in 89 They form very stable 1:1 complexes and display inertness to demetallation due to the macrocyclic effect. 76,89,[160][161][162][163][164] The macrocyclic effect is the increased stability of complexes between metal ions and macrocyclic ligands, compared to their open-chain counterparts. For instance, the Log(KCu(II)L) values for cyclen (11) and its open-chain counterpart, triethylenetetramine, are 23.3 and 20.0, respectively.…”

Section: Tetraaza/oxatriaza Macrocycles: Cyclenmentioning

confidence: 99%

Selective Metal Coordination in Antifouling Coatings

Robinson¹

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<p>Marine biofouling is the accumulation of biological material (e.g. microorganisms, soft- and hard-fouling organisms) on the surface of an object submerged in seawater, and it remains a worldwide problem for shipping industries. The fouling of ship hulls results in a reduction of speed and manoeuvrability due to frictional drag, as well as increased fuel consumption and accelerated corrosion, and the exorbitant expenses and losses of efficiency attributed to biofouling have prompted the development of antifouling coatings. Current antifouling paints use copper as a biocidal agent, but copper-based paints are increasingly being banned due to environmental concerns about the non-target effects of leached copper. This project aims to circumvent these concerns and tightening regulations via a revolutionary concept: the development of marine antifouling paints that incorporate Cu(II)-selective ligands to draw the biocidal ingredient (i.e. Cu(II)) from seawater. A multistage strategy emerged for the development of this technology. First, criteria were established for the project’s ideal ligand, and ligands were synthesised or selected based on these criteria. Second, the ligands were incorporated in coatings through covalent modification of the paint binder or additives. Third, methodology was developed and implemented to test each coating’s ability to coordinate and retain Cu(II), as well as its subsequent ability to prevent microfouling by marine bacteria. The suitability of two ligand classes was assessed: acylhydrazones and tetraaza macrocycles, specifically cyclen. Unlike the acylhydrazones, cyclen met the established criteria and was initially evaluated as a curing agent and/or surface-modifier in a two-pack epoxy system with resin Epikote™ 235. However, the Cu(II)-loading by these coatings was relatively low, being at most ~0.05% w/w, and the modification of silica, a common paint additive, with cyclen was explored as an alternative formulation route. The method for the functionalisation of silica with cyclen was optimised, and the maximum Cu(II)-loading achieved by the product was 2.60% w/w. The cyclen-functionalised silica was incorporated on the surface of an epoxy coating, and a bacterial adherence assay was developed to assess the cellular attachment of marine bacterium Vibrio harveyi to this coating, which was found to be undeterred. Yet, the development of the strategy and testing methodology by which the project’s goals may be achieved provides a solid foundation for future work.</p>

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