Transition Metal Complexes of Some Azamacrocycles and Their Use in Molecular Recognition

Geduhn, Jens; Walenzyk, Thomas; König, Burkhard

doi:10.2174/157017907782408770

Cited by 36 publications

(30 citation statements)

References 69 publications

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“…A green complex was isolated after reaction of 4,7-bis(2-hydroxyethyl)-1-thia-4,7diazacyclononane ( Figure 37 Fitting of the variable temperature susceptibility data (4 -300 K) with the Bleaney-Bowers [196] equation indicated that the two copper(II) sites were non-interacting (2J = -0.001 cm -1 ) [75]. EPR spectroscopy was consistent with a single paramagnetic d 9 The IR spectrum shows two bands at 2246 cm -1 and 2150 cm -1 ; the peak at lower frequency shifted to lower energy on 13 Figure 47) [197]. The crystal structure revealed a distorted octahedral geometry around the metal ion with the cyclononane macrocycle occupying one face of the metal.…”

Section: Copper(ii) Silver and Gold(iii)mentioning

confidence: 95%

“…The ligand showed a stronger "OFF-ON" CHEF effect in the Zn(II) complexes than in the Cd(II) complexes [197]. The The complex displays a five-line 13 and a trigonal prism [198]. The N 2 S planes of the respective ligands are rotated by 89° from the eclipsed positions with the coordination polyhedron expanded in the direction orthogonal to the ligand planes [198].…”

Section: Copper(ii) Silver and Gold(iii)mentioning

confidence: 98%

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Cyclononanes: The extensive chemistry of fundamentally simple ligands

Gahan

2016

Coordination Chemistry Reviews

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The cyclononane ligands are fundamental examples of the macrocyclic ligand. With three donor atoms in a nine-membered ring they represent the simplest of the macrocyclic class. However, this simplicity is deceptive, for within this class the variations are extensive and perhaps hitherto unrecognized. As well as the relatively familiar 1,4,7-triaza-([9]aneN 3) and 1,4,7-trithia-([9]aneS 3) cyclononanes whole families of cyclononane ligands are known with thioether/nitrogen, nitrogen/oxygen, selenium, tellurium as well as phosphorus and arsenic donors. The chemistry of some of these ligands, for example [9]aneN 2 S, [9]aneNS 2 and [9]aneN 2 O has been reported extensively, and some examples have simply been reported as having been synthesised (for example [9]aneO 2 S and [9]aneO 2 Se) with little other information. This review attempts to introduce the extensive chemistry of what are fundamentally the simplest examples of macrocyclic ligands. 1. Highlights Review of current trends in cyclononane chemistry Diversity of donor groups and transition metal chemistry complexes which arise Significant new synthetic chemistry Significant advances in the applications of cyclononane ligands

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Section: Copper(ii) Silver and Gold(iii)mentioning

confidence: 95%

Section: Copper(ii) Silver and Gold(iii)mentioning

confidence: 98%

Cyclononanes: The extensive chemistry of fundamentally simple ligands

Gahan

2016

Coordination Chemistry Reviews

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“…[15] Transition metal complexes have much to offer in the realm of the molecular machine, and to supramolecular chemistry more generally. [16][17][18][19][20][21] Metal complexes of azamacrocycle ligands have been used for molecular recognition, [22,23] in av ariety of biomimetic systems, [24][25][26] and as molecular switches. [27][28][29][30][31][32][33][34][35] The terms "scorpiand" and more recently "scorpionand" have been appliedt od escribe macrocycles bearing am ovable pendant arm whose coordination properties may be alteredb ye xternal input (based on the likeness to an 'aggressive molecular "tail" that "stings"t he chelated metal centre from the top').…”

Section: Introductionmentioning

confidence: 99%

Molecular Switches for any pH: A Systematic Study of the Versatile Coordination Behaviour of Cyclam Scorpionands

Lau

Clegg

Price

et al. 2017

Chemistry A European J

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Molecular switches have many potential applications in nanoscience and biomedicine. Transition metal complexes that can be switched from an inert, unreactive state to a catalytically active one by a simple change in conditions (e.g. pH shift) or by binding to a specific biomolecular target-so-called target-activated metal complexes (TAMCs)-hold particular allure as a means of harnessing the potent but at times indiscriminate reactivity of metal-based drugs. Towards this goal, we have prepared a series of ten structurally related ligands, each of which bears a different pendant side-arm functional group appended to a common macrocyclic core, along with copper(II) and nickel(II) complexes of these cyclam-based "molecular scorpionands". X-ray crystal structures reveal a variety of binding modes between pendant side-arm and metal centre that depend on the constituent donor atoms. To investigate the switchability of side-arm coordination in solution, spectrophotometric pH titrations were carried out for all 20 metal complexes. The majority of the complexes undergo spectroscopic changes that are consistent with a switch in pendant coordination state at a specific pH. This ligand series represents a comprehensive model platform from which to build pH-switchable metal complexes for applications in nanoscience and biomedicine.

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“…In addition, Zn(II) complexes with macrocyclic polyamines as 1,4,7-triazacyclononane (tacn), 1,4,7,10-tetraazacyclododecane (cyclen) and 1,4,8,11-tetraazacyclotetradecane (cyclam) were tested for molecular recognition of nucleotides, amino acids and their peptides. Utilization of metal complexes with the azacycles was reviewed by Kőnig (Geduhn et al, 2007). On the basis of a number of examples from the literature, authors documented that complexes of transition metal ions with the azacycles are very stable, both thermodynamically and kinetically, in contrast to the reversible coordination of an incoming bioligand, and thus, the azacycle complexes could be a tool for the molecular recognition.…”

Section: Introductionmentioning

confidence: 99%

Dipeptide interactions with Zn(II)–cyclen artificial model for molecular recognition

Rostášová¹,

Vilková

Vargová³

et al. 2015

J of Molecular Recognition

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The Zn(II)-cyclen-dipeptide ternary systems (where cyclen is abbreviated as L and dipeptide is glycylglycine (HL(1)) or glycyl-(S)-alanine (HL(2))) were investigated by potentiometry applying both "out-of-cell" and direct titrations and by (1) H NMR spectroscopy. Especially, the (1)H NMR study was found to be very efficient to estimate speciation in the systems. The results obtained under full equilibria indicated two main species, [Zn(L)(HL(1,2))](2+) and [Zn(L)(L(1,2))](+), in both the systems. In the [Zn(L)(HL(1,2))](2+) complex, presence of carbonyl-carboxylate chelate was confirmed, and in the [Zn(L)(L(1,2))](+) species, the peptide coordination is re-organized to carbonyl-amine chelate or only terminal amino group is coordinated. Equilibrium constants describing [Zn(L)](2+)-dipeptide interaction are relatively low, log K = 3.4 for Gly-Gly and 4.1 for Gly-(S)-Ala, respectively. Nevertheless, the values are slightly higher than stability constants for interaction of Zn(II) with the dipeptides (i.e. [Zn(L(1,2))](+) species) where a chelate formation is expected. It indicates that interaction between Zn(II) ion in [Zn(L)](2+) and the dipeptides should be supported by some additional interactions. Potentiometry carried out under non-equilibrum condition showed different species where these additional stabilizing forces play more important role.

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Transition Metal Complexes of Some Azamacrocycles and Their Use in Molecular Recognition

Cited by 36 publications

References 69 publications

Cyclononanes: The extensive chemistry of fundamentally simple ligands

Cyclononanes: The extensive chemistry of fundamentally simple ligands

Molecular Switches for any pH: A Systematic Study of the Versatile Coordination Behaviour of Cyclam Scorpionands

Dipeptide interactions with Zn(II)–cyclen artificial model for molecular recognition

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