Iron and Cobalt "Lacunar" Complexes as Dioxygen Carriers

Busch, Daryle H.; Alcock, Nathaniel W.

doi:10.1021/cr00027a003

Cited by 193 publications

(175 citation statements)

References 53 publications

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“…Ϫ IR (KBr): (19). Ϫ a) Procedure A: Cyclam (7.00 g, 35 mmol) was dissolved in 3.5 l of chloro-1, 10,13,dicosane (22): The procedure form in the presence of 9.3 g of anhydrous sodium carbonate. A described for 17 was carried out using 2.0 g of cyclam (10 mmol), solution of α,αЈ-dibromo-m-xylene (12.7 g, 48.1 mmol) in 500 ml 3.5 g of 1,8-dibromooctane (13 mmol), and 2.7 g of anhydrous of chloroform was added dropwise over a period of 12 h and then sodium carbonate in refluxing acetonitrile.…”

Section: Methodsmentioning

confidence: 99%

Synthesis of Macropolycyclic Ligands Based on Tetraazacycloalkanes

Brandès¹,

Denat²,

Lacour³

et al. 1998

Eur. J. Org. Chem.

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A versatile synthesis of spherical macrobicyclic and cylindrical macrotricyclic ligands is described using 1,4,8,11‐tetraazacyclotetradecane (cyclam), 1,4,7,10‐tetraazacyclododecane (cyclen), or dioxo macrocycles as precursors. Macrobicycles have been obtained by allowing cyclam, cyclen, or 5,12‐dioxocyclam (1,4,8,11‐tetraazacyclotetradecane‐5,12‐dione) to react with a bis‐electrophilic spacer under high dilution conditions. A surprising selectivity has been observed for 2,6‐dioxocyclen (1,4,7,10‐tetraazacyclododecane‐2,6‐dione), which yields only macrotricycles under the same reaction conditions. Molecular modelling studies have been carried out to investigate the selectivity of the reactions, and good agreement has been observed between the theoretical predictions and experimental data. 1D‐ and 2D‐NMR studies reveal a highly rigid structure in the case of macrobicycles. The macropolycyclic ligands show very different basicities, which demonstrates the influence of the cross‐linker on the coordination properties of the ligands.

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Section: Methodsmentioning

confidence: 99%

Synthesis of Macropolycyclic Ligands Based on Tetraazacycloalkanes

Brandès¹,

Denat²,

Lacour³

et al. 1998

Eur. J. Org. Chem.

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“…Busch [8] has observed in his extensive studies of "lacunar" cyclidene complexes that substitution at the bridge nitrogen atoms strongly affects the oxidation potential of coordinated metal ions. Here we describe the role of N-methylation in controlling the properties of bismacrocyclic substrates used for the construction of more complex molecules.…”

Section: Introductionmentioning

confidence: 99%

Fine‐Tuning of Properties of Bismacrocyclic Dinuclear Cyclidene Receptors by N‐Methylation

Domagała

Więckowska

Kowalski

et al. 2006

Chemistry A European J

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N-Methylated bismacrocyclic Cu and Ni complexes were synthesised and structurally characterised in the solid state. Their properties in solution were analysed by using NMR and ESR spectroscopies and electrochemical methods. Face-to-face biscyclidenes linked through polymethylene chains form rectangular boxlike cations. These moieties can host some small guest molecules (water, pi-electron donating compounds) and are stabilised by a shell of neighbouring counterions. For the bismacrocyclic dinuclear complexes containing two nickel or two copper ions, the intramolecular interactions between the metallic centres are strengthened through methylation of the macrocyclic components, as compared with the nonmethylated species. We report the electron coupling created by two unpaired electrons coming from two copper centres observed by ESR spectroscopy. Methylation weakens the electron-acceptor properties of the complexes, which leads to less effective binding of the pi-electron-donating guests. It also increases the stability of the lower oxidation states. In the case of the copper complexes, both Cu(II)/Cu(I) and Cu(II)/Cu(III) reversible one-electron transfers are seen in the voltammograms. These changes in properties are interpreted as the consequences of steric repulsion between the methyl substituents and the macrocyclic ring.

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“…Cyclidenes [12,13] -being a representative example of metal complexes -combine the ease of synthesis and modification with rich electrochemistry and spectroscopic properties. They are waterstable π-electron rich tetraazamacrocyclic systems (also called Jäger complexes), that during the last decade they have been used by the group of Korybut-Daszkiewicz as building blocks for the synthesis of a range of macrocycles, including linear compounds, oligomacrocycles, [14,15] catenanes, [16,17] pseudorotaxanes [18] and rotaxanes.…”

Section: Introductionmentioning

confidence: 99%

“…[20] The 14-membered cyclidene units are relatively easy to obtain [21][22][23] and able to coordinate various transition metal ions, such as copper(II), nickel(II), but also iron(II), cobalt(II, III), palladium(II) and platinum(II, IV). [13,23] The rings are π-electron rich and almost ideally planar. As a consequence, the π-π-stacking can be observed in most of X-ray structures of cyclidene derivatives [14,[23][24][25][26] The solubility of the complexes is determined by functional groups attached to the macrocycle and also depends on the type of counterion used for the crystallisation.…”

Section: Introductionmentioning

confidence: 99%

Tetraaza[14]macrocyclic Transition Metal Complexes as DNA Intercalators

2015

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Six tetraazamacrocyclic copper(II) and nickel(II) complexes have been synthesised and their interactions with double‐stranded DNA (calf thymus DNA) have been studied using circular and linear dichroism, as well as other spectroscopic methods. The ability of these complexes to intercalate between DNA base pairs has been demonstrated qualitatively and confirmed by determining the stoichiometry and association constant values; these were found to range from 8.5 × 103 – 2.8 × 104 L mol–1. The nickel(II) complexes, being more electron‐deficient, seem to have higher binding abilities than guests containing the copper ion. It has also been shown that not only CD, but also linear dichroism, can be a very useful tool for carrying out qualitative DNA interaction studies.

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Iron and Cobalt "Lacunar" Complexes as Dioxygen Carriers

Cited by 193 publications

References 53 publications

Synthesis of Macropolycyclic Ligands Based on Tetraazacycloalkanes

Synthesis of Macropolycyclic Ligands Based on Tetraazacycloalkanes

Fine‐Tuning of Properties of Bismacrocyclic Dinuclear Cyclidene Receptors by N‐Methylation

Tetraaza[14]macrocyclic Transition Metal Complexes as DNA Intercalators

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