Synthetic and equilibrium studies on copper(<scp>II</scp>), nickel(<scp>II</scp>), and palladium(<scp>II</scp>) complexes of N,N′,N″,N‴-tetrakis(2-hydroxyethyl)-1,4,8,11-tetra-azacyclotetradecane (L); kinetics of the acid dissociation of the copper(<scp>II</scp>) complex and X-ray structural characterisation of the nickel(<scp>II</scp>) complex [NiLH<sub>–1</sub>][ClO<sub>4</sub>]

Hay, Robert W.; Pujari, Mahesh P.; Moodie, W. Thomas; Craig, Scott; Richens, David T.; Perotti, Angelo; Ungaretti, L.

doi:10.1039/dt9870002605

Cited by 52 publications

(19 citation statements)

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“…[Ni( L2 )] 2+ has not been structurally characterized, but this complex is most likely six‐coordinate with two pendents in 1,7‐positions bound to the Ni II , in analogy to the amide derivative of this macrocycle . [Ni( L3 )] 2+ is also most likely six‐coordinate based on a structure of a similar complex of CYCLAM with hydroxyethyl pendents . In this complex, the Ni II is in the plane of the 14‐membered ring and the two alcohol pendents in 1,8 positions occupy axial sites.…”

Section: Resultsmentioning

confidence: 99%

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Nickel(II) Complexes as Paramagnetic Shift and paraCEST Agents

et al. 2018

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Five Ni II macrocyclic complexes are studied as water proton shift agents and as paraCEST agents (paraCEST = paramagnetic chemical exchange saturation transfer) for MRI applications. The five macrocycles have amide and/or alcohol pendent groups with either tetraaza-or triazamacrocycles including 1,1′,1′′-(1,4,7-triazonane-1,4,7-triyl)tris(propan-2-ol) (L1), 1,1′,1′′,1′′′-(1,4,7,10-tetraazacyclododecane-1,4,7,10-tetra)tetrakis(propan-2-ol) (L2), 1,1′,1′′, 1′′′-(1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetrayl)tetrakis(propan-2-ol) (L3), 2,2′,2′′-(1,4,7triazonane-1,4,7-triyl)triacetamide (L4), or 2,2′-(7-benzyl-1,4,7triazonane-1,4-diyl) diacetamide (L5). Solution magnetic moments are consistent with paramagnetic Ni II complexes. The complexes are characterized by pH-potentiometric titrations to

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Section: Resultsmentioning

confidence: 99%

“…Ligand Synthesis: Macrocycles L1 , L2 , L3 and L4 were prepared as previously reported . 1‐Benzyl‐[1,4,7]triazacyclononane was synthesized according to a previously reported procedure .…”

Section: Methodsmentioning

confidence: 99%

Nickel(II) Complexes as Paramagnetic Shift and paraCEST Agents

et al. 2018

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“…For background to macrocycles with pendant coordinating groups, see: Madeyski et al (1984); Hay et al (1987); Melson (1979). For a related structure, see: Roy et al (2001).…”

Section: Related Literaturementioning

confidence: 99%

3,3′-(5,5,7,12,12,14-Hexamethyl-1,4,8,11-tetraazacyclotetradecane-1,8-diyl)dipropanonitrile methanol disolvate

Hao

Zhang

2010

Acta Cryst E

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The asymmetric unit of the title compound, C22H42N6·2CH4O, comprises one half of a 14-membered tetraazacyclotetradecane macrocycle with cyanoethyl substituents on one of the N atoms and a methanol solvent molecule. The macrocycle lies about an inversion centre. The cyanoethyl substituents are oriented so that the cyano groups lie over opposite faces of the central cavity of the macrocycle. The methanol solvate molecules lie away from the cavity of the macrocycle and are linked to the macrocycles via O—H⋯N hydrogen bonds.

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“…Macrocyclic complexes containing pendant donors are capable of forming intra-or intermolecular coordination. Pendant arms, usually bound to the nitrogen donor atoms, with substituents such as -CH 2 CH 2 NH 2 , -CH 2 COOH [4][5][6], and -CH 2 CH 2 OH [7] that can axially bind to the central nickel ion, shift the redox potential of the complex cathodically, i.e., stabilize the trivalent complex. Stabilization of such Ni(III)-hexaazamacrocyclic complexes has been studied in neutral and slightly alkaline aqueous solutions in the presence of stabilizing anionic ligands through the formation of Ni III LX 2 complexes (where X = F -, SO 4 2-, HPO 4 2-, HCO 2 -, C 6 H 5 CO 2 -, CH 3 CO 2 -and (CH 3 ) 3 CCO 2 -) [8].…”

Section: Introductionmentioning

confidence: 99%

Kinetics of oxidation of benzenediols by (1,8-bis(2-hydroxyethyl)-1,3,6,8,10,13-hexaazacyclotetradecane)nickel(III) in aqueous acidic media

Anuradha

Vijayaraghavan

2010

Reac Kinet Mech Cat

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The kinetics of the oxidation of hydroquinone (H 2 Q), catechol (H 2 cat) and substituted catechols with nickel(III) macrocycle [NiL 1 ] 3? (L 1 = 1,8-bis(2-hydroxyethyl)-1,3,6,8,10,13-hexaazacyclotetradecane) has been studied spectrophotometrically in aqueous perchloric acid in the presence of sulfate. Over the pH range 1-2.6, and at higher sulfate concentration 0.05 \ [SO 42-] \ 0.2 mol dm -3 , the decomposition of [Ni III L 1 ] in the oxidation of benzenediols via [Ni III-L 1 (OH)(H 2 O)] is small. With hydroquinone, the rate constant is almost independent of the hydrogen ion concentration and with catechols, the involvement of catechol anion (Hcat -) has been considered. The rate constants for cross reactions are discussed in terms of the Marcus relationship.

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Cited by 52 publications

References 1 publication

Nickel(II) Complexes as Paramagnetic Shift and paraCEST Agents

Nickel(II) Complexes as Paramagnetic Shift and paraCEST Agents

3,3′-(5,5,7,12,12,14-Hexamethyl-1,4,8,11-tetraazacyclotetradecane-1,8-diyl)dipropanonitrile methanol disolvate

Kinetics of oxidation of benzenediols by (1,8-bis(2-hydroxyethyl)-1,3,6,8,10,13-hexaazacyclotetradecane)nickel(III) in aqueous acidic media

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