Structure of a gadolinium hexaaza macrocycle complex with a Gd2(OAc)8 counterion

Smith, Paul H.; Ryan, R. R.

doi:10.1107/s0108270192003810

Cited by 6 publications

(12 citation statements)

References 4 publications

(5 reference statements)

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“…16,17 Ln(III) complexations with hexahomotrioxacalix[3]arene macrocylic ligands have been known to form dimers containing bridging aryloxide oxygen atoms as well. 18 Other examples of polynuclear Ln(III) complexes are those with bridging acetates 19,20 and with bridging trifluoroacetates. 17 In the development of MRI agents, some multinuclear Ln(III) complexes have been found.…”

Section: Introductionmentioning

confidence: 99%

Homotrinuclear Lanthanide(III) Arrays: Assembly of and Conversion from Mononuclear and Dinuclear Units

et al. 2000

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The reactions of potentially hexadentate H2bbpen (N,N'-bis(2-hydroxybenzyl)-N,N'-bis(2-pyridylmethyl)-ethylenediamine, H2L1), H2(Cl)bbpen (N,N'-bis(5-chloro-2-hydroxybenzyl)-N,N'-bis(2-pyridylmethyl)ethylenediamine, H2L2), and H2(Br)bbpen (N,N'-bis(5-bromo-2-hydroxybenzyl)-N,N'-bis(2-pyridylmethyl)ethylenediamine, H2L3) with Ln(III) ions in the presence of a base in methanol resulted in three types of complexes: neutral mononuclear ([LnL(NO3)]), monocationic dinuclear ([Ln2L2(NO3)]+), and monocationic trinuclear ([Ln3L2(X)n(CH3OH)]+), where X = bridging (CH3COO-) and bidentate ligands (NO3-, CH3COO-, ClO4-) and n is 4. The formation of a complex depends on the base (hydroxide or acetate) and the size of the respective Ln(III) ion. All complexes were characterized by infrared spectroscopy, mass spectrometry, and elemental analyses; in some cases, X-ray diffraction studies were also performed. The structures of the neutral mononuclear [Yb(L1)(NO3)], dinuclear [Pr2(L1)2(NO3)(H2O)]NO3.CH3OH and [Gd2(L1)2(NO3)]NO3.CH3OH.3H2O, and trinuclear [Gd3(L3)2(CH3COO)4(CH3OH)]ClO4.5CH3OH and [Sm3(L1)2(CH3COO)2(NO3)2(CH3OH)]NO3.CH3OH.3.65H2O were solved by X-ray crystallography. The [LnL(NO3)] or [Ln2L2(NO3)]+ complexes could be converted to [Ln3L2(X)n(CH3OH)]+ complexes by the addition of 1 equiv of a Ln(III) salt and 2-3 equiv of sodium acetate in methanol. The trinuclear complexes were found to be the most stable of the three types, which was evident from the presence of the intact monocationic high molecular weight parent peaks ([Ln3L2(X)n]+) in the mass spectra of all the trinuclear complexes and from the ease of conversion from the mononuclear or dinuclear to the trinuclear species. The incompatibility of the ligand denticity with the coordination requirements of the Ln(III) ions was proven to be a useful tool in the construction of multinuclear Ln(III) metal ion arrays.

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Section: Introductionmentioning

confidence: 99%

Homotrinuclear Lanthanide(III) Arrays: Assembly of and Conversion from Mononuclear and Dinuclear Units

et al. 2000

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“…Dimeric [Ln 2 (OAc) 8 ] 2À units are known in the literature and even found in some applications in cryogenics, [10] but are extremely rare. The only previously published compound that contains this unit with identical coordination modes is a Gd hexaaza macrocycle complex (2[Gd(C 22 [11] Hydrates such as [Ln 2 (OAc) 8 (H 2 O) 2 ] 2À have been observed with a few lanthanides (LaÀ Sm), [12] but with different acetate coordination modes (three η 2 μk 2 and one η 3 μ 2 k 2 per Ln atom [10,14] have been observed for the heavier Ln (EuÀ Lu) exhibiting the same η 2 μk 2 and η 3 μ 2 k 2 modes as the latter. Though the η 2 μ 2 k 2 coordination mode could still be obtained in the fluorinated Tb 2 (CF 3 COO) 6 (H 2 O) 6 , all initial η 3 μ 2 k 2 bridges have been distorted resulting in η 2 μ 2 k 2 .…”

Section: Structural Resultsmentioning

confidence: 99%

“…Dimeric [Ln 2 (OAc) 8 ] 2− units are known in the literature and even found in some applications in cryogenics, [10] but are extremely rare. The only previously published compound that contains this unit with identical coordination modes is a Gd hexaaza macrocycle complex (2[Gd(C 22 H 26 N 6 )‐(C 2 H 3 O 2 ) 2 ][Gd 2 (C 2 H 3 O 2 ) 8 ] ⋅ C 6 H 6 ⋅ 4CHCl 3 ) where [Gd 2 (OAc) 8 ] 2− plays the role of a counterion [11] . Hydrates such as [Ln 2 (OAc) 8 (H 2 O) 2 ] 2− have been observed with a few lanthanides (La−Sm), [12] but with different acetate coordination modes (three η 2 μκ 2 and one η 3 μ 2 κ 2 per Ln atom).…”

Section: Resultsmentioning

confidence: 99%

“…The only previously published compound that contains this unit with identical coordination modes is a Gd hexaaza macrocycle complex (2[Gd(C 22 H 26 N 6 )‐(C 2 H 3 O 2 ) 2 ][Gd 2 (C 2 H 3 O 2 ) 8 ] ⋅ C 6 H 6 ⋅ 4CHCl 3 ) where [Gd 2 (OAc) 8 ] 2− plays the role of a counterion. [11] Hydrates such as [Ln 2 (OAc) 8 (H 2 O) 2 ] 2− have been observed with a few lanthanides (La−Sm), [12] but with different acetate coordination modes (three η 2 μκ 2 and one η 3 μ 2 κ 2 per Ln atom). Other pure, dimeric Ln tetra‐carboxylato complexes include [Eu 2 (CH 3 BzO) 8 ] 2− and [Ho 2 (butenoate) 8 ] 2− with rather large aromatic counterions.…”

Section: Resultsmentioning

confidence: 99%

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Ready Access to Anhydrous Anionic Lanthanide Acetates by Using Imidazolium Acetate Ionic Liquids as the Reaction Medium

Bousrez

Renier

Kelley

et al. 2021

Chemistry A European J

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Access to lanthanide acetate coordination compounds is challenged by the tendency of lanthanides to coordinate water and the plethora of acetate coordination modes. A straightforward, reproducible synthetic procedure by treating lanthanide chloride hydrates with defined ratios of the ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate ([C 2 mim][OAc]) has been developed. This reaction pathway leads to two isostructural crystalline anhydrous coordination complexes, the polymeric [C 2 mim] n [{Ln 2 (OAc) 7 } n ] and the dimeric [C 2 mim] 2 [Ln 2 (OAc) 8 ], based on the ion size and the ratio of IL used. A reaction with an IL : Ln-salt ratio of 5 : 1, where Ln = Nd, Sm, and Gd, led exclusively to the polymer, whilst for the heaviest lanthanides (DyÀ Lu) the dimer was observed. Reaction with Eu and Tb resulted in a mixture of both polymeric and dimeric forms. When the amount of IL and/or the size of the cation was increased, the reaction led to only the dimeric compound for all the lanthanide series. Crystallographic analyses of the resulting salts revealed three different types of metal-acetate coordination modes where η 2 μk 2 is the most represented in both structure types.

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“…In addition to hydrogen bonding between the 2,6-diamidopyridine part of ( 160) and thymine, the pyruvate is held in close proximity by binding to the N a + cation bound in the benzo-15-crown-5 ring. '39 The ligands ( 161) and ( 162) form complexes with N a + and K + offormula [Na(l61)]+, [K( 161),]+, [Naz (162)]2+, and [K (162)]+. In the presence of equimolar amounts of N a + and K + (162) demonstrated remarkable selectivity for K + .…”

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confidence: 99%

Chapter 19. The coordination chemistry of macrocyclic ligands

McWhinnie¹

1993

Annu. Rep. Prog. Chem., Sect. A

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Structure of a gadolinium hexaaza macrocycle complex with a Gd2(OAc)8 counterion

Abstract: Abstract. Di[bis(acetato-O,

Cited by 6 publications

References 4 publications

Homotrinuclear Lanthanide(III) Arrays: Assembly of and Conversion from Mononuclear and Dinuclear Units

Homotrinuclear Lanthanide(III) Arrays: Assembly of and Conversion from Mononuclear and Dinuclear Units

Ready Access to Anhydrous Anionic Lanthanide Acetates by Using Imidazolium Acetate Ionic Liquids as the Reaction Medium

Chapter 19. The coordination chemistry of macrocyclic ligands

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