Effect of Polyether Ligands on Stabilities and Mass Transport Properties of a Series of Gadolinium(III) .beta.-Diketonate Complexes

Baxter, Ian; Drake, Simon R.; Hursthouse, Michael B.; Malik, K. M. Abdul; McAleese, John; Otway, David J.; Plakatouras, John C.

doi:10.1021/ic00110a016

Cited by 88 publications

(52 citation statements)

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“…The Yb–O bond distances span the range 2.424–2.543 Å and they are in good agreement with previously reported values [7, 8, 17–21, 28], taking into account the lanthanide contraction. Though neutral, the etheric oxygen atoms appear to be coordinated to Yb III stronger than the nitrates (mean Yb–O nitrato = 2.47, Yb–O ether = 2.43 Å).…”

Section: Resultssupporting

confidence: 92%

Interactions of Trivalent Lanthanide Cations with a New Hexadentate Di‐Schiff Base: New Lanthanide(III) Complexes from (NE,N^′E)‐2,2^′‐(ethane‐1,2‐diylbis(oxy))bis(N‐(pyridin‐2‐ylmethylene)ethanamine)

Tsiouri

Skorda

Papadimitriou

et al. 2010

Bioinorganic Chemistry and Applications

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The novel lanthanide(III) complexes [Ln(NO3)2L](NO3)·3MeOH (Ln = La 1, Pr 2) and [Ln(NO3)3L](NO3)·2MeOH (Ln = Gd 3, Yb 4), where L = (NE,N′E)-2,2′-(ethane-1,2-diylbis(oxy))bis(N-(pyridin-2-ylmethylene)ethanamine), have been obtained by direct reaction of the Schiff base ligand and the corresponding hydrated lanthanide(III) nitrates in methanol. All complexes were characterized spectroscopically and thermogravimetrically. Complex 4 was also characterized with crystallographic studies: orthorhombic P212121, a = 10.6683(14), b = 13.4752(15), c = 19.3320(26) Å. In the molecular structure of 4, Yb(III) is surrounded by all donor atoms of the Schiff base (four nitrogen and two oxygen atoms) and four oxygen atoms belonging to two bidentate chelating nitrato ligands.

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Section: Resultssupporting

confidence: 92%

Interactions of Trivalent Lanthanide Cations with a New Hexadentate Di‐Schiff Base: New Lanthanide(III) Complexes from (NE,N^′E)‐2,2^′‐(ethane‐1,2‐diylbis(oxy))bis(N‐(pyridin‐2‐ylmethylene)ethanamine)

Tsiouri

Skorda

Papadimitriou

et al. 2010

Bioinorganic Chemistry and Applications

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“…where m, δi and θi are the number of possible edges (m = 15 in this study [28] ), the observed dihedral angle between planes along the ith edge and the dihedral angle for the ideal structure, respectively. The estimated S values of lanthanide complexes were summarized in Tables S2 and S3.…”

Section: Resultsmentioning

confidence: 99%

Seven‐Coordinate Luminophores: Brilliant Luminescence of Lanthanide Complexes with C_3v Geometrical Structures

et al. 2015

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Enhanced Luminescence properties of mononuclear lanthanide complexes with asymmetric seven-coordination structure are reported for the first time. The lanthanide complexes are composed of a lanthanide ion (Eu III or Tb III ), three tetramethyl heptanedionatos and one triphenyl phosphine oxide. The coordination geometries of the lanthanide complexes are evaluated using single crystal X-ray analyses and shape-measurement calculations. The complexes are categorized to be seven-coordinate monocapped octahedral structure (point group: C3v). The sevencoordinate lanthanide complexes show high intrinsic emission quantum yields, extra-large radiative rate constants and unexpected small non-radiative rate constants. The brilliant luminescence properties are elucidated in terms of the asymmetric coordination geometry and small vibrational quanta related to the thermal relaxation.

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“…Heptaglyme (heptaethyleneglycol dimethyl ether) has been used as a multidentate ligand in Ba (FIXKAY; Wei et al, 1987), Ca (RUFWUK; Arunasalam et al, 1997) and Gd (YOMBUX; Baxter et al, 1995) complexes. The heptaglyme conformations in these crystals differ substantially from the chain geometry found in (I).…”

Section: Tablementioning

confidence: 99%

“…Table 2 Hydrogen-bond geometry (Å , ). Baxter et al, 1995) complexes. The heptaglyme conformations in these crystals differ substantially from the chain geometry found in (I).…”

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Naloxegol hydrogen oxalate displaying a hydrogen-bonded layer structure

et al. 2018

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In the salt (5 ,6 )-6- [(2,5,8,11,14,17,20-heptaoxadocosan-22-yl)oxy]-3,14-dihydroxy-17-(prop-2-en-1-yl)-4,5-epoxymorphinan-17-ium hydrogen oxalate, C 34 H 54 NO 11 + ÁC 2 HO 4 À the polyether unit of the naloxegol cation adopts the shape of a squashed open letter 'O'. In the crystal, the hydrogen oxalate anions are linked into a chain by O-HÁ Á ÁO hydrogen bonds. Each naloxegol unit is hydrogen bonded to three hydrogen oxalate ions via two O-HÁ Á ÁO and one N-HÁ Á ÁO interactions. The resulting hydrogen-bonded two-dimensional layer structure is 3,5-connected and has the 3,5 L50 topology. Chemical contextNaloxegol {(5 ,6 )-17-allyl-6- [(20-hydroxy-3,6,9,12,15,18-hexaoxaicos-1-yl)oxy]-4,5-epoxymorphinan-3,14-diol} is a pegylated derivative of naloxone which serves as a peripherally acting m-opioid receptor antagonist. This compound was developed for the oral treatment of opioid-induced constipation in adults with chronic non-cancer pain, and is currently marketed under the trade name Movantik by AstraZeneca. Å slund et al. (2012) have described two forms, denoted as A and B, of naloxegol oxalate. Form B was reported as showing 'a sharp endothermic peak at 92.5 C' (365.5 K) in the DSC thermogram with a heat of fusion of Á fus H = 96.1 J g À1 (71.29 kJ mol À1 ). Herein we report the crystal structure of naloxegol hydrogen oxalate (I) (C 34 H 54 NO 11 + C 2 HO 4 À ), which is identical with form B described by Å slund et al. (2012). The unequivocal identity with form B is evidenced by the match of the X-ray powder diffraction data and the good agreement of the melting data [T fus(onset) = 363.9 AE 0.3 K, T fus(peak) = 366.7 AE 0.3 K, Á fus H = 70.4 AE 0.6 kJ mol À1 ] with those reported by Å slund et al. Structural commentaryThe geometry of the morphine scaffold in the title structure (I) is very similar to that of the parent molecule in the naloxone hydrochloride dihydrate structure (Klein et al., 1987), except for the conformation of the cyclohexyl ring (C2-C6/C11) (Figs. ISSN 2056-9890 1 and 2). In (I), the puckering parameters for this ring of q = 85.3 (2) and = 76.6 (3) indicate a conformation between boat and twist boat (Cremer & Pople, 1975;Boeyens, 1978). The conformation of the 2-propenyl group at N8 is characterised by the torsion angle N8-C43-C44-C45 of 133.6 (4) , which differs substantially from the corresponding value, À96.2 , in the naloxone hydrochloride dihydrate. The polyether unit adopts the shape of a squashed open letter O. Using the nomenclature for torsion angles recommended by Markley et al. (1998), the conformation of the fragment (C3, O19-C41) can be described by the sequenceAll O-C-C-O angles are gauche except for O25-C26-C27-O28. Six consecutive gauchetype torsion angles are associated with a 180 turn within the chain section (C26-O34) ( Fig. 1, Table 1). The hydrogen oxalate anion displays a twisted conformation with a torsion angle O1O-C2O-C4O-O5O of À143.3 (3) . Supramolecular featuresThe naloxegol cation contains one NH group and two OH groups, which can serve as hydrogen-bond don...

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Effect of Polyether Ligands on Stabilities and Mass Transport Properties of a Series of Gadolinium(III) .beta.-Diketonate Complexes

Cited by 88 publications

References 1 publication

Interactions of Trivalent Lanthanide Cations with a New Hexadentate Di‐Schiff Base: New Lanthanide(III) Complexes from (NE,N^′E)‐2,2^′‐(ethane‐1,2‐diylbis(oxy))bis(N‐(pyridin‐2‐ylmethylene)ethanamine)

Interactions of Trivalent Lanthanide Cations with a New Hexadentate Di‐Schiff Base: New Lanthanide(III) Complexes from (NE,N^′E)‐2,2^′‐(ethane‐1,2‐diylbis(oxy))bis(N‐(pyridin‐2‐ylmethylene)ethanamine)

Seven‐Coordinate Luminophores: Brilliant Luminescence of Lanthanide Complexes with C_3v Geometrical Structures

Naloxegol hydrogen oxalate displaying a hydrogen-bonded layer structure

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Effect of Polyether Ligands on Stabilities and Mass Transport Properties of a Series of Gadolinium(III) .beta.-Diketonate Complexes

Cited by 88 publications

References 1 publication

Interactions of Trivalent Lanthanide Cations with a New Hexadentate Di‐Schiff Base: New Lanthanide(III) Complexes from (NE,N′E)‐2,2′‐(ethane‐1,2‐diylbis(oxy))bis(N‐(pyridin‐2‐ylmethylene)ethanamine)

Interactions of Trivalent Lanthanide Cations with a New Hexadentate Di‐Schiff Base: New Lanthanide(III) Complexes from (NE,N′E)‐2,2′‐(ethane‐1,2‐diylbis(oxy))bis(N‐(pyridin‐2‐ylmethylene)ethanamine)

Seven‐Coordinate Luminophores: Brilliant Luminescence of Lanthanide Complexes with C3v Geometrical Structures

Naloxegol hydrogen oxalate displaying a hydrogen-bonded layer structure

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Interactions of Trivalent Lanthanide Cations with a New Hexadentate Di‐Schiff Base: New Lanthanide(III) Complexes from (NE,N^′E)‐2,2^′‐(ethane‐1,2‐diylbis(oxy))bis(N‐(pyridin‐2‐ylmethylene)ethanamine)

Interactions of Trivalent Lanthanide Cations with a New Hexadentate Di‐Schiff Base: New Lanthanide(III) Complexes from (NE,N^′E)‐2,2^′‐(ethane‐1,2‐diylbis(oxy))bis(N‐(pyridin‐2‐ylmethylene)ethanamine)

Seven‐Coordinate Luminophores: Brilliant Luminescence of Lanthanide Complexes with C_3v Geometrical Structures