---
_id: '62854'
abstract:
- lang: eng
text: Highly selective rare-earth separation has become increasingly important due
to the indispensable role of these elements in various cutting-edge technologies
including clean energy. However, the similar physicochemical properties of rare-earth
elements (REEs) render their separation very challenging, and the development
of new selective receptors for these elements is potentially of very considerable
economic and environmental importance. Herein, we report the development of a
series of 4-phosphoryl pyrazolone receptors for the selective separation of trivalent
lanthanum, europium, and ytterbium as the representatives of light, middle, and
heavy REEs, respectively. X-ray crystallography studies were employed to obtain
solid-state structures across 11 of the resulting complexes, allowing comparative
structure–function relationships to be probed, including the effect of lanthanide
contraction that occurs along the series from lanthanum to europium to ytterbium
and which potentially provides a basis for REE ion separation. In addition, the
influence of ligand structure and lipophilicity on lanthanide binding and selectivity
was systematically investigated via n-octanol/water distribution and liquid–liquid
extraction (LLE) studies. Corresponding stoichiometry relationships between solid
and solution states were well established using slope analyses. The results provide
new insights into some fundamental lanthanide coordination chemistry from a separation
perspective and establish 4-phosphoryl pyrazolone derivatives as potential practical
extraction reagents for the selective separation of REEs in the future.
author:
- first_name: Jianfeng
full_name: Zhang, Jianfeng
last_name: Zhang
- first_name: Marco
full_name: Wenzel, Marco
last_name: Wenzel
- first_name: Kathleen
full_name: Schnaars, Kathleen
id: '117735'
last_name: Schnaars
- first_name: Felix
full_name: Hennersdorf, Felix
last_name: Hennersdorf
- first_name: Leonard F.
full_name: Lindoy, Leonard F.
last_name: Lindoy
- first_name: Jan J.
full_name: Weigand, Jan J.
last_name: Weigand
citation:
ama: Zhang J, Wenzel M, Schnaars K, Hennersdorf F, Lindoy LF, Weigand JJ. Highly
Tunable 4-Phosphoryl Pyrazolone Receptors for Selective Rare-Earth Separation.
Inorganic Chemistry. 2023;62(7):3212-3228. doi:10.1021/acs.inorgchem.2c04221
apa: Zhang, J., Wenzel, M., Schnaars, K., Hennersdorf, F., Lindoy, L. F., &
Weigand, J. J. (2023). Highly Tunable 4-Phosphoryl Pyrazolone Receptors for Selective
Rare-Earth Separation. Inorganic Chemistry, 62(7), 3212–3228. https://doi.org/10.1021/acs.inorgchem.2c04221
bibtex: '@article{Zhang_Wenzel_Schnaars_Hennersdorf_Lindoy_Weigand_2023, title={Highly
Tunable 4-Phosphoryl Pyrazolone Receptors for Selective Rare-Earth Separation},
volume={62}, DOI={10.1021/acs.inorgchem.2c04221},
number={7}, journal={Inorganic Chemistry}, publisher={American Chemical Society
(ACS)}, author={Zhang, Jianfeng and Wenzel, Marco and Schnaars, Kathleen and Hennersdorf,
Felix and Lindoy, Leonard F. and Weigand, Jan J.}, year={2023}, pages={3212–3228}
}'
chicago: 'Zhang, Jianfeng, Marco Wenzel, Kathleen Schnaars, Felix Hennersdorf, Leonard
F. Lindoy, and Jan J. Weigand. “Highly Tunable 4-Phosphoryl Pyrazolone Receptors
for Selective Rare-Earth Separation.” Inorganic Chemistry 62, no. 7 (2023):
3212–28. https://doi.org/10.1021/acs.inorgchem.2c04221.'
ieee: 'J. Zhang, M. Wenzel, K. Schnaars, F. Hennersdorf, L. F. Lindoy, and J. J.
Weigand, “Highly Tunable 4-Phosphoryl Pyrazolone Receptors for Selective Rare-Earth
Separation,” Inorganic Chemistry, vol. 62, no. 7, pp. 3212–3228, 2023,
doi: 10.1021/acs.inorgchem.2c04221.'
mla: Zhang, Jianfeng, et al. “Highly Tunable 4-Phosphoryl Pyrazolone Receptors for
Selective Rare-Earth Separation.” Inorganic Chemistry, vol. 62, no. 7,
American Chemical Society (ACS), 2023, pp. 3212–28, doi:10.1021/acs.inorgchem.2c04221.
short: J. Zhang, M. Wenzel, K. Schnaars, F. Hennersdorf, L.F. Lindoy, J.J. Weigand,
Inorganic Chemistry 62 (2023) 3212–3228.
date_created: 2025-12-04T12:10:57Z
date_updated: 2025-12-04T12:19:26Z
department:
- _id: '985'
doi: 10.1021/acs.inorgchem.2c04221
extern: '1'
intvolume: ' 62'
issue: '7'
language:
- iso: eng
page: 3212-3228
publication: Inorganic Chemistry
publication_identifier:
issn:
- 0020-1669
- 1520-510X
publication_status: published
publisher: American Chemical Society (ACS)
quality_controlled: '1'
status: public
title: Highly Tunable 4-Phosphoryl Pyrazolone Receptors for Selective Rare-Earth Separation
type: journal_article
user_id: '117735'
volume: 62
year: '2023'
...
---
_id: '62851'
abstract:
- lang: eng
text: To reduce high-level radiotoxic waste generated by nuclear power plants, highly
selective separation agents for minor actinides are mandatory. The mixed N,O-donor
ligand N,N,N′,N′-tetrakis[(6-carboxypyridin-2-yl)methyl]ethylenediamine (H4TPAEN;
1) has shown good performance as a masking agent in Am3+/Eu3+ separation studies.
Adjustments on the pyridyl backbone to raise the hydrophilicity led to a decrease
in selectivity and a decrease in M3+–Nam interactions. An enhanced basicity of
the pyridyl N-donors was given as a cause. In this work, we examine whether a
decrease in O-donor basicity can promote the M3+–Nam interactions. Therefore,
we replace the deprotonated “charged” carboxylic acid groups of TPAEN4– by neutral
amide groups and introduce N,N,N′,N’-tetrakis[(6-N″,N′′-diethylcarbamoylpyridin-2-yl)methyl]ethylenediamine
(TPAMEN; 2) as a new ligand. TPAMEN was crystallized with Eu(OTf)3 and Eu(NO3)3·6H2O
to form positively charged 1:1 [Eu(TPAMEN)]3+ complexes in the solid state. Alterations
in the M–O/N bond distances are compared to [Eu(TPAEN)]− and investigated by DFT
calculations to expose the differences in charge/energy density distributions
at europium(III) and the donor functionalities of the TPAEN4– and TPAMEN. On the
basis of estimations of the bond orders, atomic charges spin populations, and
density of states in the Eu and potential Am and Cm complexes, the specific contributions
of the donor–metal interaction are analyzed. The prediction of complex formation
energy differences for the [M(TPAEN)]− and [M(TPAMEN)]3+ (M3+ = Eu3+, Am3+) complexes
provide an outlook on the potential performance of TPAMEN in Am3+/Eu3+ separation.
author:
- first_name: Kathleen
full_name: Schnaars, Kathleen
id: '117735'
last_name: Schnaars
- first_name: Masashi
full_name: Kaneko, Masashi
last_name: Kaneko
- first_name: Kiyoshi
full_name: Fujisawa, Kiyoshi
last_name: Fujisawa
citation:
ama: Schnaars K, Kaneko M, Fujisawa K. Effect of Oxygen-Donor Charge on Adjacent
Nitrogen-Donor Interactions in Eu3+ Complexes of Mixed N,O-Donor Ligands
Demonstrated on a 10-Fold [Eu(TPAMEN)]3+ Chelate Complex. Inorganic
Chemistry. 2021;60(4):2477-2491. doi:10.1021/acs.inorgchem.0c03405
apa: Schnaars, K., Kaneko, M., & Fujisawa, K. (2021). Effect of Oxygen-Donor
Charge on Adjacent Nitrogen-Donor Interactions in Eu3+ Complexes of
Mixed N,O-Donor Ligands Demonstrated on a 10-Fold [Eu(TPAMEN)]3+ Chelate
Complex. Inorganic Chemistry, 60(4), 2477–2491. https://doi.org/10.1021/acs.inorgchem.0c03405
bibtex: '@article{Schnaars_Kaneko_Fujisawa_2021, title={Effect of Oxygen-Donor Charge
on Adjacent Nitrogen-Donor Interactions in Eu3+ Complexes of Mixed
N,O-Donor Ligands Demonstrated on a 10-Fold [Eu(TPAMEN)]3+ Chelate
Complex}, volume={60}, DOI={10.1021/acs.inorgchem.0c03405},
number={4}, journal={Inorganic Chemistry}, publisher={American Chemical Society
(ACS)}, author={Schnaars, Kathleen and Kaneko, Masashi and Fujisawa, Kiyoshi},
year={2021}, pages={2477–2491} }'
chicago: 'Schnaars, Kathleen, Masashi Kaneko, and Kiyoshi Fujisawa. “Effect of Oxygen-Donor
Charge on Adjacent Nitrogen-Donor Interactions in Eu3+ Complexes of
Mixed N,O-Donor Ligands Demonstrated on a 10-Fold [Eu(TPAMEN)]3+ Chelate
Complex.” Inorganic Chemistry 60, no. 4 (2021): 2477–91. https://doi.org/10.1021/acs.inorgchem.0c03405.'
ieee: 'K. Schnaars, M. Kaneko, and K. Fujisawa, “Effect of Oxygen-Donor Charge on
Adjacent Nitrogen-Donor Interactions in Eu3+ Complexes of Mixed N,O-Donor
Ligands Demonstrated on a 10-Fold [Eu(TPAMEN)]3+ Chelate Complex,”
Inorganic Chemistry, vol. 60, no. 4, pp. 2477–2491, 2021, doi: 10.1021/acs.inorgchem.0c03405.'
mla: Schnaars, Kathleen, et al. “Effect of Oxygen-Donor Charge on Adjacent Nitrogen-Donor
Interactions in Eu3+ Complexes of Mixed N,O-Donor Ligands Demonstrated
on a 10-Fold [Eu(TPAMEN)]3+ Chelate Complex.” Inorganic Chemistry,
vol. 60, no. 4, American Chemical Society (ACS), 2021, pp. 2477–91, doi:10.1021/acs.inorgchem.0c03405.
short: K. Schnaars, M. Kaneko, K. Fujisawa, Inorganic Chemistry 60 (2021) 2477–2491.
date_created: 2025-12-04T12:06:36Z
date_updated: 2025-12-04T12:19:31Z
department:
- _id: '985'
doi: 10.1021/acs.inorgchem.0c03405
extern: '1'
intvolume: ' 60'
issue: '4'
language:
- iso: eng
page: 2477-2491
publication: Inorganic Chemistry
publication_identifier:
issn:
- 0020-1669
- 1520-510X
publication_status: published
publisher: American Chemical Society (ACS)
quality_controlled: '1'
status: public
title: Effect of Oxygen-Donor Charge on Adjacent Nitrogen-Donor Interactions in Eu3+
Complexes of Mixed N,O-Donor Ligands Demonstrated on a 10-Fold [Eu(TPAMEN)]3+
Chelate Complex
type: journal_article
user_id: '117735'
volume: 60
year: '2021'
...
---
_id: '62855'
abstract:
- lang: eng
text: Two N,N'-bis(3-alkoxy-2-hydroxybenzyl)cyclohexane-1,2-diamine proligands,
H2L1 (R = OCH3) and H2L2 (R = OC2H5), and five heterodinuclear ZnII/LnIII complexes,
[Zn(L)(µ-CH3COO)Ln(NO3)2], containing [L1]2– and Gd3+, Tb3+, Er3+, or Yb3+ and
[L2]2– and Yb3+ have been synthesised and structurally characterised. The complexes
are isostructural and crystallise in the P21/n monoclinic space group. Zinc(ii)
is coordinated by the inner N2O2 donor set of the ligand and an oxygen of the
bridging acetate anion; the lanthanide(iii) ions possess an O9 coordination environment
involving the interaction with the ligand’s outer O4 donor set, two bidentate
nitrate ions, and the bridging acetate.
author:
- first_name: Norman
full_name: Kelly, Norman
last_name: Kelly
- first_name: Kathleen
full_name: Schnaars, Kathleen
id: '117735'
last_name: Schnaars
- first_name: Kerstin
full_name: Gloe, Kerstin
last_name: Gloe
- first_name: Thomas
full_name: Doert, Thomas
last_name: Doert
- first_name: Jan J.
full_name: Weigand, Jan J.
last_name: Weigand
- first_name: Karsten
full_name: Gloe, Karsten
last_name: Gloe
citation:
ama: 'Kelly N, Schnaars K, Gloe K, Doert T, Weigand JJ, Gloe K. New Heterodinuclear
Zn/Ln (Ln = Gd, Tb, Er, Yb) Complexes of Hexadentate N,N’-Bis(3-alkoxy-2-hydroxybenzyl)cyclohexane-1,2-diamines:
Synthesis and Structure*. Australian Journal of Chemistry. 2017;70(5):601-607.
doi:10.1071/ch16716'
apa: 'Kelly, N., Schnaars, K., Gloe, K., Doert, T., Weigand, J. J., & Gloe,
K. (2017). New Heterodinuclear Zn/Ln (Ln = Gd, Tb, Er, Yb) Complexes of Hexadentate
N,N’-Bis(3-alkoxy-2-hydroxybenzyl)cyclohexane-1,2-diamines: Synthesis and Structure*.
Australian Journal of Chemistry, 70(5), 601–607. https://doi.org/10.1071/ch16716'
bibtex: '@article{Kelly_Schnaars_Gloe_Doert_Weigand_Gloe_2017, title={New Heterodinuclear
Zn/Ln (Ln = Gd, Tb, Er, Yb) Complexes of Hexadentate N,N’-Bis(3-alkoxy-2-hydroxybenzyl)cyclohexane-1,2-diamines:
Synthesis and Structure*}, volume={70}, DOI={10.1071/ch16716},
number={5}, journal={Australian Journal of Chemistry}, publisher={CSIRO Publishing},
author={Kelly, Norman and Schnaars, Kathleen and Gloe, Kerstin and Doert, Thomas
and Weigand, Jan J. and Gloe, Karsten}, year={2017}, pages={601–607} }'
chicago: 'Kelly, Norman, Kathleen Schnaars, Kerstin Gloe, Thomas Doert, Jan J. Weigand,
and Karsten Gloe. “New Heterodinuclear Zn/Ln (Ln = Gd, Tb, Er, Yb) Complexes of
Hexadentate N,N’-Bis(3-Alkoxy-2-Hydroxybenzyl)Cyclohexane-1,2-Diamines: Synthesis
and Structure*.” Australian Journal of Chemistry 70, no. 5 (2017): 601–7.
https://doi.org/10.1071/ch16716.'
ieee: 'N. Kelly, K. Schnaars, K. Gloe, T. Doert, J. J. Weigand, and K. Gloe, “New
Heterodinuclear Zn/Ln (Ln = Gd, Tb, Er, Yb) Complexes of Hexadentate N,N’-Bis(3-alkoxy-2-hydroxybenzyl)cyclohexane-1,2-diamines:
Synthesis and Structure*,” Australian Journal of Chemistry, vol. 70, no.
5, pp. 601–607, 2017, doi: 10.1071/ch16716.'
mla: 'Kelly, Norman, et al. “New Heterodinuclear Zn/Ln (Ln = Gd, Tb, Er, Yb) Complexes
of Hexadentate N,N’-Bis(3-Alkoxy-2-Hydroxybenzyl)Cyclohexane-1,2-Diamines: Synthesis
and Structure*.” Australian Journal of Chemistry, vol. 70, no. 5, CSIRO
Publishing, 2017, pp. 601–07, doi:10.1071/ch16716.'
short: N. Kelly, K. Schnaars, K. Gloe, T. Doert, J.J. Weigand, K. Gloe, Australian
Journal of Chemistry 70 (2017) 601–607.
date_created: 2025-12-04T12:12:54Z
date_updated: 2025-12-04T12:19:28Z
department:
- _id: '985'
doi: 10.1071/ch16716
extern: '1'
intvolume: ' 70'
issue: '5'
language:
- iso: eng
page: 601-607
publication: Australian Journal of Chemistry
publication_identifier:
issn:
- 0004-9425
- 1445-0038
publication_status: published
publisher: CSIRO Publishing
quality_controlled: '1'
status: public
title: 'New Heterodinuclear Zn/Ln (Ln = Gd, Tb, Er, Yb) Complexes of Hexadentate N,N''-Bis(3-alkoxy-2-hydroxybenzyl)cyclohexane-1,2-diamines:
Synthesis and Structure*'
type: journal_article
user_id: '117735'
volume: 70
year: '2017'
...
---
_id: '62857'
abstract:
- lang: eng
text: 'The recovery of rare earth metals from secondary sources has attracted much
attention due to their ever expanding demand in the high-tech industry. The studies
reported here focus on the hydrometallurgical recovery of lanthanum and cerium
from spent fluid catalytic cracking (FCC) catalysts in a two-step process: leaching
with nitric acid and solvent extraction by tri-n-butyl phosphate (TBP) and di(2-ethylhexyl)phosphoric
acid (D2EHPA). The experiments show a high dissolution yield of about 93% lanthanum
and 42% cerium in a single leaching step with 2 M (126 g/L) HNO3 at 80 °C; only
11% aluminum has been dissolved simultaneously. In the subsequent solvent extraction
step the best results for this leach liquor could be achieved using a 1:1 mixture
of 25% (v/v) TBP (0.92 M) and 25% (v/v) D2EHPA (0.76 M) in n-decane without the
need for any pH adjustment. In that case La(III) and Ce(III) can be extracted
with 60% and 74% yield respectively in one stage from the majority of accompanying
matrix elements. In particular no extraction of Al(III) could be observed under
these conditions.'
author:
- first_name: M.
full_name: Wenzel, M.
last_name: Wenzel
- first_name: Kathleen
full_name: Schnaars, Kathleen
id: '117735'
last_name: Schnaars
- first_name: N.
full_name: Kelly, N.
last_name: Kelly
- first_name: L.
full_name: Götzke, L.
last_name: Götzke
- first_name: S. M.
full_name: Robles, S. M.
last_name: Robles
- first_name: K.
full_name: Kretschmer, K.
last_name: Kretschmer
- first_name: Phuc Nguyen
full_name: Le, Phuc Nguyen
last_name: Le
- first_name: Dang Thanh
full_name: Tung, Dang Thanh
last_name: Tung
- first_name: Nguyen Huu
full_name: Luong, Nguyen Huu
last_name: Luong
- first_name: Nguyen Anh
full_name: Duc, Nguyen Anh
last_name: Duc
- first_name: Dang Van
full_name: Sy, Dang Van
last_name: Sy
- first_name: K.
full_name: Gloe, K.
last_name: Gloe
- first_name: J. J.
full_name: Weigand, J. J.
last_name: Weigand
citation:
ama: 'Wenzel M, Schnaars K, Kelly N, et al. Hydrometallurgical Recovery of Rare
Earth Metals from Spent FCC Catalysts. In: Rare Metal Technology 2016.
Springer International Publishing; 2016. doi:10.1007/978-3-319-48135-7_4'
apa: Wenzel, M., Schnaars, K., Kelly, N., Götzke, L., Robles, S. M., Kretschmer,
K., Le, P. N., Tung, D. T., Luong, N. H., Duc, N. A., Sy, D. V., Gloe, K., &
Weigand, J. J. (2016). Hydrometallurgical Recovery of Rare Earth Metals from Spent
FCC Catalysts. In Rare Metal Technology 2016. Springer International Publishing.
https://doi.org/10.1007/978-3-319-48135-7_4
bibtex: '@inbook{Wenzel_Schnaars_Kelly_Götzke_Robles_Kretschmer_Le_Tung_Luong_Duc_et
al._2016, place={Cham}, title={Hydrometallurgical Recovery of Rare Earth Metals
from Spent FCC Catalysts}, DOI={10.1007/978-3-319-48135-7_4},
booktitle={Rare Metal Technology 2016}, publisher={Springer International Publishing},
author={Wenzel, M. and Schnaars, Kathleen and Kelly, N. and Götzke, L. and Robles,
S. M. and Kretschmer, K. and Le, Phuc Nguyen and Tung, Dang Thanh and Luong, Nguyen
Huu and Duc, Nguyen Anh and et al.}, year={2016} }'
chicago: 'Wenzel, M., Kathleen Schnaars, N. Kelly, L. Götzke, S. M. Robles, K. Kretschmer,
Phuc Nguyen Le, et al. “Hydrometallurgical Recovery of Rare Earth Metals from
Spent FCC Catalysts.” In Rare Metal Technology 2016. Cham: Springer International
Publishing, 2016. https://doi.org/10.1007/978-3-319-48135-7_4.'
ieee: 'M. Wenzel et al., “Hydrometallurgical Recovery of Rare Earth Metals
from Spent FCC Catalysts,” in Rare Metal Technology 2016, Cham: Springer
International Publishing, 2016.'
mla: Wenzel, M., et al. “Hydrometallurgical Recovery of Rare Earth Metals from Spent
FCC Catalysts.” Rare Metal Technology 2016, Springer International Publishing,
2016, doi:10.1007/978-3-319-48135-7_4.
short: 'M. Wenzel, K. Schnaars, N. Kelly, L. Götzke, S.M. Robles, K. Kretschmer,
P.N. Le, D.T. Tung, N.H. Luong, N.A. Duc, D.V. Sy, K. Gloe, J.J. Weigand, in:
Rare Metal Technology 2016, Springer International Publishing, Cham, 2016.'
date_created: 2025-12-04T12:15:35Z
date_updated: 2025-12-04T12:19:23Z
department:
- _id: '985'
doi: 10.1007/978-3-319-48135-7_4
extern: '1'
language:
- iso: eng
place: Cham
publication: Rare Metal Technology 2016
publication_identifier:
isbn:
- '9783319486161'
- '9783319481357'
publication_status: published
publisher: Springer International Publishing
quality_controlled: '1'
status: public
title: Hydrometallurgical Recovery of Rare Earth Metals from Spent FCC Catalysts
type: book_chapter
user_id: '117735'
year: '2016'
...