A new series of 3D lanthanide phenoxycarboxylates: synthesis, crystal structure, magnetism and photoluminescence studies
A new series of 3D lanthanide (Ln) frameworks has been synthesized with the general formula [{Ln( L )(H 2 O)}·H 2 O] n (where Ln = La( 1 ), Tb( 2 ) and Dy( 3 ); L = (HO)OC 6 H 2 (CH 2 COO) 2 ; H 3 L = 2,5-dihydroxy-1,4-benzenediacetic acid = DHBDA). All the crystals were analyzed by single crystal X...
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Veröffentlicht in: | CrystEngComm 2021-01, Vol.23 (23), p.4143-4151 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | A new series of 3D lanthanide (Ln) frameworks has been synthesized with the general formula [{Ln(
L
)(H
2
O)}·H
2
O]
n
(where Ln = La(
1
), Tb(
2
) and Dy(
3
);
L
= (HO)OC
6
H
2
(CH
2
COO)
2
; H
3
L
= 2,5-dihydroxy-1,4-benzenediacetic acid = DHBDA). All the crystals were analyzed by single crystal X-ray diffraction. The Ln ions are octa-coordinated having the square antiprism geometry with the
D
4d
symmetry and connected along the crystallographic
a
-axis forming a zigzag chain. These chains are further connected by the ligands in three-dimensional crystallographic space. Compounds
2
and
3
were subjected to variable temperature magnetic susceptibility measurements and photoluminescence studies. Magnetic studies reveal that compound
2
possesses antiferromagnetic coupling whereas compound
3
shows ferromagnetic interaction at temperatures above
ca.
40 K. The emission spectra of compounds
2
and
3
combine the intra-4f emission of the Ln ions with that of the ligand, depending on the selected temperature, pointing out that the energy transfer processes are thermally activated. In addition, compound
2
presented an invariant
5
D
4
lifetime behaviour at temperatures between 15 and 300 K. Theoretical analysis showed that the long-lived lifetimes of the free ligand's excited states and the intramolecular energy transfer rate invariability are responsible for such abnormal behaviour.
A new series of 3D Ln-carboxylates was synthesized, where the Tb one shows antiferromagnetic coupling and the Dy one shows ferromagnetic interaction, and with emission spectra combining the intra-4f emission of the Ln ions and that of the ligand. |
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ISSN: | 1466-8033 1466-8033 |
DOI: | 10.1039/d1ce00228g |