Structures and Spectral and Magnetic Properties of a Series of Carbacylamidophosphate Pentanuclear Lanthanide(III) Hydroxo Complexes

Abstract

A series of pentanuclear lanthanide complexes Ln 5 L 6 (μ-L) 4 (μ 3 -OH) 4 (μ 4 -OH) (Ln III = Nd, Dy, Ho, Er, Yb; L − = dimethyl N-benzoylamidophosphate ion, [C 6 H 5 C(O)−N−P(O)(OCH 3 ) 2 ] − ) was obtained by the reaction of sodium dimethyl N-benzoylamidophosphate with the corresponding lanthanide nitrates. The pentanuclear cores formed as a result of selfarrangement and their composition did not depend on the lanthanide ion. The complexes and sodium dimethyl Nbenzoylamidophosphate have been characterized by single-crystal X-ray diffraction. The absorption spectra of the complexes were measured at 300 and 4 K. The dysprosium and ytterbium complexes exhibited weak emission in the visible and IR regions, respectively. Temperature dependences of magnetic susceptibility (χ M ) of the dysprosium, holmium, and erbium compounds were studied. It was found that χ M vs T dependences were governed by the crystal field splitting effects with the Δ parameter being in the range 5−17 cm −1 . Slow magnetic relaxation was found for the dysprosium complex by ac magnetic measurements, while no significant out-of-phase signals were detected for holmium and erbium complexes.

Cadmium-Inspired Self-Polymerization of {LnIIICd2} Units: Structure, Magnetic and Photoluminescent Properties of Novel Trimethylacetate 1D-Polymers (Ln = Sm, Eu, Tb, Dy, Ho, Er, Yb)

“…The best correspondence between the experimental and calculated χ M T vs. T curves was achieved at Δ Tb = −15.9 cm −1 , zJ = −0.04 cm −1 for 3 ( g Tb = 3/2, R 2 = 6.1 × 10 −4 , which is defined as R 2 = Σ(χ T calc − χ T obs ) 2 /Σ(χ T obs ) 2 ), Δ Dy = 3.9 cm −1 for 4 ( g Dy = 4/3, R 2 = 6.7 × 10 −4 ), Δ Ho = 10.0 cm −1 , zJ = −0.18 cm −1 for 5 ( g Ho = 5/4, R 2 = 3.1 × 10 −3 ) and Δ Yb = 125 cm −1 , zJ = −0.73 cm −1 for 7 ( g Yb = 8/7, R 2 = 2.8 × 10 −4 ) ( Figure S8 ). The values of Δ Ln are quite close to the values, reported previously for Dy [ 37 ] and Ho [ 69 ], however, the correspondence between the experimental and calculated χ M T vs. T curve for 5 was not very good ( R 2 > 3 × 10 −3 ). Thus, simple model based on the above Hamiltonian cannot describe magnetic properties of these two complexes adequately.…”

“…With a temperature decrease, the χ M T values for 4 remain almost constant up to 100 K and then decrease with further lowering the temperature, reaching a value of about 8.5 cm 3 ·K·mol −1 at 2 K. The χ M T values for 3 , 5 , and 7 decreases with decreasing temperature over the entire temperature range, reaching minimum values of 6.3, 4.8 and 0.64 cm 3 ·K·mol −1 , respectively, at 2 K. Such magnetic behavior may be the result of depopulation of the excited Stark sublevels, corresponding to a number of crystal-field (CF for 3 , 6 ) or Kramers (KD for 4 and 7 ) doublets [ 65 ]. χ M T vs. T dependencies of 3 , 4 , 5 , and 7 could be simulated using a model based on the Hamiltonian (1), similarly to reported cases [ 65 , 66 , 67 , 68 , 69 ]. where Δ Ln is the parameter of electronic levels splitting by crystal field of axial symmetry, and J z is the operator of the full angular momentum of Ln III ion.…”

“… where Δ Ln is the parameter of electronic levels splitting by crystal field of axial symmetry, and J z is the operator of the full angular momentum of Ln III ion. Consideration of the molecular field ( z J term) [ 69 ] improved the fit in all cases. The simulation was performed using Mjollnir software [ 69 , 70 , 71 , 72 ] as described previously [ 37 ].…”

“…Consideration of the molecular field ( z J term) [ 69 ] improved the fit in all cases. The simulation was performed using Mjollnir software [ 69 , 70 , 71 , 72 ] as described previously [ 37 ].…”

New Luminescent Lanthanide Tetrakis‐Complexes NEt4[LnL4] Based on Dimethyl‐N‐Benzoylamidophosphate

“…Dimethyl-N-benzoylamidophosphate was shown to be a good lanthanide luminescence sensitizer [17,38] and a versatile ligand, which can bind metal ions in different modes. [39] In particular, tetrakis-complexes Cs[LnL 4 ] exhibited high thermal stability and bright luminescence. [17] It was intriguing to investigate if the Cs + ion in Cs[LnL 4 ] can be replaced by an organic cation and how this change will influence the properties of the complexes.…”