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

Crystal structure of di-μ-acetato-κ4 O:O'-bis{(acetato-κ2 O,O')tetra-aqua-[1-(pyridin-2-yl-methylidene-κN)-2-(pyridin-2-yl-κN)hydrazine-κN 1]lanthanum(III)} dinitrate hemihydrate

In the binuclear title complex, [La2(C2H3O2)4(C11H10N4)(H2O)4](NO3)2·0.5H2O, the two lanthanum ions are nine coordinate in a distorted trigonal-prismatic geometry. Each LaIII ion is bonded to three N atoms of the Schiff base, 1-(pyridin-2-yl)-2-(pyridin-2-yl-methyl-ene)hydrazine and is coordinated by one acetate group, which acts in η 2-bidentate mode and two acetate groups that act in μ 2-mode between the two LaIII ions. Two η 1-water mol-ecules complete the coordination sphere. All bond lengths in the coordination environment of the LaIII ion are slightly larger than those observed in the isostructural NdIII and SmIII complexes. The LaIII⋯LaIII distance is 4.6696 (6) Å. In the crystal, extensive O-H⋯O hydrogen-bonding inter-actions involving the coordinated water mol-ecules and the non-coordinating nitrate anions, as well as the oxygen atoms of the acetate groups, generate an overall three-dimensional supra-molecular network.

New lanthanum (III) complexes containing azaphosphor β-diketon and diimine ligands: Synthesis, crystallography, morphology properties, DNA binding, DNA cleavage, and DFT calculation

Two octa-coordinated lanthanum (III) complexes of deprotonated azaphosphor β-diketon and diimine ligands, [LnL3Q] (L = [Cl2CHC(O)NP(O)(NC6H12)2], Q = Phen (C1) and Bipy (C2)), were synthesized and characterized by elemental analysis, IR, and NMR spectra. X-ray crystallography revealed a distorted tetragonal antiprism LaO6N2 coordination geometry around the lanthanum atom in both compounds. Nano-sized complexes (Ć1 and Ć2) were synthesized via a sonochemical process and analyzed using SEM and XRPD. TGA-DTA analysis were performed on complexes in both bulk and nano scales. Redox behavior was also examined by cyclic voltammetry. The interaction between the complexes and calf thymus DNA (ct-DNA) was investigated using UV-Vis spectroscopy, fluorescence titration, viscosity measurements, and gel electrophoresis. C2 and Ć2 likely intercalate between DNA base pairs through van der Waals forces and hydrogen bonding, whereas C1 and Ć1 interact with DNA via groove binding. Further, result indicated the apparent association constant (Kapp) in the range of 4.53 × 104 M-1-26.86 × 104 M-1 with the highest value for nanocomplex Ć2. Fluorescence studies revealed dynamic and static quenching for C1, while the other compounds followed a static quenching process. Hirshfeld surface analysis and the NCI method were employed to demonstrate how non-covalent interactions influence the crystal packing through intermolecular interactions.

Lanthanide Single-molecule Magnets: Synthetic Strategy, Structures, Properties and Recent Advances

Single-molecule magnets (SMMs) show wide potential applications in the field of ultrahigh-density storage materials, quantum computing, spintronics, and so on. Lanthanide (Ln) SMMs, as an important category of SMMs, open up a promising prospect due to their large magnetic moments and huge magnetic anisotropy. However, the construction of high performance for Ln SMMs remains an enormous challenge. Although remarkable advances are focused on the topic of Ln SMMs, the research on Ln SMMs with different nuclear numbers is still deficient. Therefore, this review summarizes the design strategies for the construction of Ln SMMs, as well as the metal skeleton types. Furthermore, we collect reported Ln SMMs with mononuclearity, dinuclearity, and multinuclearity (three or more Ln spin centers) and the SMM properties including energy barrier (U_eff ) and pre-exponential factor (τ₀ ) are described. Finally, Ln SMMs with low-nuclearity SMMs, especially for single-ion magnets (SIMs), are highlighted to understand the correlations between structures and magnetic behavior of the detail SMM properties are described. We expect the review can shed light on the future developments of high-performance Ln SMMs.

Crystal structure of caesium dimethyl-N-benzoyl-amido-phosphate monohydrate

The caesium salt of dimethyl-N-benzoyl-amido-phosphate, namely, aqua-[di-meth-yl (N-benzoyl-amido-κO)phospho-nato-κO]caesium, [Cs(C9H11NO4P)(H2O)] or CsL·H2O, is reported. The compound crystallizes in the monoclinic crystal system in the P21/c space group and forms a mono-periodic polymeric structure due to the bridging function of the dimethyl-N-benzoyl-amido-phosphate anions towards the caesium cations.

New luminescent lanthanide tetrakis - complexes NEt4[LnL4] based on dimethyl-N-benzoylamidophosphate

The new lanthanide dimethyl-N-benzoylamidophosphate (HL) based tetrakis-complexes NEt 4 [LnL 4 ] (Ln 3+ = La, Nd, Sm, Eu, Gd, Tb, Dy) are reported. The complexes are characterized by means of NMR, IR, absorption, and luminescent spectroscopy as well as by elemental, X-Ray, and thermal gravimetric analyses. The phenyl groups of the four ligands of the complex anion are directed towards one side, while the methoxy groups are directed in the opposite side, which makes the complexes under consideration structurally similar to calixarenes. The effect of changing the alkali metal counterion to the organic cation NEt 4 + on the structure and properties of the tetrakis-complex [LnL4]- is analyzed. The complexes exhibit bright characteristic for respective lanthanides luminescence. Rather high intensity of the band of 5 D 0 → 7 F 4 transition, observed in the luminescence spectrum of NEt 4 [EuL 4 ], is discussed based on theoretical calculations.

A Discrete 3d-4f Metallacage as an Efficient Catalytic Nanoreactor for a Three-Component Aza-Darzens Reaction

The exploration and development of coordination nanocages can provide an approach to control chemical reactions beyond the bounds of the flask, which has aroused great interest due to their significant applications in the field of molecular recognition, supramolecular catalysis, and molecular self-assembly. Herein, we take the advantage of a semirigid and nonsymmetric bridging ligand (H₅L) with rich metal-chelating sites to construct an unusual and discrete 3d-4f metallacage, [Zn₂Er₄(H₂L)₄(NO₃)Cl₂(H₂O)]·NO₃·xCH₃OH·yH₂O (Zn₂Er₄). The 3d-4f Zn₂Er₄ cage possesses a quadruple-stranded structure, and all of the ligands wrap around an open spherical cavity within the core. The self-assembly of the unique cage not only ensures the structural stability of the Zn₂Er₄ cage as a nanoreactor in solution but also makes the bimetallic lanthanide cluster units active sites that are exposed in the medium-sized cavity. It is important to note that the Zn₂Er₄ cage as a homogeneous catalyst has been successfully applied to catalyze three-component aza-Darzens reactions of formaldehyde, anilines, and α-diazo esters without another additive under mild conditions, displaying better catalytic activity, higher specificity, short reaction time, and low catalyst loadings. A possible mechanism for this three-component aza-Darzens reaction catalyzed by the Zn₂Er₄ cage has been proposed. These experimental results have demonstrated the great potential of the discrete 3d-4f metallacage as a host nanoreactor for the development of supramolecular or molecular catalysis.

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)

A series of heterometallic carboxylate 1D polymers of the general formula [Ln^IIICd₂(piv)₇(H₂O)₂]_n·nMeCN (Ln^III = Sm (1), Eu (2), Tb (3), Dy (4), Ho (5), Er (6), Yb (7); piv = anion of trimethylacetic acid) was synthesized and structurally characterized. The use of Cd^II instead of Zn^II under similar synthetic conditions resulted in the formation of 1D polymers, in contrast to molecular trinuclear complexes with Ln^IIIZn₂ cores. All complexes 1–7 are isostructural. The luminescent emission and excitation spectra for 2–4 have been studied, the luminescence decay kinetics for 2 and 3 was measured. Magnetic properties of the complexes 3–5 and 7 have been studied; 4 and 7 exhibited the properties of field-induced single-molecule magnets in an applied external magnetic field. Magnetic properties of 4 and 7 were modelled using results of SA-CASSCF/SO-RASSI calculations and SINGLE_ANISO procedure. Based on the analysis of the magnetization relaxation and the results of ab initio calculations, it was found that relaxation in 4 predominantly occurred by the sum of the Raman and QTM mechanisms, and by the sum of the direct and Raman mechanisms in the case of 7.

Terbium-fluorido cluster: an energy cage for photoluminescence

We report here that energy migration during luminescence can be extremely minimized by caging the fluorescent centers in a molecular cluster of [Tb6(μ3-F)8(piv)10(Hpiv)4DMF]·xDMF·yH2O 1. Experimental and theoretical simulations reveal that bonding terbium with fluoride is the key to reducing the non-radiative multi-phonon relaxation processes, which is disparate to the common hydroxy-based lanthanide clusters.

3D lanthanide-coordination frameworks constructed by a ternary mixed-ligand: crystal structure, luminescence and luminescence sensing

Highly stable 3D Ln-MOFs were constructed by a ternary mixed-ligand. The Sm/Dy-MOFs present dual-emission while the Tb/Eu-MOFs exhibit red/green MC emission. The detection of quercetin and Fe³⁺ion was realized based on the luminescence Eu-MOF under the excitation of 358 nm.