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A series of lanthanide(III) oxamate complexes of formula Na[Eu(4-HOpa)4(H2O)]∙2H2O (1), Na[Gd(4-HOpa)4(H2O)]∙2H2O (2), Na[Dy(4-HOpa)4(H2O)]∙2H2O (3), and Na[Ho(4-HOpa)4(H2O)]∙2H2O (4) (4-HOpa = N-4-hydroxyphenyloxamate) were synthesized and characterized. The crystal structures of complexes 1–4, as well as the oxamate ligand in the ethyl ester acid form (Et[4-HOpa]), were elucidated by single crystal X-ray diffraction. 1–4 are isostructural, and they crystallize in the P21/n space group of the monoclinic system. The crystal structures of 1–4 consist of mononuclear lanthanide(III) complex anions, [Ln(4-HOpa)4(H2O)]− (Ln = Eu3+, Gd3+, Dy3+, and Ho3+), coordinated sodium(I) countercations, and crystallization water molecules, resulting in a 2D NaILnIII supramolecular coordination network. The coordination sphere of Ln3+ ions consists of square-face capped square antiprism (SAPRS-9). Magnetic properties were investigated for 1–4 in the 2–300 K temperature range using polycrystalline samples. Complex 2 exhibits an unusual and rare slow-relaxation of the magnetization for Gd3+ ions under DC applied field of 1.0 kOe, behaving as a field-induced single-ion magnet as occurs for the Dy3+ complex 3. The Eu3+ complex 1 has a nonmagnetic ground state, while the Ho3+ compound 4 behave as a paramagnet, and do not exhibit relaxation of the magnetization with or without an applied field.

Lanthanide pyrrole-2-carboxylates [{Ln(L)3(H2O)2}·H2O]n (Ln = Eu, Gd, Tb) were synthesized and investigated using single crystal X-ray diffraction and optical spectroscopy (luminescence, luminescence excitation and vibrational IR spectra). The europium pyrrole-2-carboxylate crystallizes as a 2D network structure in the P21/c space group. The Eu3+ coordination polyhedron formed by five carboxylic groups and two water molecules can be described as a distorted single-capped square antiprism. The luminescence spectra indicate a low symmetry of the charge distribution around the Ln3+ ion that corresponds to the C1 symmetry of the coordination environment of Eu3+ ion in the [{Eu(L)3(H2O)2}·H2O]n crystal lattice. The low-energy ligand–metal charge transfer (LMCT) state was identified in the europium compound. The shortening of the 5D0 (Eu3+) lifetime in the 230–295 K temperature region, when the compound is heated from 77 to 295 K, and the low luminescence intensity of the europium pyrrole-2-carboxylate are caused by the participation of the LMCT state in quenching processes. The energy of activation determined for the 5D0 – LMCT crossover is 3900 ± 100 cm−1.

Homo-trinuclear [Zn3(L)(μ2-OAc)2(H2O)].CH2Cl2 (1) and hetero-pentanuclear [Zn4(L)2Eu(NO3)3(H2O)] (2) and [Zn4(L)2Nd(NO3)3(H2O)]·CH3CH2OH (3) complexes containing a coumarin-skeleton bis(salamo) ligand H4L, were successfully prepared and characterized via the means of elemental analyses, single crystal X-ray crystallography, FT-IR, UV–Vis absorption spectroscopy and Hirshfeld surfaces analyses. Complex 1 is a 1:3 ((L)4−:ZnII) structure, and complexes 2 and 3 are 2:4:1 ((L)4−:ZnII:LnIII) structure. All ZnII atoms in complexes 1–3 occupied the N2O2 sites are five-coordinated with geometries of slightly distorted tetragonal pyramid and trigonal bipyramid. Rare earth metal (EuIII and NdIII) atoms are both coordinated with phenolic oxygen atoms, and eight-coordinated with the square antiprism geometries in complexes 2 and 3. Water molecules as coordinating solvents participate in the coordination. Supra-molecular structures are built by C H…π and hydrogen bonding interactions in complexes 1–3. Moreover, Hirshfeld surfaces analyses of complexes 1–3 were also analysed in detail. Most important of all, luminescences of complexes 1–3 were discussed.

Three new LnIII-MOFs, {[Dy1.5(TAPB)1.5(DMF)]·9DMF}n (Ln = Dy (1), Er (2), Ho (3); TAPB = 4, 4′, 4″-(triazine‑2, 4, 6‑triyl‑tris‑(benzene‑4, 1-diyl)) tribenzoate), have been synthesized via a solvothermal method by using a trigonal N-containing tricarboxylate as the ligand. The coordination geometries around the central metal ions in the MOFs exhibit different deviations from ideal square antiprism (D4d symmetry) because of the coordinated solvent molecules. The ac magnetic susceptibility data is consistent with single chain magnet behavior for Dy(III) and Er(III) complexes, which have been studied by the noncritical scaling theory.

Four new coordination polymers based on the use of the [Cr(pyim)(C2O4)2]− species as a metalloligand, namely [LiCr(pyim)(C2O4)2(MeOH)]n (1), {[CaCr2(pyim)2(C2O4)4]·2MeOH}n (2), {[SrCr2(pyim)2(C2O4)4(H2O)]·0.45MeOH·4.55H2O}n (3) and {[CdCr2(pyim)2(C2O4)4]·MeOH}n (4) [pyim = 2-(2′-pyridyl)imidazole] have been synthesized and characterized by elemental analyses, IR spectra and X-ray diffraction on single crystals. Complex 1 is a neutral heterobimetallic chain where the tris(chelated) chromium(III) unit acts as a bis-bidentate ligand towards {Li(MeOH)}+ fragments through its two oxalate ligands, each lithium ion being five-coordinate in a intermediate surrounding between square pyramidal and trigonal bipyramidal. The structure of 2 consists of neutral oxalato-bridged chromium(III)-calcium(II) double chains of single chirality [all the tris(chelated) chromium centres have the same chirality either Λ or λ] and methanol molecules of crystallization. Each calcium ion in 2 exhibits a square antiprism environment which is built by four bidentate oxalate ligands from four [Cr(pyim)(C2O4)2]− units. Neutral oxalato-bridged chromium(III)-strontium(II) double chains also occur in 3 with methanol and water molecules of crystallization, each alkaline-earth cation being nine-coordinate in a monocapped square antiprism environment which is defined by a water molecule and eight oxalate-oxygens from four [Cr(pyim)(C2O4)2]− units. The CrIII2MII2 loops [M = Ca (2) and Sr (3)] within each double chain are planar. The structure of 4 is also made of neutral oxalato-bridged chromium(III)-cadmium(II) double chains but in contrast to 2 and 3, the chirality of the tris(chelated) chromium unit in 4 is alternated in each loop and the adjacent CrIII2CdII2 loops are not planar but form a dihedral angle of 84.8°. The potential use of the [Cr(pyim)(C2O4)2]− entity as a metalloligand in designing heterobimetallic compounds is analyzed and discussed.

The reaction of the lanthanide(III) β-diketonate salt (Dy(beac)3·2H2O) with a bidentate chelating ligand 5-(2-hydroxy-5-methylbenzylidene)-8-hydroxylquinoline (HL) afforded the tetranuclear Dy(III) cluster, [Dy4(μ3-OH)2L6(beac)4]·10CH3CN (1). The elemental analysis (EA), powder X-ray diffraction (PXRD), single-crystal X-ray diffraction and magnetic properties of 1 have been characterized. The X-ray structural analysis reveals that cluster 1 contains one Dy4 center with a rhombus-shaped arrangement, and each Dy(III) ion of 1 is located in a distorted square antiprism geometrical configuration. Magnetic properties study indicate that 1 shows single-molecule magnet behavior with larger energy barrier (ΔE/kB) of 78.3 K and τ0 = 4.4 × 10−7 s.

In the work, the first principles calculation and low temperature spectra were utilized to investigate the modification on Nd3+ clusters in SrF2 crystal. The results show that structures of the clusters vary greatly and it depends on the ionic radius of rare-earth La3+, Nd3+, Gd3+ and Y3+. The cubic sublattice centers are stable in large size rare-earth La3+- and Nd3+-doped SrF2, and the square antiprism centers are more stable in smaller size Gd3+- and Y3+-doped crystals. It suggests that the square antiprism clusters become more stable with decreasing ionic radius in going from La3+, Nd3+, Gd3+ to Y3+, while the cubic sublattice centers become unstable. Based on the results, the mixed [Nd3+-La3+] and [Nd3+-Gd3+] clusters are also calculated. Stability of square antiprism clusters is improved with increasing concentration of Gd3+ in [Nd3+-Gd3+] clusters, and that weakened when codoped with La3+. The results reveal that characteristics of the mixed centers depend on species and contents of the ingredient rare-earth ions. Local environment of the active ions could therefore be modified by codoping the other rare-earth ions, which agreed well with the tunable absorption and emission spectra of Nd3+:SrF2 modified by La3+, Gd3+ and Y3+. The varied cluster structures provide us a methodology towards designing of new rare-earth-doped fluoride materials.

Two mononuclear Dy(III) compounds, [Dy(fbta)3(HCOOH)2] (1) and [Dy(fbta)4]∙C5H6N (2) (fbta ​= ​3-(4-Fluorobenzoyl)-1,1,1-trifluoroacetone), were synthesized based on different pH control reagents including HCOOH and C5H5N. Dy(III) ions in compounds 1 and 2 belong to square antiprism (D4d) configurations with DyO8 coordination environments. Two coordinated carboxyl oxygen atoms of two different HCOOH molecules in 1 are replaced by two coordinated oxygen atoms of one β-diketone anion ligand in 2. One protonated C5H6N guest as a monovalent cation is found to reside in 2, resulting in charge balance. The different synthetic conditions have an important in determining the final structures and magnetic behaviors in 1 and 2. Compound 1 displays SMM behavior under zero dc field, while compound 2 shows neither peak nor frequency dependence at zero dc field. The efficient ON/OFF switching of SMM behavior was interpreted by the theoretical calculations of quantum tunneling of magnetization (QTM) time.

In this work, we synthesized the {tris(thenoyltrifluoroacetone)pyrazino[2,3-f][1,10]phenanthroline}europium (III) complex and studied its thermal emission quenching. The crystal structure of the [Eu(tta)3(pyphen)] complex show that the europium (III) ion occupies a distorted D4d symmetry of a square antiprism site. The complex shows an absolute emission quantum yield of 43.3 ± 1.2. The temperature dependence of the photophysical properties of the complex was evaluated and indicates that the complex has potential to be applied as a lifetime based luminescent thermometer. The quenching of the luminescence as a function of temperature occurs due the energy back-transfer from the emitter state to the ligand centered triplet state. The temperature induced blue-shift in the 5D0 → 7F0 transition band indicates the presence of the electron-phonon coupling in this complex.

A cerium(III) complex, [Ce2(NA)6(H2O)4] (1) and an erbium(III) complex, [Er2(2-AMB)6(H2O)4]·3H2O (2), where NA = nicotinic acid and 2-AMB = 2-aminobenzoic acid, have been prepared and characterized by IR spectroscopy, thermogravimetric analysis and X-ray crystallography. The single crystal analysis reveals that both complexes are dinuclear. In 1, the two cerium(III) ions are bridged by carboxylate groups of four nicotinate ligands. Each cerium atom in 1 is nine-coordinate and exhibits a distorted monocapped square antiprism geometry. The Ce(III) ions are coordinated by seven oxygen atoms of the carboxylate groups and two oxygen atoms of water molecules. In 2, each Er(III) ion is eight-coordinated adopting a distorted ErO8 dodecahedral geometry. The Er(III) ions are bound to four oxygen atoms of the chelating carboxylate ligands, to one oxygen each from the two bridiging carboxylates, and two oxygen atoms of water molecules. In 2 there is an intramolecular hydrogen bond forming a six-membered ring between the NH2 group and one of the carboxylate oxygens in each of the six 2-AMB ligands. In the crystal packing, the molecules of 1 and 2 are associated through O(or N)–H⋯O and O–H⋯N hydrogen bonds. In 2 the intermolecular hydrogen bonding results in a 3D supramolecular network structure.

A solid state Eu3+ complex with dehydroacetic acid (DHA) has been synthesized and characterized by elemental analysis, UV–visible, FT-IR, FT-Raman, powder and single-crystal X-ray diffraction and optical spectroscopy studies. The complex has formula [Eu(DHA)2(H2O)5]NO3 with DHA = C8H7O4−, where the europium ions is in monocapped distorted square antiprism environment with coordination number nine. Its photophysical properties have been analyzed in terms of its molecular structure and DFT calculations performed for the representative crystal fragment including Eu3+ and two DHA ligands. The luminescence and dynamics of the excited states depopulation have been studied using femtosecond laser excitation. The energy transfer mechanism between the ligand and Eu3+ electronic energy levels has been proposed. The obtained results have been compared to those of Gd3+ dehydroacetic derivative.

The synthesis, crystal structures, and magnetic properties of a nonanuclear dysprosium complex [Dy9(μ3-OH)8(μ4-OH)2(N3)8{(py)2C(OCH3)O}8](OH)·4H2O (1, (py)2C(OCH3)OH = the hemiacetal form of di-2-pyridyl ketone) and a tetranuclear dysprosium complex [Dy4(μ4-O)(μ-N3)2(μ-OCH3)2(L)4](OH)2·3.5CH3OH (2, HL = 2-(benzothiazol-2-yl-hydrazonomethyl)-6-methoxyphenol) have been prepared and structural characterization. Nine DyIII ions in 1 form a sandglass with the eight DyIII atoms at the apexes and one DyIII ion located at the center of a square antiprism formed by eight DyIII ions, while four DyIII ions in 2 form an irregular tetrahedron. Complexes 1 and 2 have been investigated by direct current (dc) and alternating current (ac) susceptibility measurements. The ac susceptibility studies revealed that complexes 1 and 2 exhibit slow magnetic relaxation. Moreover, complex 2 shows two-step thermal magnetic relaxation with their energy barriers of about 15 K and 2.68 K, respectively. The orientations of the magnetic anisotropy of DyIII ions in 1 and 2 were also estimated by electrostatic calculations.

The new lanthanide coordination compounds of general formula [LnL3Q], where Ln = Eu, Gd, Tb; L = dimethyl-N-trichloroacetylamidophosphate and Q = 2-(1,3,4-oxadiazole-2-yl)pyridine, have been synthesized and isolated in crystalline state with the purpose of finding new interesting optical materials. X-ray data reveal that complexes have molecular structure with numerous Van-der-Vaals contacts between molecules. All the ligands are coordinated in bidentate chelate manner, coordination polyhedron was interpreted as distored square antiprism (CN 8). The obtained complexes were investigated by means of IR, absorption and luminescence spectroscopy as well and thermal gravimetric analysis. It was found that complex [TbL3Q] is resistant to temperature of 200 °C. The Eu3+ and Tb3+ complexes exhibit bright metal-centered emission with decay time 1.65 and 1.74 ms respectively. Intrinsic quantum yield for [EuL3Q] equals 85% that is one of the highest values, known to date for CAPh based europium complexes.

Two isostructural Dy(III) and Tb(III) complexes based on 5-azotriazolyl salicylic acid (H3ATSA) ligand of [Ln(HATSA)(OAc)(H2O)2]·4H2O [Ln = Dy (1), Tb (2)] have been synthesized and characterized by single-crystal X-ray diffraction analysis. Each Dy(III) and Tb(III) ion coordinates to eight oxygen atoms to form an eight-coordinated square antiprism geometry. The two-dimensional coordinated layers are further linked to a stable three-dimensional supramolecular network by π-π stacking interactions. The fluorescent and magnetic properties of 1 and 2 were investigated and discussed. The solid sample of 2 shows four characteristic emission bands at 490, 546, 585 and 622 nm for Tb(III) ion under excitation at 313 nm. The alternating current (ac) magnetic susceptibility for 1 shows an increase of frequency-dependent.

In this context, three isomorphic compounds were obtained, namely, [Ln2(L)2(NO3)4(H2O)2]·2CH3OH (Ln = Dy (1), Tb (2) and Er (3), HL = N′-(2-Hydroxybenzoyl) pyridine-2-carbohydrazonamide). In these compounds, LnIII ion locates in N2O7 coordination environment, forming a monocapped square antiprism configuration (C4v). Furthermore, two L− ligands coordinate to two LnIII centers in an antiparallel or “head-to-tail” fashion with tridentate unit and monodentate phenol-O−, resulting in a center of symmetry with LnIII⋯LnIII distances (intramolecular) of 6.751 A for 1, 6.708 A for 2 and 6.723 A for 3, respectively. Magnetic measurement reveals that 1 shows frequency-dependent out-of-phase (χ″) signals under a direct-current (dc) field, exhibiting single-molecule magnet (SMM) behavior with the anisotropy energy barrier (Ueff) of 16.0 K and the pre-exponential factor value (τ0) of 1.0 × 10−6 s. In addition, the luminescence properties of 1 and 2 were studied. Moreover, the semiconductor behaviors of 1–3 have been investigated by experimental measurements of UV−vis spectroscopy.

In this study, one new rare-earth lanthanum(Ⅲ) metal-organic coordination polymer {[La(L)1.5(H2O)(DMF)]∙DMF}n (H2L = 4,4’-(diethynylanthracene-9,10-diyl) dibenzoic acid) labeled as La-CP was successfully constructed via a solvothermal process. Structure analysis of the obtained La-CP revealed that it crystallized in the triclinic space group P-1, in which each La3+ ion was coordinated to eight oxygen atoms to form a distorted square antiprism geometry. It was important to observe π-π stacking between adjacent ligand moieties of La-CP with face-to-face distances of 3.385 and 3.447 A, endowing charge carriers with the possibility of through-space transport. The optical band gap of 2.23 eV evaluated from the UV-vis diffuse reflectance spectrum, coupled with electronic band structure calculation, provided reliable evidence of its potential semiconductor characteristic. In addition, La-CP exhibited a yellow fluorescence emission and a comparable quantum yield of 1.81% to that of free ligand H2L in terms of its optical properties. This work not only expands the list of rare-earth lanthanide coordination polymers but also offers useful guidance for materials design and related properties modulation of coordination polymers to some extent.

The first complexes of Ce(IV)fluoride in solution have been observed and studied by 19F{1H}, 1H NMR and IR spectroscopy in saturated solutions of CeF4*H2O in Me2SO diluted by CH3CN or CH2Cl2. On the base of analysis of the temperature dependence of the 19F{1H} NMR spectra and the assumption that the usual for the solid Ce(IV) fluorocomplexes square antiprism coordination polyhedron is retained in the solution, the conclusion has been made that dynamic equilibrium between the molecular adduct [CeF4(Me2SO)4] and ionic forms [CeF3(Me2SO)5]+ and [CeF5(Me2SO)3]− exists in solution, including geometric isomers. The statistical probability of formation of [CeF4(Me2SO)4] and [CeF5(Me2SO)3]− stereoisomers has been calculated. Quantum chemical calculations of the structures of some visually distinguishable isomers of [CeFn(Me2SO)8-n]4-n (n=3–5) and [CeF4(Me2SO)3(H2O)] showed their thermodynamic stability. The experimental IR spectrum of the solution is in a good agreement with calculated spectra of [CeFn(Me2SO)8-n]4-n and [CeF4(Me2SO)3(H2O)] stable complexes.

We investigated the viscosities of several series of FeB-based bulk-glass-forming melts with rare earth element additions. The viscosity discontinuity generally exists in the melts. With the rare earth element addition, such dynamic transition becomes indistinct. By the concept of superheated liquid fragility, the addition of rare earth elements significantly reduces the degree of the dynamic transition F from larger than 1 to less than 1. A generally negative correlation between F and GFA has been demonstrated. By conducting the ab initio molecular dynamics simulations, the competition between the formations of square antiprism structures and the stable rare-earth-contained polyhedra around B atoms have been found to determine the F value, as well as the GFA of FeB-based liquids. This work demonstrates the mechanism underlying which the glass-forming ability of alloys is greatly improved by rare earth elements, and provides a novel route to obtain bulk-size Fe-based glasses.

The lanthanide-doped materials have been widely used. The well shielded f orbitals make the f-f transitions be sharp lines and non-tunable which are hurdles to the generation of ultrashort lasers. In the work, the spectral properties of neodymium-doped fluorite crystal are modulated to be varied significantly with the compositions of the crystal. The first principles calculation is combined and the results show that there exist two types of centers of cubic and square antiprism sublattice clusters. The concentrations of the centers could be tuned in large scale by adjusting the compositions of the host. Then tunable broadband photoluminescence is obtained which is promising for the generation of ultrashort pulses. The designing of new ultrafast laser materials is highly expected in the rare-earth-doped fluoride crystals.

A series of zirconium (IV) Schiff-base complexes formulated as [Zr (L x ) 2 ] and [Zr (L x ′) 2 ] were synthesized by reaction of tetradentate salicylaldimine Schiff-base ligands with [Zr (acac) 4 ] in methanol. These ligands are as follows: H 2 L x and H 2 L x ′ (x = x′ = 1,2,3,4). The new complexes have been characterized using FT-IR, l H NMR, 13 C{ 1 H} NMR spectroscopic techniques, elemental analyses (CHN) and the crystal structure of Zr (L 3 ) 2 , Zr (L 1′ ) 2 and Zr (L 3′ ) 2 were determined by X-ray crystallography. The crystal structure analysis revealed that the coordination environment of the metal in all complexes is eight-coordinate occupied by N 2 O 2 sets of the coordinated ligands in distorted square-antiprism geometry. The in vitro biological screening effects of the synthesized compounds were tested against different microbial kinds and the zirconium (IV) complexes exhibit antimicrobial activity.

The crystal structure of new monoclinic molybdate BaSm 2 (MoO 4 ) 4 is refined in monoclinic unit cell C 2/ m with cell parameters a = 5.29448 A, b = 12.7232 A, c = 19.3907 A, β = 91.2812°, V = 1305.89 A 3 . The crystal structure consists of the SmO 8 square antiprism joined with each other by the edges forming a 2D layer perpendicular to the c -axis. MoO 4 tetrahedra join SmO 8 by nodes and also participate in layer formation, and Ba ions are located between these layers. The lattice dynamics is theoretically calculated on the base of the crystal structure data. The Raman spectra are recorded and analyzed in comparison with theoretical calculations. The discrepancy between the experimental and calculated Raman frequencies does not exceed 2 cm −1 for the most of Raman lines. The luminescence spectra of Sm 3+ ions, which are positioned in the lowest local symmetry site C 1 , strongly differ from those detected for another molybdate crystal, β-RbSm(MoO 4 ) 2 , with the C 2 local symmetry. The 4 G 5/2 → 6 H 9/2 band is dominating in the BaSm 2 (MoO 4 ) 4 luminescence.

Heterotrinuclear 3d-4f complexes with a naphthalenediol-based acyclic bis(salamo)-type ligand have been synthesized and structurally characterized. Spectral titrations clearly show that the heterotrinuclear complexes [Zn2(L)La(OAc)3] (1), [Zn2(L)Ce(OAc)3] (2) and [Zn2(L)Dy(OAc)3(CH3OH)]·CH2Cl2 (3) are acquired by the substitution reaction of the obtained homotrinuclear Zn(II) complex with 1 equiv. of Ln(NO3)3 (Ln3+=La3+, Ce3+ and Dy3+). Two Zn(II) ions are penta- and hexa-coordinated with geometries of distorted tetragonal pyramid and octahedron. La(III) ion is deca-coordinated, adopting a distorted bicapped square antiprism geometry. Ce(III) ion is nona-coordinated with geometry of distorted capped square antiprism as well as Dy(III) ion. The different coordination modes of acetate ions in complexes 1, 2 and 3 lead to different coordination numbers of the lanthanide(III) ions. Furthermore, the structures and fluorescence properties have been discussed.

Five LnIII complexes based on indazole radical have been synthesized and characterized by X-ray crystal diffraction: [Ln(hfac)3(NITIn)(H2O)]·XCH2Cl2·YC7H16 (Ln = Pr(1), Sm(2), Gd(3), hfac = hexafluoroacetylacetone; NITIn = (3-(1′-oxyl-3′-oxido-4′,4′,5′,5′-tetramethyl-4,5-hydro-1H-imidazol-2-yl)indazole) and [Ln(hfac)3(NITIn)] (Ln = Tb(4), Dy(5)). Compounds 1–3 are isostructural and crystalize in P21/n space group, while compounds 4–5 crystalize in P21/c space group. In compounds 1–3, the coordination number around the lanthanide ion is nine, and the polyhedron is in distorted 4,4,4-tricapped trigonal prism (C4v) or muffin (Cs) environment finished by three bischelate hfac− ligands, one bidentate radical ligand and one water molecular. The coordination number around the lanthanide ion in 4–5 is eight, and the polyhedron is in distorted square antiprism (D4d) environment. DC magnetic studies show that Pr, Sm, Tb and Dy complexes are paramagnetic. In addition, Tb and Dy complexes exhibit slow frequency-dependence of ac magnetic susceptibilities, which indicates the presence of slow magnetic relaxation.

Three new lanthanide-nitronyl nitroxide radical complexes were successfully synthesized with the formula of [Ln(hfac) 3 (PyNONIT) 2 ] (Ln=Dy ( 1 ), Tm ( 2 ), Ho ( 3 )). All the complexes were isostructural and crystallized in C 2/ c space group, in which the central metal ions were eight-coordinated in slightly distorted square antiprism coordination geometries ( D 4d symmetry). Magnetic studies indicated the existence of antiferromagnetic interaction in complexes 1–3 .

Five lanthanide complexes [Ln(hfac)3(8-MeOTQ-2-NIT)] constructed by a tridentate chelating 8-methoxyquinoline substituted nitronyl nitroxide radical (Ln ​= ​Gd (1), Tb (2), Dy (3), Ho (4), Er (5), hfac ​= ​hexafluoroacetylacetonate, 8-MeOTQ-2-NIT ​= ​2-(8-methoxyquinoline)-4,4,5,5- tetra-methylimidazoline-1-oxyl-3-oxide) have been successfully synthesized and characterized. The five complexes have similar mononuclear two-spin structures with one LnIII ion and one radical (Rad) in the molecules. And all LnⅢ ions are nine-coordinated in the geometry between mono-capped square antiprism (C4v) and a trigonal bipyramidal (D3h). Alternating current magnetic studies show that Tb and Dy complexes display frequency dependence of out of phase signals indicating the slow magnetic relaxation behavior of single molecular magnets. The ferromagnetic interactions in Gd/Tb-Rad complexes and the very weak antiferromagnetic interactions in Dy/Ho/Er-Rad complexes were estimated by the rough model combining lanthanide single ions approximation and molecular-field approximation.

One coordination polymer {[Dy(BTTA)1.5(H2O)4.5]n (Dy-1) was successfully obtained via solvo-thermal reaction of Dy(NO3)3⋅6H2O and 2,5-bis-(1H-1,2,4-triazol-1-yl)terephthalic acid (H2BTTA). Single-crystal X-ray diffraction analysis shows that the complex exhibits two-dimensional lay-by-lay structure with one-dimensional channels along b direction, while DyIII ion exhibited as distorted spherical capped square antiprism (C4v) finished by nine oxygen atoms from three BTTA ligands and five water molecules. Magnetic studies show that both of the Orbach and Raman processes contribute to the magnetic relaxation behavior of Dy-1 under low temperature.

In order to explore diverse luminescence properties of Eu3+ in inorganic phosphors, a series of novel deep-red-emitting Ca2Ga2GeO7 phosphors were successfully synthesized by solid-state reactions. The phase formation was verified by the X-ray diffraction patterns and Rietveld refinement and there is only one kind of Ca2+ site in Ca2Ga2GeO7. The excitation spectrum shows typical excitation peaks of Eu3+ and the broad band ranging from 200 nm to 300 nm was composed of the charge transfer band of O2–-Eu3+ and Ga3+-O2– transition band. The emission spectrum depicts that the intensity of the peak located at 704 nm (5D0 → 7F4) is higher than that of 618 nm (5D0 → 7F2), which finally leads to the deep-red emission of the phosphor with high color saturation. The coordination dodecahedron of EuO8 distorted from a cubic geometry to the square antiprism is responsible for the unusual emission of Eu3+. The research of the concentration quenching behavior, lifetime and luminescence decay curves imply that the energy transfer between Eu3+ ions finally leads to the concentration quenching, and the interaction type is d-d interaction. The charge compensation, quantum efficiency and the thermal stability of Ca2Ga2GeO7:Eu3+ were also studied.

The coordination chain {[Dy(dbm)3bpy]·C7H8}n (1) having only 4,4′-bipyridine as connector has been prepared in high yield and its structural and magnetic properties have been investigated. It is isostructural with the terbium analogue {[Tb(dbm)3bpy]·C7H8}n (2) and features units repeating in a 1D-zigzag fashion, where the metal is octa-coordinated in a distorted square antiprism geometry. Despite the 1D structure, the absence of paramagnetic connectors prevents the direct magnetic intrachain interaction among the lanthanide ions. In zero magnetic field, only a small fraction of the magnetization of 1 displayed slow dynamics with no dependence on temperature. Upon application of a 1 kOe magnetic field, a relaxation process appears, compatible with a mixed Raman/Direct mechanisms. Magnetic dilution in the diamagnetic Y(III)-based analogue revealed that actually two distinct relaxation processes are active for 1, whose temperature dependence can be interpreted again with a mixed Raman/Direct relaxation model. Compound 2 displayed only in-field slow relaxation, compatible with the models employed for 1.

Two binuclear lanthanide complexes [Ln(3,4,-DEOBA)3DIPY]2 DIPY (Ln = Tb (1), Dy (2); 3,4,-DEOBA = 3,4-diethoxybenzoate; DIPY = 2,2′-bipyridine) have been synthesized and characterized. The single crystals of complexes 1 and 2 were obtained. And the two complexes are isostructural with a coordination number of eight to form a distorted square antiprism. Carboxylic groups adopt two modes coordinating with Ln(III) ions: bidentate chelate, and bridging bidentate. Binuclear complexes 1 and 2 are stitched together via π–π stacking interactions to form 1D chain and 2D layer supramolecular structures. The two complexes were characterized by elemental analysis, IR spectra, and powder X-ray diffraction. The luminescence spectra of complexes 1 and 2 show the characteristic emissions of Tb3+ (5D4 → 7F6-3) and Dy3+ (4F9/2 → 6H15/2, 6H13/2). The thermal decomposition mechanisms for title complexes were studied by the technology of TG-FTIR. And the heat capacities of two complexes were measured by DSC in the temperature range from 258.15 to 343.15 K. The smoothed heat capacities and thermodynamic functions for complexes 1 and 2 were calculated by fitted polynomial and thermodynamic equations.

The one-step metal-promoted condensation reaction of salicylaldehyde with diethylenetriamine in the presence of rare earth metal ions carried out in the same experimental conditions produces two types of salicylaldimine complexes. The compounds were characterized by spectroscopic data (ESI-MS, IR, UV/Vis, luminescence) and X-ray crystallography. The complexes contain the deprotonated tetradentate C11H16N3O = (L1)1− N-(salicylidene)-diethylenetriamine or pentadentate C18H19N3O2 = (L2)2− N,N′-bis(salicylidene)-diethylenetriamine ligand as a result of the [1+1] or [2+1] Schiff base condensation, respectively. The metal ions are bonded to all the potential nitrogen and oxygen donor atoms. The crystal structures of the complexes reveal two different supramolecular architectures: a monomer in [Tm(C11H16N3O)2]NO3·CH3OH complex with formation of a two-dimensional self-assembled network and a dimer in [M2(C18H19N3O2)2(NO3)2] complexes (M = Y3+, Eu3+or Lu3+), although in all cases the metal ions are eight-coordinated with distorted square antiprism geometry.

A series of mononuclear [Ln(L)(H2O)(NO3)(solv)]·solv, (Ln = Pr (1), Nd (2), Sm (3), Eu (4), Gd (5), Tb (6–6a), Dy (7); solv = DMF, DMSO, H2O) and L = 2,4-bis(2-hydroxybenzylidenehydrazino)-6-methoxy-s-triazine complexes were prepared. The lanthanide(III) ions are nine-coordinated in the complexes and are bound to the O atoms of bidentate nitrate, three N and two O atoms of a pentadentate L ligand and one O atom from water and one O atom from dimethylformamide with a spherical capped square antiprism coordination environment in 1–7. The compounds have been characterized by means of elemental analysis, IR spectroscopy, UV–Vis spectroscopy, X-ray diffraction, and thermal analysis. Lanthanide-centered emission of the complexes is overlapped by the ligand emission.

A 1:1 complex of Lanthanide-substituted Lindqvist-type oxo-nitrosyl polymolybdate [NBu4][La(CH3OH)2(DCU)NO3{Mo5O13(OMe)4(NO)}]·CH3OH (1) has been successfully synthesized by a one-pot self-assembly process of hydroxylamine hydrochloride with octamolybdate, DCC and La(NO3)3 in methanol under mild reaction conditions. The structure is determined by X-ray crystallography. It is notable that the compound is a Lindqvist-type POM with a capped lanthanum ion which is nine coordinated in a distorted square antiprism geometry. Interestingly, NO3− as the precursor, as well as the hydrated product DCU of DCC, are both coordinated with Lanthanum ion. The structure has also been characterized by IR, UV–vis and photoluminescence analysis. Photoluminescence analysis reveals that compound 1 emits weak green light in CH3CN, with the maximum emission at 530 nm.

Two eight-coordination containing square antiprism polyhedra, [Ln(Gly) 4 Im·(ClO 4 ) 4 ] n (Ln:Nd, Sm) were synthesized through the self-assembly of Ln 3+ (Ln:Nd, Sm) ions, glycine and imidazole in aqueous solution and characterized by X-ray single crystal diffraction. Both of the complexes crystallized in the C 2/ c space group. In the cluster, each Ln 3+ ions was eight-coordination by eight oxygen atoms of the glycine. The coordination sphere of each Ln 3+ ions could be described as a distorted square antiprism. Two central Ln 3+ ions were connected by four bridging carboxyl groups from four glycine molecules. The Ln–O bond distances were related to the coordination geometries of the ligands. The complexes had two special solid–solid phase transitions at 224 K and 248 K, which were interpreted as a freezing-in phenomenon of the reorientational motion of perchlorate ions ClO 4 − and the orientational order/disorder process of ClO 4 − ions. The decomposition mechanism of the complexes was deduced to be three stages from 300 to 700 K. The fluorescent excitation and emission spectra showed that the complexes had strong fluorescent property.

A series of luminescent anhydrous eight-coordinated anhydrous complexes of the general formula [Ln(tfaa)3phen] [Ln = La(1), Pr(2), Nd(3), Eu(4), Tb(5), Dy(6), Ho(7), Er(8), Tm(9), Yb(10) and Lu(11); tfaa = 1,1,1-trifluoro-2,4-pentanedione and phen = 1,10-phenanthroline] have been synthesized and fully characterized by elemental analysis, ESI–MS, thermogarvimetric analysis (TGA), FT-IR and 1H NMR spectroscopy. The complexes retain their identity in solution, phen and β-diketonate (methine and methyl) protons resonances are shifted in opposite directions and lanthanide induced shifts (LISs) is dipolar in nature. The unknown geometry of the complexes was determined from semi-empirical Sparkle/RM1 method. A distorted square antiprism geometry is proposed for [Eu(tfaa)3phen] which is further attested by NMR spectroscopy. The hypersensitive transitions of Nd(III), Ho(III) and Er(III) complexes are sensitive to the environment (solvent), which is reflected by the oscillator strength and band shape of the transitions. The room-temperature PL spectra of Pr(III), Eu(III), Tb(III), Dy(III) and Tm(III) complexes in solution produce their characteristic red, brilliant red, green, yellow and blue emissions, respectively. The replacement of water molecule from the inner-coordination sphere by phen ligand and forming highly protective coordination environment (LnO6N2) by the tfaa− and phen around the Ln(III) ion, leads to increase in the photoluminescence quantum yield (PLQy) and the luminescence lifetime. Theoretical Judd-ofelt and PL parameters of [Eu(tfaa)3phen] complex including PLQy predicted by the Sparkle/RM1 method are in excellent agreement with the experimental values, reflecting the efficacy of this method. The energy transfer processes show that energy transfer occurs via both T → 5D1 (6.98 × 106) and T→ 5D0 (7.39 × 106) levels. Furthermore, Eu and Tb complex display bright red and green luminescence and therefore interesting photonics applications could be foreseen.

The atomic structure of Fe 42 Co 20 Nb 8 B 30 glassy alloy was investigated using synchrotron high-energy X-ray diffraction (XRD), Mossbauer spectroscopy (MS) and Reverse Monte Carlo modeling (RMC). The RMC method basing on the results of XRD measurements was used for evaluating interatomic distances and coordination numbers in the local structure of quaternary alloy. The coordination numbers for Fe–Fe atomic pairs were additionally determined using Mossbauer spectroscopy investigations and Gonser et al. approach. The measured Mossbauer spectra of glassy alloy were decomposed into subspectra representing average Fe–Fe coordination numbers. A layer with thickness of 0.5 nm was extracted from the RMC configuration box containing 8000 atoms and short-range ordering in the investigated glassy alloy was analyzed within this fragment. Coordination polyhedra for Fe–Fe, Co–Fe, B–Fe and Nb–Fe atomic pairs are represented by the Bernal's tetrahedra and octahedral as well by the monocapped square antiprism with one atom missing and B-centered clusters related to the tricapped trigonal prisms. The presence of clusters with five-fold coordination for the Fe–Fe pairs is confirmed by analysis of the Mossbauer spectra using the Gonser approach.

Seven novel mixed-ligand complexes, [Ln(Hpma)2(phen)2(OAc)]·2H2O (Ln = La (1), Ce (2) and Nd (3)), [Er(Hpma)2(phen)(OAc)(H2O)]·EtOH·H2O (4), [Yb(Hpma)3(phen)]·2EtOH (5) and [Ln(Hpma)3(phen)(H2O)]·4H2O (Ln = Nd (6) and Gd (7)) (Hpma = N-(2,6-dimethylphenyl)oxamate; phen = 1,10-phenanthroline) were prepared in the presence of NaOH. Complexes 1–3 are isostructural and each metal ion is ten-coordinate, adopting a distorted sphenocorona geometry, with continuous shape measures of 2.702, 2.677 and 2.592, respectively. In contrast, the nona-coordinate complexes 4, 6 and 7 displayed spherical capped square antiprism molecular geometry, while the Yb(III) complex is bonded to three bidentate Hpma– ligands and one phen, forming a square antiprism structure (coordination number = 8). Besides the strong Ln(III)-ligand bonds as the main driving force for coordination, the relatively weak hydrogen bonds (O H∙∙∙O and N H∙∙∙O), C H∙∙∙O contacts, C H∙∙∙π, N H∙∙∙π and offset π-π interactions between the aromatic rings, play a key role in crystal packing. The UV–Vis-NIR absorption spectra of the metal complexes are associated with the π → π* transitions of phen and the Laporte-forbidden f-f transitions of the Nd(III), Er(III) and Gd(III) ions from the 4I9/2, 4I15/2 and 8S7/2 ground states, respectively, to the various excited J-levels. Cytotoxicity studies revealed antiproliferative activity in MCF-7 cells (p 0.05) for all the compounds, except for the positive control curcumin; indicating that the target compounds do not exert adverse effects on the immune system monocytes.

Bi(III) as its oxide combined with 2,4,6-pyridine tricarboxylic acid, H2pdc-COOH, and various pyridine-derived additives in dimethylformamide (dmf) under solvothermal conditions produced three novel bismuth coordination polymers, {[Bi(μ-pdc-COO)2][NH2Me2]3}n, 1, {[Bi(μ-pdc-COO)2][C5H7N2]3·C5H6N2}n, 2, and {[Bi2(μ-pdc-COO)2(μ-pdc-COOH)(pdc-COOH)][NH2Me2]4·2dmf·NHMe2}n, 3. The anionic coordination network topologies are two-dimensional, chains-of-loops and ladders, respectively, but the local 8-coordinate environments about the bismuth(III) centres are in each case between that of a square antiprism and that of a hexagonal bipyramid. When the 4-carboxy substituent in H2pdc-COOH is replaced by another potentially coordinating substituent to give 4-R-2,6-pyridine dicarboxylic acid, H2pdc-R (R = OH, NH2, Cl), the salts obtained contain discrete centrosymmetric dinuclear 8-coordinate bismuth anions with either double O-bridges between the metal centres, [Bi2(μ-pdc-R)2(pdc-R)2(dmf)2][NH2Me2]2 (R = OH, NH2), 4 and 5, or double carboxylate bridges with one long Bi–O bond, [Bi2(μ-pdc-NMe2)2(pdc-NMe2)2(dmf)2][NH2Me2]2, 6 (R = Cl, but replaced by dimethylamine during the reaction). The structures and supramolecular networks of 1–6 are described and compared as an exploration of alternatives to the conventional carboxylate-based organic linking units.

Centrosymmetric, acetato-bridged dinuclear coordination compounds with the formulae [La2(Hphen)2(OAc)4(H2O)2]·DMF·H2O (1), [Ln2(HNic)2(OAc)4(H2O)2]·DMF·H2O (Ln = La (2) and Nd (3)) and [Ln2(HNic)2(OAc)4(H2O)2]·DMF (Ln = Er (4) and Yb (5)) (H2phen = (E)-N'-(2-hydroxybenzylidene)benzohydrazide and H2Nic = (E)-N'-(2-hydroxybenzylidene)nicotinohydrazide) were isolated from the reactions of lanthanide acetates and hydrazones, and characterised by elemental analyses, IR spectroscopy, UV–Vis spectroscopy, X-ray diffraction studies and SHAPE 2.1. The nine-coordinate distorted spherical capped square antiprism complexes 1–3 crystallise in the triclinic space group P-1, while the eight-coordinate triangular dodecahedron (D2d) Er(III) and Yb(III) complexes belong to the monoclinic system (space group P21/c). Geometry optimisation of the monoanionic forms of the hydrazone ligands (Hphen– and HNic–) were performed at the DFT/B3LYP/aug-cc-pVTZ level of theory. Natural population analysis (NPA) and molecular electrostatic potential (MEP) maps indicated that the most preferred sites for electrophilic attack in the anionic ligands were the phenolate and carbonyl oxygen atoms, and the azomethine nitrogen atoms. Cytotoxic studies of the compounds on breast cancer (MCF-7), endometrial carcinoma (HEC-1A) and human monocytic (THP-1) cell lines using a 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl tetrazolium bromide (MTT) assay revealed that the hydrazone ligands and complexes 1–4 are partially cytotoxic against MCF-7 cells, while the Schiff bases and complexes 3–5 significantly inhibit cell growth in HEC-1A cells.

The clustering of trivalent lanthanide-doped fluorite was divided into four stages. Characters of the first three stage discrete clusters were studied by the density functional theory (DFT) based first principles calculation in the work. The results revealed the relative stabilities of first stage C4v and C3v were intimately correlated with that of the second and third stage clusters. The more stable C4v with interstitial Fi− at the nearest site would stabilize the second cubic sublattice centers and C3v with Fi− at next nearest site for the third square antiprism clusters. The lattice mismatch and projected density of states (pDOS) results indicated that coupling of electrostatic, strain, bonding and hybridization among Fi−, RE3+ and surrounded lattice anions controlled the site occupation and the correlations. The clusters and clustering features could be modulated and utilized to tune up- and down-conversion photoluminescence for designing of new lanthanide-doped fluorite materials.

Summary Long decoherence time is a key consideration for molecular magnets in the application of the quantum computation. Although previous studies have shown that the local symmetry of spin carriers plays a crucial part in the spin-lattice relaxation process, its role in the spin decoherence is still unclear. Herein, two nine-coordinated capped square antiprism neodymium moieties [Nd(CO3)4H2O]5– with slightly different local symmetries, C1 versus C4 (1 and 2), are reported, which feature in the easy-plane magnetic anisotropy as shown by the high-frequency electron paramagnetic resonance (HF-EPR) studies. Detailed analysis of the relaxation time suggests that the phonon bottleneck effect is essential to the magnetic relaxation in the crystalline samples of 1 and 2. The 240 GHz Pulsed EPR studies show that the higher symmetry results in longer decoherence times, which is supported by the first principle calculations., Graphical Abstract, Highlights • Neodymium-based complexes show the spin decoherence without the magnetic dilution • The higher structural symmetry results in longer spin decoherence times • The phonon bottleneck effect induces the slow magnetization relaxation behaviors, Materials Property; Molecules; Quantum Chemical Calculations

Two isostructural mononuclear rare-earth complexes, [(dbm)2Er(dtc)(phen)] (1-Er) and [(dbm)2Tb(dtc)(phen)] (2-Tb) (dbm− = dibenzoylmethanoate anion, dtc− = diethyldithiocarbamate anion, phen = 1, 10-phenanthroline) were synthesized and structurally characterized by single-crystal X-ray diffraction analyses. Each complex consists of one sulfur-donor ligand, two oxygen-donor ligands and one auxiliary ligand, and Er3+/Tb3+ ion locates in a distorted square antiprism. Magnetic measurements show that 1-Er displays slow magnetic relaxation behavior under an applied field, and solid-state emission spectra reveal that 1-Er exhibits characteristic emissions of Er3+ ion in the visible and near-infrared regions, indicating the dual functionality of 1-Er. Neither slow relaxation of the magnetization nor characteristic emissions of Tb3+ ion were observed for 2-Tb.

The macrocyclic ligand salt [H2LH2](ClO4)2, derived from the [2+2] condensation process involving 4-methyl-2,6-diformylphenol and 1,3-diaminopropane, has been used to synthesize the sandwich-type lanthanide(III) complexes [Ln(LH2)2](ClO4)3·2H2O (1–6, Ln = La–Eu, except Pm), [Ln(LH2)2](ClO4)3·CH3CN (7–13, Ln = Gd–Lu, except Er) and [Ln(LH2)(LH)](BPh4)2 (14–16, Ln = La, Nd and Sm). The X-ray crystal structures of the compounds 1, 7, 12, 13, 14 and 15 have been determined. In the isostructural [Ln(LH2)2](ClO4)3·CH3CN complexes of Gd (7), Yb (12) and Lu (13), the two macrocyclic ligands are considerably folded, albeit to different extents, and not symmetrically bound to the metal center. In these compounds, the metal center is coordinated with two imine nitrogen atoms and two phenolate oxygen atoms of each of the ligands (LH2), whose two other uncoordinated imine nitrogens are protonated and intramolecularly hydrogen-bonded with the phenolate oxygens. The structures determined for the La (14) and Nd (15) complexes of [Ln(LH2)(LH)](BPh4)2 are found to be identical. In these complexes, the ligand LH contains one N–H⋯O hydrogen-bonded unit, as against two in the ligand LH2. The [Ln(N2O2)2] coordination polyhedron in all the cases is a distorted square antiprism, although the extent of distortion in 7, 12 and 13 is less compared to that in 14 and 15. 1H NMR spectra of the [Ln(LH2)2]3+complexes in solution indicate a C2 symmetry. The 1H and 13C NMR signals of the EuIII complex 6 have been assigned on the basis of COSY, DEPT, HMQC and NOESY spectra. The photoluminescence spectra of the Sm(III) (5) and Eu(III) (6) complexes have been studied in a methanol–ethanol (1:4) glassy matrix at 77 K. The luminescence intensity of the hypersensitive 5D0 → 7F2 transition in 6 increases with the addition of triethylamine due to the formation of [Eu(LH2)(LH)]2+ and [Eu(LH)2]+ species, which in turn partially attenuate the quenching effect of the N–H⋯O oscillators on the emitting states of the metal ion.

The experimentally known dibismaborane Bi 2 B 10 H 10 is a potential precursor for the synthesis of metalladibismaboranes. In this connection the CoBi 2 B n frameworks of the lowest energy cobaltadibismaboranes CpCoBi 2 B n H n ( n = 7, 8, 9) have been investigated by density functional theory. In contrast to the corresponding cobaltadiphosphaboranes CpCoP 2 B n H n , as well as the related cobaltadicarbaboranes CpCoC 2 B n H n +2 , the lowest energy CpCoBi 2 B n H n structures have a CoBi 2 triangular face. Furthermore, structures with adjacent bismuth atoms in Bi–Bi edges are energetically preferred over isomeric structures with non-adjacent bismuth atoms. The ten lowest energy structures of the 10-vertex system CpCoBi 2 B 7 H 7 within 12 kcal/mol of the global minimum have a central CoBi 2 B 7 bicapped square antiprism. Nine of the ten lowest energy 11-vertex CpCoBi 2 B 8 H 8 structures within 9 kcal/mol of the global minimum have a central CoBi 2 B 8 most spherical deltahedron; eight of these structures have a bismuth atom at the unique degree 6 vertex. The tenth low-energy CpCoBi 2 B 8 H 8 structure has a central CoBi 2 B 8 polyhedron with a trapezoidal Bi 2 B 2 face. The only structures of the 12-vertex CpCoBi 2 B 9 H 9 within 65 kcal/mol of the global minimum are the nine possible structures with a central CoBi 2 B 9 icosahedron. The four such CpCoBi 2 B 9 H 9 structures with adjacent bismuth atoms all lie in energy below their isomers with non-adjacent bismuth atoms.

Two isostructural acylhydrazone based complexes, namely [Ce(penh) 2 (H 2 O) 4 ](NO 3 ) 3 ·4H 2 O ( 1 ) and [Sm(penh) 2 (NO 3 ) 2 ](NO 3 )·C 2 H 5 OH ( 2 ) (penh = 2-acetylpyridine nicotinohydrazone), have been obtained and characterized by physico-chemical and spectroscopic methods. The ten-coordinated lanthanide metal ion in each complex is surrounded by two independent tridentate neutral acylhydrazones with two ON 2 donor sets. The other four coordination oxygen atoms are from four water molecules and two bidentate nitrate anions for complexes 1 and 2 , respectively, thus giving distorted bicapped square antiprism geometry. Both complexes have excellent antitumor activity towards human pancreatic cancer (PATU8988), human colorectal cancer (lovo) and human gastric cancer(SGC7901) cell line. Furthermore, the cell apoptosis of complex 1 is detected by AnnexinV/PI flow cytometry.

The hydrothermal reactions of SrCl 2 with 4,5-dihydroxy-1,3-benzenedisulfonic acid disodium (Na 2 H 2 Tiron) and 1,10-phenanthroline ligands yielded two strontium complexes of general formula [Sr 2 (Tiron) 2 (phen) 2 (H 2 O) 3 ]·2H 2 phen·2H 2 O ( 1 ) and [Sr 3 (Tiron) 2 (phen) 3 (H 2 O) 5 ]·Hphen·0.5H 2 phen·8H 2 O ( 2 ) (phen = 1,10-phenanthroline). Complexes 1 – 2 were characterized by X-ray single crystal diffraction, elemental analyses, FT-IR, and thermogravimetric analyses. Complex 1 feathers a pentdentate Tiron-bridged dinuclear structure, where Sr1 and Sr2 ions exhibit bicapped trigonal prism and monocapped square antiprism geometries, respectively, interconnected through edge-sharing. Complex 2 is a pentdentate and hexadentate Tiron-bridged trinuclear one, where Sr1 and Sr2 ions all exhibit bicapped trigonal prism geometries, interlinked via edge-sharing, and Sr3 ion exhibits a rare triangular prism geometry. The luminescent properties were also studied, and the results exhibit that the luminescence emissions of complexes 1 – 2 happen the bathochromic shifts, compared with the ligands.

EuIII and TbIII complexes with a benzoate and a tripod N7 ligand, [LnIII(H3L)benzoate](ClO4)2·H2O·2MeOH (LnIII = EuIII and TbIII; H3L = tris[2-(((imidazol-4-yl)methylidene)amino)ethyl]amine), were synthesized and crystallized into an isomorphous structure. Each LnIII ion is coordinated by one tripod ligand and one benzoate, resulting in a nona-coordinated capped square antiprism geometry. The solid-state emission spectra displayed sharp bands of the f–f transitions. TbIII complex exhibits a magnetic anisotropy and the ac susceptibility measurements exhibited an out-of-phase signal under 1000 G bias field, indicative slow relaxation of magnetization.

Two thorium(Th) complexes with lactate or formate have been synthesized and characterized. Th(C3H5O3)4(H2O)2 (1) [C3H5O3H = lactic acid] has a mononuclear structure with ten-fold coordinated Th polyhedron in deformed bicapped square antiprism by four chelating lactate ligands via both carboxylate O and the alcohol O atoms in addition to two coordinated water molecules. The lactate ligands are enantiomer with equal proportion of R- and S-isomers. [Th6(O)4(OH)4(HCO2)12(H2O)6]·5H2O (2) [HCO2H = formic acid] is a hexanuclear Th nanocluster constructed by four oxo-, four hydroxyl, twelve μ2-bridging formate ligands and six water molecules. The calculated bond valence sums are in good agreement with the presence of equal numbers of oxo- and hydroxyl groups in the cluster. Thermal studies confirmed that both complexes lost water molecules first followed by the decomposition of the organic ligands to form ThO2 as the final product. The presence of bridging OH-groups in both complexes has been proven by Raman spectroscopy.

We report three-dimensional (3D) cyanido-bridged Mn–Nb and Co–Nb bimetal assemblies, Mn II 2 [Nb IV (CN) 8 ]·(L) 2 · n H 2 O ( 1 : L = 5-aminopyrimidine, n = 5; 2 : L = 5-methylpyrimidine, n = 4), and Co II 2 [Nb IV (CN) 8 ] (4-pyridinealdoxime) 8 ·2H 2 O ( 3 ). The single-crystal X-ray structural analyses show that 1 and 2 consist of isomorphic 3D cyanido-bridged network (monoclinic, P 2 1 / n ) composed of square antiprism Nb sites and distorted octahedral Mn sites. Both 1 and 2 show ferrimagnetism with Curie temperatures ( T C ) of 32 and 34 K, respectively, which is caused by the antiferromagnetic superexchange interaction between Mn II ( S = 5/2) and Nb IV ( S = 1/2) through the CN groups. 3 has a 3D cyanido-bridged network (tetragonal, I 4 1 / a ) composed of a dodecahedral Nb site and axially distorted pseudo-octahedral Co site. This compound shows ferromagnetic ordering with a T C of 18 K. Magnetization versus rotation angle of single crystal reveals that 3 has a large coercive field of 15 000 Oe as crystal is oriented to a -axis, which is due to the strong magnetic anisotropy on distorted Co II .

A new type of multifunctional single ionic chiral dysprosium complex (DyL) was obtained by the reaction of Dy(NO3)3 and salen-type Schiff base ligand N,N′-bis(3,5-dichlorosalicylidene)-(1R,2R)-1,2-cyclohexylenediamine. In the synthesis reaction, Dy(III) was found not only to be the central metal to coordinate with two Schiff base ligands, but also the Lewis acid catalyst to promote the partial decomposition of salen-type Schiff base ligand. Complex DyL crystallizes in a chiral and polar space group P21. The central metal Dy(III) adopts eight-coordinated square antiprism geometry with Δ absolute configuration. Complex DyL exhibits good SHG and ferroelectric properties. The single-crystal sample of DyL displays an obvious ferroelectric behavior with a remnant polarization (Pr) of ca. 4.51 μC cm−2 and Ec of ca. 28.11 kV cm−1. The solid luminescent spectrum of DyL presents characteristic emission 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 transitions of Dy(III).

The series of cobaltathiaboranes CpCoSBnHn (n = 6, 7, 8, 9, 10) related to the experimentally known CpCoSB8H8 and CpCoSB10H10 have been investigated by density functional theory. The lowest energy CpCoSBnHn (n = 6–10) structures are the closo deltahedra in accord with expectations for these 2n + 2 Wadean skeletal electron systems. In the lowest energy such structures the sulfur atom is located at a lowest degree vertex and the cobalt atom at a highest degree vertex. An alternative bicapped octahedral CpCoSB6H6 structure having the sulfur atom at a degree 3 capping vertex lies only ∼7 kcal/mol above the bisdisphenoid global minimum. For the 12-vertex CpCoSB10H10 system the three possible structures based on a B10CoS regular icosahedron lie more than 50 kcal/mol in energy below any non-icosahedral structures. The relative energy ordering of ortho < meta < para for these icosahedral CpCoSB10H10 structures is the opposite of the relative energy ordering of para < meta < ortho for the well-known icosahedral dicarbaboranes C2B10H10. One of the low-energy nine-vertex CpCoSB7H7 structures B7CoS-3 (Fig. 3) appears to be a frozen intermediate in the diamond-square-diamond process interconverting two isomeric tricapped trigonal prisms through a capped square antiprism intermediate.