SmIII Complexes Research Articles

Crystal structures of two SmIII complexes with dipicolinate [DPA]2- ligands: comparison of luminescent properties of products obtained at different pH values.

The formation of the two title compounds, Na3[Sm(DPA)3]·14H2O tris-odium tris-(pyridine-2,6-di-carboxyl-ato-κ3 O 2,N,O 6)samarate(III) tetra-deca-hydrate, Na3[Sm(C7H3NO4)3]·14H2O, and catena-poly[[[di-aqua-(6-carb-oxy-pyridine-2-carb-oxyl-ato-κ3 O 2,N,O 6)samarium(III)]-μ-pyridine-2,6-di-carboxyl-ato-κ4 O 2,N,O 6:O 2] tetra-hydrate], {[Sm(C7H3NO4)(C7H4NO4)(H2O)2]·4H2O}n, depends on the pH value adjusted with NaOH solution. In both crystal structures, the coordination spheres of the SmIII cations were found to be best described by a tricapped trigonal prism (TTP), with a more regular O6N3 donor set for Na3[Sm(DPA)3]·14H2O than that of O7N2 for [Sm(DPA)(HDPA)(H2O)2]·4H2O. The supra-molecular features of both crystal structures are dominated by O-H⋯O hydrogen bonds between water mol-ecules and the O atoms of the dipicolinato ligands. Samples were made from solutions at pH = 2, pH = 5, pH = 7, and pH = 10, and the crystals present in each sample were ground to a powder. The powder samples were analyzed with powder X-ray diffraction and luminescence spectroscopy. The splitting of the bands in the luminescence spectra recorded on powders at 77 K was observed to vary with the pH.

Interesting chemical and physical features of the products of the reactions between trivalent lanthanoids and a tetradentate Schiff base derived from cyclohexane-1,2-diamine.

The initial use of a tetradentate Schiff base (LH2) derived from the 2 : 1 condensation between 2-hydroxyacetophenone and cyclohexane-1,2-diamine in 4f-metal chemistry is described. The 1 : 2 reaction of Ln(NO3)3·xH2O (Ln = lanthanoid or yttrium) and LH2 in MeOH/CH2Cl2 has provided access to isostructural complexes [Ln(NO3)3(L'H2)(MeOH)] in moderate to good yields. Surprisingly, the products contain the corresponding Schiff base ligand L'H2 possessing six aliphatic -CH2- groups instead of the -CH-(CH2)4-CH- unit of the cyclohexane ring, i.e. an unusual ring-opening of the latter has occurred. A mechanism for this LnIII-assisted/promoted LH2 → L'H2 transformation has been proposed assuming transient LnII species and a second LH2 molecule as the H2 source for the reduction of the cyclohexane moiety. DFT calculations provide strong evidence for the great thermodynamic stability of the products in comparison with analogous complexes containing the original intact ligand. The structures of the PrIII, SmIII, GdIII, TbIII, and HoIII complexes have been determined by single-crystal X-ray crystallography. The 9-coordinate LnIII centre in the molecules is bound to six oxygen atoms from the three bidentate chelating nitrato groups, two oxygen atoms that belong to the bidentate chelating organic ligand, and one oxygen atom from the coordinated MeOH group. In the overall neutral bis(zwitterionic) L'H2 ligand, the acidic H atoms are clearly located on the imino nitrogen atoms and this results in the formation of an unusual 16-membered chelating ring. The coordination polyhedra defined by the nine donor atoms around the 4f-metal-ion centres can be best described as distorted, spherical capped square antiprisms. The EuIII, TbIII, and DyIII complexes exhibit LnIII-based luminescence in the visible region, with the coordinated L'H2 molecule acting as the antenna. Ac magnetometry experiments show that the DyIII member of the family behaves as an SIM at zero field and under external dc fields of 0.1 and 0.2 T without the enhancement of the peaks' maxima, suggesting that QTM is not the relaxation path. The GdIII complex behaves, rather unexpectedly, as a SIM with two different magnetic relaxation paths occurring at very close temperatures; this behaviour is tentatively attributed to a very small axial zero-field splitting (D ∼ 0.1 cm-1), which cannot be detected by magnetization or susceptibility experiments. The prospects of the present, first results in the lanthanoid(III)-LH2 chemistry are discussed.

Synthesis and reactivity of a β-diketiminate Sm

Attempts to stabilise a TmII metal centre with the bulky β-diketiminate ligand HC[C(Me)=N(DIPP)]2 (BDI) failed (DIPP, 2,6-diisopropylphenyl). Reaction of TmI2 and 2 equiv. (BDI)K gave the TmIII complex (BDI)(BDI-H)Tm (1) in which (BDI-H)2− is a doubly deprotonated ligand. However, following the same route, (BDI)2Sm (2) was isolated in 48% crystalline yield. Complex 2 is highly soluble in aromatic solvents or alkanes and was reacted with various reagents like phenazine, PhSSPh, O2, NO, cuminil and fluorenone. This led to isolation and structural characterisation of the following SmIII complexes: [(BDI)2Sm]2(μ-phenazine) (3), [(BDI)Sm(SPh)(μ-SPh)]2 (4), (BDI)(BDI-H)Sm (5a), (BDI)2Sm(OC13H8) (6) and (BDI)2Sm(NO2) (7). The rich redox reactivity of (BDI)2Sm (2) and its very high solubility in apolar solvents like hexane make it an attractive reducing agent in synthesis.

Two homochiral EuIII and SmIII enantiomeric pairs showing circularly polarized luminescence, photoluminescence and triboluminescence.

Two homochiral EuIII and SmIII tris(β-diketonate) enantiomeric pairs, based on fluorinated β-diketone (Hbtfa) and enantiopure asymmetric N,N'-donor ligands (LR and LS), Λ-Eu(btfa)3LR (R-1-Eu)/Δ-Eu(btfa)3LS (S-1-Eu) and Λ-Sm(btfa)3LR (R-2-Sm)/Δ-Sm(btfa)3LS (S-2-Sm) (btfa- = 4,4,4-trifluoro-1-phenyl-1,3-butanedionate and LR/LS = (-)/(+)-4,5-pineno-2,2'-bipyridine) were synthesized. The electronic circular dichroism (ECD) spectra confirmed their enantiomeric nature. R-1-Eu/S-1-Eu and R-2-Sm/S-2-Sm exhibit intense characteristic emissions of EuIII (red) and SmIII (orange-red) ions both in the solid state and in DCM with long lifetimes and high luminescence quantum yields. For example, the overall quantum yields reach up to 61% and 53% along with very high sensitization efficiency values of 82 and 79 for R-1-Eu in the solid state and in DCM, respectively. Notably, the corresponding values are determined to be 6.5% (solid state) and 3.1% (DCM) for R-2-Sm, which are among the highest quantum yields for rare SmIII tris(β-diketonate) luminescent complexes reported to date. Furthermore, R-1-Eu and R-2-Sm show a strong triboluminescence (TL) phenomenon visible with the naked eye in daylight. Moreover, R-1-Eu/S-1-Eu and R-2-Sm/S-2-Sm show circularly polarized luminescence (CPL) properties. Particularly, the luminescence dissymmetry factors (glum) for R-2-Sm/S-2-Sm are larger than those for R-1-Eu/S-1-Eu despite the fact that SmIII complexes usually show poorer emission than EuIII homologues, which is very rare in the reported EuIII and SmIII CPL-active complexes.

Dinuclear lanthanoid(III) dithiocarbamato complexes bridged by (E)-N-benzylidenepicolinohydrazonate: Syntheses, crystal structures and spectroscopic properties

(E)-N-Benzylidenepicolinohydrazide (Hbphz) was used to synthesize a series of hydrazonato-bridged homodinuclear LnIII2 dithiocarbamato (RR′dtc−) complexes of the form [{Ln(RR′ dtc)2}2(µ-bphz)2] {Ln = La, Pr, Nd, Sm or Eu; RR′ = dimethyl-(Me2) or pyrrolidine-(pyr)}. X-ray crystallographic studies revealed that these complexes possessed a common head-to-tail type dinuclear structural motif in which two hydrazonato ligands bridged two LnIII centers in the μ − 1 κ2N(py),O:2 κ2O,N(imine) mode and two RR′dtc ligands coordinated to each LnIII center. Interestingly, while the SmIII and EuIII complexes crystallized as simple 8:8-coordinate dinuclear molecules, the lighter LnIII (i.e. LaIII, PrIII and NdIII) complexes afforded in some cases 9:9-coordinate molecules, where the ninth coordination site was occupied by a solvent ethanol or methanol molecule. Even for the lighter LnIII complexes, the complexes were solved in dichloromethane or chloroform as the 8:8-coordinate dimer, as revealed by 1H NMR spectroscopy. In the UV–visible absorption and magnetic circular dichroism (MCD) spectra of the complexes, similar spectral patterns for ligand-centered and Laporte forbidden f–f transitions were observed. The MCD spectral studies demonstrated the characteristic magneto-optical behavior of the complexes.

A New Samarium(III) Complex of Liriodenine: Synthesis, Crystal Structure, Antitumor Activity, and DNA Binding Study

A novel SmIII complex [SmIII(LA)2(pic)3] (Hpic = picric acid), in which LA is a natural‐derived alkaloid, liriodenine, was synthesized and characterized by IR, elemental analysis, and single‐crystal X‐ray diffraction analysis. This complex showed enhanced solubility compared with liriodenine and its metal complexes that have been previously reported. The interaction of the SmIII complex with ct‐DNA was further investigated by various spectroscopic techniques, such as UV/Vis spectroscopy, fluorescence spectroscopy, circular dichroism spectroscopy (CD), and viscosity measurement. The results showed that the intrinsic binding constant Kb of the SmIII complex with ct‐DNA was calculated to be 5.03 × 103 L·mol–1 by UV/Vis absorption spectral analysis. The thermodynamic fluorescent spectral analysis suggested that the fluorescence intensity of the SmIII complex was weakened by ct‐DNA mainly through a dynamic quenching mechanism. The presence of Sm complex could increase the viscosity of DNA solution, so it was concluded that the complex bound with ct‐DNA via a moderate intercalative mode. Furthermore, this SmIII complex exhibited significant growth inhibition on the three typical tumor cell lines, HepG2, T‐24, and SK‐OV‐3, with the corresponding IC50 values, 10.76 ± 0.19, 8.85 ± 1.12, and 10.01 ± 0.55 μM, respectively. The in vitro antitumor activity was comparable with LA and cisplatin, which suggested that it might be a new broad spectrum antitumor agent with more satisfying solubility.

Molecular and Electronic Structure, and Hydrolytic Reactivity of a Samarium(II) Crown Ether Complex.

The reaction of SmI2 with dibenzo-30-crown-10 (DB30C10), followed by metathesis with [Bu4N][BPh4], allows for the isolation of [SmII(DB30C10)][BPh4]2 as bright-red crystals in good yield. Exposure of [Sm(DB30C10)]2+ to solvents containing trace water results in the conversion to the dinuclear SmIII complex, Sm2(DB30C10)(OH)2I4. Structural analysis of both complexes shows substantial rearrangement of the crown ether from a folded, Pac-Man form with SmII to a twisted conformation with SmIII. The optical properties of [SmII(DB30C10)][BPh4]2 exhibit a strong temperature dependence and change from broad-band absorption features indicative of domination by 5d states to fine features characteristic of 4f → 4f transitions at low temperatures. Examination of the electronic structure of these complexes via ab initio wave function calculations (SO-CASSCF) shows that the ground state of SmII in [SmII(DB30C10)]2+ is a 4f6 state with low-lying 4f55d1 states, where the latter states have been lowered in energy by ∼12 000 cm-1 with respect to the free ion. The decacoordination of the SmII cation by the crown ether is responsible for this alteration in the energies of the excited state and demonstrates the ability to tune the electronic structure of SmII.

Chiral luminescent lanthanide complexes possessing strong (samarium, SmIII) circularly polarised luminescence (CPL), and their self-assembly into Langmuir-Blodgett films.

The lanthanide directed self-assembly of chiral amphiphilic 2,6-pyridinedicarboxylic acid based ligands 1 and 2 with various Ln(CF3SO3)3 (Ln = TbIII, SmIII, LuIII, DyIII) salts was studied in CH3CN and evaluated with the expected 1 : 3 and 1 : 1 Ln : Ligand species forming in solution. Ligand chirality was retained and transferred, as depicted by circular dichroism (CD) and circularly polarised luminescence (CPL) measurements (for TbIII and SmIII), to the lanthanide centre upon complexation with high dissymmetry factor values for the SmIII complexes obtained (glum = -0.44 and 0.29 and 0.45 and -0.23 for the 4G5/2→6H5/2 and the 4G5/2→6H7/2 transitions of Sm·13 and Sm·23, respectively). The ability of the complexes to form stable Langmuir monolayers at the air-water interface was also established while Langmuir-Blodgett films of Tb·L3 and Sm·L3 exhibited lanthanide luminescent emission.

Syntheses, Structures, and Photoluminescence of Lanthanide Coordination Polymers Based on 4‐Oxo‐1,4‐dihydro‐2,6‐pyridinedicarboxylic acid

Investigating the coordination chemistry of H2CDA (4‐oxo‐1,4‐dihydro‐2,6‐pyridinedicarboxylic acid) with rare earth salts Ln(NO3)3 under hydrothermal conditions, structure transformation phenomenon was observed. The ligand, H2CDA charged to its position isomer, enol type structure, H3CAM (4‐hydroxypyridine‐2,6‐dicarboxylic acid). Six new lanthanide(III) coordination polymers with the formulas [Ln(CAM)(H2O)3]n [Ln = La (1), Pr, (2)] and {[Ln(CAM)(H2O)3]·H2O}n [Ln = Nd, (3), Sm, (4), Eu, (5), Y, (6)] were synthesized and characterized. The X‐ray structure analyses show two kinds of coordination structures. The complexes 1 and 2 and 3–6 are isostructural. Complexes 1 and 2 crystallize in the monoclinic C2/c space group, whereas 3–6 crystallize in the monoclinic system with space group P21/n. In the two kinds of structures, H3CAM displays two different coordination modes. The SmIII and EuIII complexes exhibit the corresponding characteristic luminescence in the visible region at an excitation of 376 nm.

Homochiral mono- and dinuclear SmIII complexes showing the effect of nuclearity on their photophysical properties

Using the enantiopure bis-bidentate ligands (−)/(+)-2,5-bis(4,5-pinene-2-pyridyl)pyrazine (LR/LS), two mono- and dinuclear SmIII enantiomeric pairs with the formulae [Sm(dbm)3LR/S]·C2H6CO·H2O (R-1 and S-1 being the isomers containing the LR and LS ligands, respectively, and dbm=dibenzoylmethanate) and [Sm2(dbm)6LR/S]·2H2O (R-2 and S-2 being the isomers containing the LR and LS ligands, respectively) have been synthesized and characterized by X-ray crystallography and spectroscopic technologies. The nuclearity of the complexes isolated depends on the ratio of the reactants. Circular dichroic (CD) spectra confirmed their chiroptical activities and enantiomeric natures. Measurement of the luminescence properties revealed that both the mono- and dinuclear SmIII complexes display the characteristic deep-red emissions of SmIII ions in the solid state. Notably, in contrast to the previously reported dinuclear SmIII complex based on a bis-β-diketonate ligand, whose emission intensity is much larger than that of the mononuclear analog, the intensity of the emission signal for the mononuclear complex R-1 is more than ten times larger than that of the dinuclear species R-2. The reason for this phenomenon is elucidated in this work. Thus, our research results demonstrate that the Sm nuclearity has a considerable effect on the photophysical properties of SmIII mono-β-diketonate complexes, which is contrary to the observation in SmIII bis-β-diketonate complexes.

Structure and luminescent properties of 2D Salen-type lanthanide coordination polymers from the flexible N,N′-bis(salicylidene)-1,4-butanediamine ligand

Three new Salen-type lanthanide coordination polymers, [Ln2(H2L)2(NO3)4(CH3O)2]n (Ln=Sm (1), Eu (2) and Lu (3); H2L=N,N′-bis(salicylidene)-1,4-butanediamine), have been synthesized by a solvothermal method and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectra and thermogravimetric analysis. Single-crystal X-ray diffraction studies reveal that complexes 1–3 are isostructural 2D coordination polymers based on dinuclear units, where the μ2-(methoxy-O)2-bridged Ln2O2 cores are linked by four Salen-type ligands in a bidentate mode. Each lanthanide ion is eight-coordinated by eight oxygen atoms, forming a distorted dodecahedral geometry. Luminescence analysis in the solid state at room temperature indicates that complex 1 exhibits the co-luminescence of the ligand and SmIII ions and complex 2 shows the characteristic red luminescence of EuIII ions. Furthermore, the energy transfer mechanisms are described and discussed.

3D Microporous Lanthanide–Organic Frameworks Constructed from Left‐ and Right‐Handed Helical Chains: Synthesis, Crystal Structure, and Tunable Photo­luminescence

AbstractNew lanthanide–organic frameworks, [Ln2(2,6‐NDS)3(IP)(H2O)4]·H2O {Ln = Sm (1), Eu (2), Tb (3); 2,6‐NDS = 2,6‐Anaphthalenedisulfonate, IP = 1H‐imidazo[4,5‐f][1,10]‐phenanthroline}, were synthesized and characterized. These complexes are isostructural and have three‐dimensional structures (3D) composed of a pair of entanglement double helixes. The structure is an open framework with rhombic channels filled with uncoordinated water molecules. The photoluminescence properties of the SmIII complex (1) and EuIII/TbIII‐doped complex were explored by adjusting the excitation wavelengths. Interestingly, SmIII complex 1 generated a white‐light emission, whereas the EuIII/TbIII‐doped complex (Tb0.95Eu0.05) allowed the realization of white‐light emission under broad UV wavelengths. An energy transfer for TbIII 5D4→EuIII 5D0 was observed.

Anionic lanthanide complexes with 3-methyl-1-phenyl-4-formylpyrazole-5-one and hydroxonium as counter ion

A series of [H3O]+[LnL4]−·nH2O complexes (n=1–3, Ln=Nd, (1), Sm (2), Eu (3), Tb (4); HL=3-methyl-1-phenyl-4-formylpyrazole-5-one) were synthesized and characterized. The structures of the SmIII and EuIII complexes were investigated by X-ray diffraction. The isostructutal crystalls 2 and 3 consist the tetrakis [LnL4]− anions which are linked by H-bonding with the hydroxonium counter-ion and water molecules. The lanthanide ion is situated in the center of distorted tetragonal antiprism formed by eight oxygen atoms of 4-formyl-5-hydroxypyrazolonate anions. The TbIII and SmIII complexes show strong luminescence in solid state, whereas the EuIII and NdIII complexes show low luminescence activity.

Homo- and Heterochiral Aggregations of Samarium(III) Complexes with Acetate and Tripod Ligand Containing Three Imidazole Groups

Abstract Three SmIII complexes with tripod heptadentate N7 ligands containing three imidazole groups, [Sm(H3L2-Me)(ac)](ClO4)2·2MeOH·H2O (1), [Sm(H3L2-Me)(ac)](ClO4)2·2EtOH (2), and [Sm(H3L4-Me)(ac)](ClO4)2·MeOH (3), were synthesized and the crystal structures were determined, where H3L2-Me and H3L4-Me are the 1:3 condensation products of tris(2-aminoethyl)amine and either 2-methyl-4-formylimidazole and 4-methyl-5-formylimidazole, respectively, and ac denotes acetate ion. Each SmIII ion is coordinated by a tripod heptadentate N7 ligand and two oxygen atoms of the acetate ion. Due to the screw coordination arrangement of the achiral tripod ligand to the SmIII ion, the complex-cation [SmIII(H3L2- or 4-Me)(ac)]2+ gives Δ- and Λ-enantiomorphs. In compounds 1 and 2, two adjacent [Sm(H3L2-Me)(ac)]2+ species with the same chirality are linked by an intermolecular imidazole···acetate hydrogen bond to form a homochiral 1D chain structure. Adjacent chains with the same chirality are stacked to give a conglomerate crystal in 1, while adjacent chains with opposite chiralities are stacked to give a racemic crystal in 2. In compound 3, two adjacent [Sm(H3L4-Me)(ac)]2+ species with the opposite chiralities are doubly bridged by two intermolecular imidazole···acetate hydrogen bonds to form a heterochiral dimer and the adjacent dimers are connected by ClO4− ion through the hydrogen bonds to form a racemic crystal.

Crystal Structures, Antioxidation, and DNA Binding Properties of SmIII Complexes

The dinuclear SmIII complexes with 1:1 metal to ligand stoichiometry were prepared from Sm(NO3)3·6H2O and three anionic tetradentate Schiff-base ligands derived from 8-hydroxyquinoline-2-carboxyaldehyde with benzoylhydrazine, 2-hydroxybenzoylhydrazine, and isonicotinylhydrazine, respectively. All the ligands and complexes can bind strongly to calf thymus DNA through intercalation with the binding constants at 105–106 M–1, but complexes present stronger affinities to DNA than ligands. All the ligands and complexes have strong abilities of antioxidation, but complexes and ligands containing an active phenolic hydroxy group show stronger scavenging effects on hydroxyl radical, and SmIII complex containing N-heteroaromatic substituent shows stronger scavenging effects for superoxide radical.

{6,6′-Dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilomethylidyne)]diphenolato-1κ4O1,O1′,O6,O6′:2κ4O1,N,N′,O1′}(ethanol-1κO)-μ-nitrato-1:2κ2O:O′-dinitrato-1κ4O,O′-samarium(III)zinc(II)

In the title heteronuclear ZnII–SmIII complex, [SmZn(C18H18N2O4)(NO3)3(CH3CH2OH)], with the hexa­dentate Schiff base compartmental ligand N,N′-bis­(3-methoxy­salicyl­idene)ethyl­enediamine (H2 L), the SmIII and ZnII ions are triply bridged by two phenolate O atoms from the Schiff base ligand and one nitrate anion. The five-coordinate ZnII ion is in a square-pyramidal geometry formed by the donor centers of two imine N atoms, two phenolate O atoms and one of the bridging nitrate O atoms. The SmIII center is in a ten-fold coordination of O atoms, involving the phenolate O atoms, two meth­oxy O atoms, one ethanol O atom, and two O atoms from two nitrate anions and one from the bridging nitrate anion. In the crystal, inter­molecular O—H⋯O and C—H⋯O inter­actions generate a layer structure extending parallel to (101).

{μ-6,6′-Diethoxy-2,2′-[ethane-1,2-diylbis(nitrilomethylidyne)]diphenolato}trinitratosamarium(III)nickel(II)

In the title heteronuclear NiII–SmIII complex (systematic name: {6,6′-dieth­oxy-2,2′-[ethane-1,2-diylbis(nitrilo­methyli­dyne)]diphenolato-1κ4O1,O1',O6,O6':2κ4O1,N,N′O1′}tri­nitrato-1κ6O,O′-samarium(III)nickel(II)), [NiSm(C20H22N2O4)(NO3)3], with the hexa­dentate Schiff base compartmental ligand N,N′-bis­(3-ethoxy­salicyl­idene)ethyl­enediamine (H2L) the Ni and Sm atoms are doubly bridged by two phenolate O atoms provided by the Schiff base ligand. The coordination of Ni is square planar with the donor centres of two imine N atoms and two phenolate O atoms. The samarium(III) centre has a deca­coordination environment of O atoms, involving the phenolate O atoms, two eth­oxy O atoms and two O atoms each from the three nitrates. Some weak C—H⋯O and O⋯Ni [3.381 (4) Å] inter­actions generate a two-dimensional zigzag sheet.

Reduction of Carbodiimides by Samarium(II) Bis(trimethylsilyl)amidesFormation of Oxalamidinates and Amidinates through C−C Coupling or C−H Activation

The reaction of [Sm{N(SiMe3)2}2(THF)2] (THF=tetrahydrofuran) with carbodiimides RN=C=NR (R=Cy, C6H3-2,6-iPr2) led to the formation of dinuclear SmIII complexes via differing C-C coupling processes. For R=Cy, the product [{(Me3Si)2N}2Sm(micro-C2N4Cy4)Sm{N(SiMe3)2}2] (1) has an oxalamidinate [C2N4Cy4]2- ligand resulting from coupling at the central C atoms of two CyNCNCy moieties. In contrast, for R=C6H3-2,6-iPr2, H transfer and an unusual coupling of two iPr methine C atoms resulted in a linked formamidinate complex, [{(Me3Si)2N}2Sm{micro-(RNC(H)N(Ar-Ar)NC(H)NR)}Sm{N(SiMe3)2}2] (2) (Ar-Ar=C6H3-2-iPr-6-C(CH3)2C(CH3)2-6'-C6H3-2'-iPr). Analogous reactions of RN=C=NR (R=Cy, C6H3-2,6-iPr2) with the SmII "ate" complex [Sm{N(SiMe2)3Na] gave 1 for R=Cy, but a novel C-substituted amidinate complex, [(THF)Na{N(R)C(NR)CH2Si(Me2)N(SiMe3)}Sm{N(SiMe3)2}2] (3), for R=C6H3-2,6-iPr2, via gamma C-H activation of a N(SiMe3)2 ligand.

{6,6′-Dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilomethylidyne)]diphenolato-1κ4O1,O1′,O6,O6′:2κ4O1,N,N′,O1′}(methanol-1κO)-μ-nitrato-1:2κ2O:O′-dinitrato-1κ4O,O′-cerium(III)zinc(II)

In the title heteronuclear ZnII–SmIII complex, [SmZn(C18H18N2O4)(NO3)3(CH3CH2OH)], with the hexa­dentate Schiff base compartmental ligand N,N′-bis­(3-methoxy­salicyl­idene)ethyl­enediamine (H2L), the SmIII and ZnII ions are triply bridged by two phenolate O atoms from the Schiff base ligand and one nitrate anion. The five-coordinate ZnII ion is in a square-pyramidal geometry formed by the donor centers of two imine N atoms, two phenolate O atoms and one of the bridging nitrate O atoms. The SmIII center is in a ten-fold coordination of O atoms, involving the phenolate O atoms, two meth­oxy O atoms, one ethanol O atom, and two O atoms from two nitrate anions and one from the bridging nitrate anion. In the crystal, inter­molecular O—H⋯O and C—H⋯O inter­actions generate a layer structure extending parallel to (101).

{6,6′-Diethoxy-2,2′-[ethane-1,2-diylbis(nitrilomethylidyne)]diphenolato}trinitratosamarium(III)copper(II)

A heteronuclear CuII–SmIII complex (systematic name: {6,6′-di­eth­oxy-2,2′-[ethane-1,2-diylbis(nitrilo­methyl­idyne)]­diphenol­ato-1κ4O1,O1′,O6,O6′:2κ4O1,N,N′,O1′}trinitrato-1κ6O,O′- samarium(III)copper(II)), [CuSm(C20H22N2O4)(NO3)3], with the hexa­dentate Schiff base compartmental ligand N,N′-bis­(3-ethoxy­salicyl­idene)ethyl­ene-1,2-diamine, has been synthesized and structurally characterized. The Cu and Sm atoms are doubly bridged by two phenolate O atoms provided by the Schiff base ligand. The coordination of the Cu atom is square planar, formed by two imine N and two phenolate O atoms. The SmIII atom has a decacoordination environment, formed by the phenolate O atoms, two ethoxy O atoms and two O atoms each from the three nitrates. No classical inter­molecular hydrogen bonds are found. Some weak C—H⋯O and O⋯Cu inter­actions [O⋯Cu = 3.167 (4) Å] generate a two-dimensional zigzag sheet.