SYNTHESES OF (C4H7OCH2C5H4)(2)LNCL (LN=ND, GD, DY, YB) AND CRYSTAL-STRUCTURE OF (C4H7OCH2C5H4)(2)DYCL

The reaction of lanthanide trichlorides with sodium tetrahydrofurfurylcyclopentadienyl in THF afforded bis(tetrahydrofurfurylcyclopentadienyl)lanthanide chloride complexes (C4H7OCH2C5H4),LnCl (Ln = Nd, Gd, Dy, Yb). All of the complexes were characterized

A NEW METHOD FOR THE SYNTHESIS OF LN(ETA-6-C6ME6)(ALCL4)3 (LN=ND, SM, GD, YB), AND THE X-RAY CRYSTAL-STRUCTURE OF YB(ETA-6-C6ME6)(ALCL4)3.MEC6H5

A series of neutral eta6-C6Me6 complexes of lanthanide elements Ln(176-C6Me6)(AlCl4)3 . MeC6H5(Ln = Nd, Sm, Gd, Yb) has been prepared directly in good yields from the reaction of LnCl3, AlCl3 and C6Me6 in toluene. The complexes have been characte

STUDIES ON ORGANOLANTHANIDE COMPLEXES .56. FORMATION OF ION-PAIR COMPLEXES [NA.3PHEN]+[LN(C5H5)3CL]-.PHEN (LN=LA, PR OR ND, PHEN = 1,10-PHENANTHROLINE) AND CRYSTAL-STRUCTURE FOR LN=PR

In the presence of 1,10-phenanthroline (phen), lanthanide chlorides LnCl3 reacted with cyclopentadienylsodium to give the novel complexes [Na.3phen]+[Ln(C5H5)3Cl]-.phen (Ln = La, Pr or Nd). In the praseodymium case, crystal structure analysis showed that

STUDIES ON ORGANOLANTHANIDE COMPLEXES .40. SYNTHESIS AND X-RAY STRUCTURE OF BIS (2-METHOXYETHYLCYCLOPENTADIENYL) YTTRIUM AND YTTERBIUM TETRAHYDROBORATES

New bis (2-methoxyethylcyclopentadienyl) yttrium and ytterbium tetrahydroborates (Ln = Y, 1; Yb, 2) have been synthesized in good yield by the reaction of bis (2-methoxyethylcyclopentadienyl) lanthanide chlorides (Ln = Y, Yb) with sodium borohydride in THF at room temperature. The title complexes were characterized by elemental analyses, MS, H-1 NMR and IR spectra. The crystal structures of 1 and 2 have been determined by X-ray diffraction. 1 crystallizes from THF-n-Hexane in space group Pna2(1) with unit cell parametert: a = 1.2390(3), b = 1.1339(2), c = 1.1919 (2) nm and V = 1.6745(6) nm3 with z = 4 for D(c) = 1.39 g.cm-3.The structure was solved by direct method and refined to final R = 0.061 (for 1730 observed reflections). The Space group of 2 is Pna2(1) with unit cell parameters: a = 1.2399(6), b = 1.1371(5), c = 1.1897(2) nm and V = 1.6773(1) nm3 with z = 4 for D(c) = 1.72 g.cm-3, R = 0.038 (for 2157 observed reflections). The X ray structures and IR reveal the bidentate yttrium and ytterbium tetrahydroborate complexes with the intramolecular coordination bonds between lanthanide metal and ligand oxygen atoms.

NMR-STUDIES ON THE COORDINATION OF RARE-EARTHS WITH GLYCYL-DL-VALINE AND THE CONFORMATION OF THEIR COMPLEX IN AQUEOUS-SOLUTION

In this paper lanthanide-induced shifts have been measured for C-13 and H-1 nuclei of glycyl-DL-valine in the presence of three lanthanide cations (La3+, Ho3+ and Yb3+) in aqueous solution. The stability constants of the coordination compounds of rare earths (Ho, Yb) with glycyl-DL-valine have been calculated. The coordination of rare earths with the ligand has been discussed. The simulation for conformation of lanthanide coordination compounds with glycyl-DL-valine shows that the ligand is coordinated to lanthanide ion through oxygen atoms of carboxyl group and the bond length of Ln-O is 0.226 nm. In the coordination compounds glycyl-DL-valine is in extended state with minimal steric hindrance.

PREPARATION AND MOLECULAR-STRUCTURE OF METHYLBIS(TERT-BUTYLCYCLOPENTADIENYL)NEODYMIUM AND METHYLBIS(TERT-BUTYLCYCLOPENTADIENYL)GADOLINIUM

Bis(t-butylcyclopentadienyl)lanthanide chloride (Ln = Nd or Gd) reacts with one equivalent of methyllithium in ether/tetrahydrofuran to give the complex [(C5H4tBu)2LnCH3]2 (Ln = Nd or Gd). The structure of [(C5H4tBu)2NdCH3]2 has been determined by X-ray analysis. The crystals are monoclinic of space group Cm with a = 9.538(2), b = 23.298(4), c = 9.505(3) angstrom, beta = 119.53(2)-degrees, V = 1828.0(7) angstrom 3, D(calc.) = 1.458 g/cm3 and Z = 2 for the dimer. The two (C5H4tBu)2Nd units in the dimer are connected by asymmetrical methyl bridges with independent Nd-C bond lengths of 2.70(2) and 2.53(2) angstrom and Nd-C-Nd angles of 94.7(9) and 87.3(6)-degrees.

SYNTHESIS AND STRUCTURE OF (ETA-5-C5H5)2YB.DME

(eta-5-C5H5)2YbCl.THF reacts with an equivalent molecular quantity of K(2,4-C7H11) (2,4-dimethyl pentadienyl potassium), and treatment of the product with DME yields (eta-5-C5H5)2Yb.DME. The crystal of (eta-5-C5H5)2Yb.DME belongs to the orthorhombic space group Fdd2 with a = 13.678(4) angstrom, b = 23.255(6) angstrom, c = 9.192(2) angstrom and Z = 8. The crystal parameters are found to differ from previously reported data.

SYNTHESES AND CRYSTAL-STRUCTURES OF TRIINDENYLLANTHANIDE COMPLEXES (ETA-5-C9H7)3LN.OC4H8 (LN=ND,GD,ER)

The complexes named in the title (eta-5-C9H7)3Ln.OC4H8 (Ln = Nd, Gd, Er) were synthesized by the reaction of anhydrous lanthanide trichlorides with indenyl potassium and cyclooctadienyl potassium (1:2:1 molar ratio) in THF. The complexes were characterized by elemental analysis, infrared and H-1-NMR spectroscopy, and mass spectrometry. In addition, the crystal structures of (eta-5-C9H7)3Nd.OC4H8 (1) and (eta-5-C9H7)3Gd.OC4H8 (2) were determined by an X-ray diffraction study. Complexes 1 and 2 belong to hexagonal space group P6(3) with unit cell parameters a = b = 11.843(3), c = 10.304(4) angstrom, V = 1251.7(9) angstrom-3, D(c) = 1.49 g.cm-3, Z = 2 for 1, and a = b = 11.805(2), c = 10.236(2) angstrom, V = 1235.4(6) angstrom-3 D(c) = 1.54 g.cm-3, Z = 2 for 2. The structures were solved by Patterson and Fourier techniques and refined by least-squares to final discrepancy indices of R = 0.049, R(w) = 0.053 using 925 independent reflections with I greater-than-or-equal-to 3-sigma(I) for 1, and R = 0.023, R(w) = 0.025 using 1327 independent reflections with I greater-than-or-equal-to 3-sigma(I) for 2. Coordination numbers for Nd3+ and Gd3+ are 10; the average bond lengths Nd-O and Gd-O are 2.557(21) and 2.459(13) angstrom, respectively. The structural studies showed the complexes to have 3-fold symmetry, but the THF molecule has no such symmetry; consequently the arrangement of carbon atoms in the THF molecule are disordered.

SYNTHESES OF BIS(TERT-BUTYLCYCLOPENTADIENYL)LANTHANOID CHLORIDE COMPLEXES AND CRYSTAL-STRUCTURES OF BIS(TERT-BUTYLCYCLOPENTADIENYL)CHLORO(BISTETRAHYDROFURAN)-PRASEODYMIUM AND BIS(TERT-BUTYLCYCLOPENTADIENYL)-CHLOROTETRAHYDROFURANYTTERBIUM

Reaction of lanthanoid trichloride with two equivalents of sodium t-butylcyclopentadienide in tetrahydrofuran affords bis(t-butylcyclopentadienyl)lanthanoid chloride complexes (t-BuCp)2LnCl. nTHF (Ln = Pr, Nd, n = 2; Ln = Gd, Yb, n = 1). The compound (t-BuCp)2PrCl.2THF (1) crystallizes from THF in monoclinic space group P2(1)/c with unit cell dimensions a = 15.080(3), b = 8.855(2), c = 21.196(5) angstrom, beta = 110.34(2)degrees, V = 2653.9 angstrom-3 and D(calcd) = 1.41 g/cm3 for Z = 4. The central metal Pr is coordinated to two t-BuCp ring centroids, one chlorine atom and two THF forming a distorted trigonal bipyramid. The crystal of (t-BuCp)2YbCl.THF (2) belongs to the monoclinic crystal system, space group P2(1)/n with a = 7.726(1), b = 12.554(2), c = 23.200(6) angstrom, beta = 97.77(2)degrees, V = 2229.56 angstrom-3, D(calcd) = 1.50 g/cm3 and Z = 4. The t-BuCp ring centroids, the chlorine atom and the oxygen atom of the THF describe a distorted tetrahedron around the central ion of ytterbium.

SYNTHESIS AND X-RAY CRYSTAL-STRUCTURE OF A MONOPENTAMETHYLCYCLOPENTADIENYL DERIVATIVE OF GADOLINIUM (NA(MU-2-THF)[(C5ME5)GD(THF)]2(MU-2-CL)3(MU-3-CL)2)2.6THF

The reaction of GdCl3 with 1 equiv of NaC5Me5 generates a neutral complex C5Me5GdCl2(THF)3 and a novel complex {Na(mu-2-THF)[(C5Me5)Gd(THF)]2(mu-2-Cl)3(mu-3-Cl)2}2.6THF whixh recrystallizes from THF in triclinic, the space group P1BAR with unit cell dimentions of a 12.183(4), b 13.638(6), c 17.883(7) angstrom, alpha-110.38(3), beta-94.04(3), gamma-99.44(3)-degrees, V 2721.20 angstrom-3 and D(calc) 1.43 g cm-3 for Z = 1. Least-squares refinement of 2170 observed reflections led to a final R value of 0.047. The title complex consists of two Na(mu-2-THF)[(C5Me5)Gd(THF)]2(mu-3-Cl)3(mu-3-Cl)2 units bridged together via two mu-2-THF to Na coordination. Each Gd ion is surrounded by one C5Me5 ligand, two mu-3-Cl, two mu-2-Cl and one THF in a distorted octahedral arrangement with average Gd-C(ring) 2.686(33), Gd-mu-2-Cl 2.724(7), Gd-mu-3-Cl 2.832(8) and Gd-O 2.407(11) angstrom. The sodium ion coordinates to two bridging THF, two mu-2-Cl and two mu-3-Cl to form a distorted octahedron with average Na-mu-2-O, Na-mu-2-Cl and Na-mu-3-Cl of 2.411(21), 2.807(15) and 2.845(12) angstrom, respectively.

Enrichment of lanthanides in aragonite

Using the constant addition technique, the coprecipitation of lanthanum, gadolinium, and lutetium with aragonite in seawater was experimentally investigated at 25 degrees C. Their concentrations in aragonite overgrowths were determined by inductive coupled plasma mass spectrometer. All these lanthanides were strongly enriched in aragonite overgrowths. The amount of lanthanum, gadolinium, and lutetium incorporated into aragonite accounted for 57%-99%, 50%-89%, and 40%-91% of their initial total amount, respectively. With the increase of aragonite precipitation rate, more lanthanides were incorporated into aragonite while their relative fraction in aragonite overgrowths decreased consistently. It indicated that the coprecipitation of lanthanides with aragonite was controlled by the kinetics of aragonite precipitation.

Identical extraction behavior and coordination of trivalent or hexavalent f-element cations using ionic liquid and molecular solvents

The extraction of both UO22+ and trivalent lanthanide and actinide ions (Am3+, Nd3+, Eu3+) by dialkylphosphoric or dialkylphosphinic acids from aqueous solutions into the ionic liquid, 1-decyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide has been studied and compared to extractions into dodecane. Radiotracer partitioning measurements show comparable patterns of distribution ratios for both the ionic liquid/aqueous and dodecane/aqueous systems, and the limiting slopes at low acidity indicate the partitioning of neutral complexes in both solvent systems. The metal ion coordination environment, elucidated from EXAFS and UV-visible spectroscopy measurements, is equivalent in the ionic liquid and dodecane solutions with coordination of the uranyl cation by two hydrogen-bonded extractant dimers, and of the trivalent cations by three extractant dimers. This is the first definitive report of a system where both the biphasic extraction equilibria and metal coordination environment are the same in an ionic liquid and a molecular organic solvent.

Imidazo[4,5-f]-1,10-phenanthrolines: Versatile ligands for the design of metallomesogens

2-Aryl-substituted imidazo[4,5-f]-1,10-phenanthrolines were used as building blocks for metal-containing liquid crystals (metallomesogens). Imidazo[4,5-f]-1,10-phenanthrolines are versatile ligands because they can form stable complexes with various d-block transition metals, including platinum(II) and rhenium(I), as well as with lanthanide(III) and uranyl ions and they can easily be structurally modified by a judicious choice of benzaldehyde precursor. None of the ligands designed for this study were liquid-crystalline. However, mesomorphism could be induced by their coordination to various metallic fragments. The thermal behavior of the metal complexes depended on the metal-to-ligand ratio and the substitution pattern of the coordinating ligands. Complexes with a metal-to-ligand ratio of 1:1 [ML, with M = Pt(II), Re(I)] were not liquid-crystal line. The lanthanide(III) complexes with a metal-to-ligand ratio of 1:2 [ML2 with M = Ln(III)] formed an enantiotropic cubic mesophase or were not liquid-crystalline, depending on the nature of the lanthanide(III) ion and the substitution pattern of the ligands. A 1:3 uranyl complex of the type [ML3](2+) exhibited a hexagonal columnar mesophase over a broad temperature range. Self-assembled monolayers of a europium(III) complex were investigated by scanning tunneling microscopy, which revealed that the complex formed well-ordered structures over long distances at the 1-octanoic acid-graphite interface. The rhenium(I) complexes and the europium(III) complexes with 2-thenoyl-trifluoroacetonate or dibenzoylmethanate and imidazo[4,5-f]-1,10-phenanthroline showed good luminescence properties.

Luminescence of LaF3:Ln(3+) Nanocrystal Dispersions in Ionic Liquids

Ionic liquids were used as solvents for dispersing luminescent lanthanide-doped LaF3:Ln(3+) nanocrystals (Ln(3+) = Eu3+ and Nd3+). To increase the solubility of the inorganic nanoparticles in the ionic liquids, the nanocrystals were prepared with different stabilizing ligands, i.e., citrate, N,N,N-trimethylglycine (betaine), and lauryldimethylglycine (lauryl betaine). LaF3:5%Ln(3+) :betaine could successfully be dispersed in 1-butyl-1-methylpyrrolidinium bis(tiifluoromethylsulfonyl)imide [C(4)mpyr][Tf2N], 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate [C(4)mpyr][TfO], and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [C(4)mim][Tf2N] but only in limited amounts. Red photoluminescence was observed for the europium(III)-containing nanoparticles and near-infrared luminescence for the neodymium(III)-containing systems.

Rare-earth complexes of ferrocene-containing ligands: Visible-light excitable luminescent materials

The ferrocene-derivatives bis(ferrocenyl-ethynyl)-1,10-phenanthroline (Fc(2)phen) and ferrocenoyltrifluoroacetone (Hfta) have been used to synthesize ferrocene-containing rare-earth beta-diketonate complexes. The complexes [Ln(tta)(3)(Fc(2)phen)] and [Ln(fta)(3)(phen)] (where Ln = La, Nd, Eu, Yb) show structural similarities to the tris(2-thenoyltrifluoroacetonate)(1,10-phenanthroline)lanthanide(III) complexes, [Ln(tta)(3)(phen)]. The coordination number of the lanthanide ion is 8, and the coordination sphere can be described as a distorted dodecahedron. However, the presence of the ferrocene moieties shifts the ligand absorption bands of the rare-earth complexes to longer wavelengths so that the complexes can be excited not only by ultraviolet radiation but also by visible light of wavelengths up to 420 nm. Red photoluminescence is observed for the europium(III) complexes and near-infrared photoluminescence for the neodymium(III) and ytterbium(III) complexes. The presence of the ferrocene groups makes the rare-earth complexes hydrophobic and well-soluble in apolar organic solvents.