Two series of novel rare earth complexes with dicyanamide [Ln(dca)2(phen)2(H2O)3][dca].(phen), (Ln = Pr, Gd, and Sm) and [Ln(dca)3(2,2'-bipy)2(H2O)]n, (Ln = Gd, Sm, and La): syntheses, crystal structures, and magnetic properties

Two series of novel complexes, [Ln(dca)(2)(Phen)(2)(H(2)O)(3)](dca).(phen) (Ln = Pr (1), Gd (2), and Sm (3), dca = N(CN)(-), phen = 1,10-phenanthroline) and [Ln(dca)(3)(2,2'-bipy)(2)(H(2)O)](n), (Ln = Gd (4), Sm (5), and La (6), 2,2'-bipy = 2,2'-bipydine), have been synthesized and structurally characterized by X-ray crystallography. The crystal structures of the first series (1-3) are isomorphous and consist of discrete [Ln(dca)(2)(Phen)(2)(H(2)O)(3)]+ cations, dca anions, and lattice phen molecules; whereas the structures of the second series (4-6) are characterized by infinite chains [Ln(dca)(3)(2,2'-bipy)(2)(H(2)O)](n). The Ln(III) atoms in all complexes are nine-coordinated and form a distorted tricapped trigonal prism environment. The three-dimensional frameworks of 1-6 are constructed by intermolecular hydrogen bond interactions. Variable-temperature magnetic susceptibility measurements for complexes 1, 2, 4, and 5 indicate a Curie-Weiss paramagnetic behavior over 5-300 K.     

Elevated-temperature metathesis syntheses of structurally novel alkali-metal tetrakis(3,5-di-tert-butylpyrazolato)lanthanoidate(III) complexes: toluene-coordinated discrete bimetallic complexes and supramolecular chains

Sodium and potassium tetrakis(3,5-di-tert-butylpyrazolato)lanthanoidate(III) complexes [M[Ln(tBu(2)pz)(4)]] have been prepared by reaction of anhydrous lanthanoid trihalides with alkali metal 3,5-di-tert-butylpyrazolates at 200-300 degrees C, and a 1,2,4,5-tetramethylbenzene flux for M=K. On extraction with toluene (or occasionally directly from the reaction tube) the following complexes were isolated: [Na(PhMe)[Ln(tBu(2)pz)(4)]] (1 Ln; 1 Ln=1 Tb, 1 Ho, 1 Er, 1 Yb), [K(PhMe)[Ln(tBu(2)pz)(4)]].2 PhMe (2 Ln; 2 Ln=2 La, 2 Sm, 2 Tb, 2 Ho, 2 Yb, 2 Lu), [Na[Ln(tBu(2)pz)(4)]](n) (3 Ln; 3 Ln=3 La, 3 Tb, 3 Ho, 3 Er, 3 Yb), [K[Ln(tBu(2)pz)(4)]](n) (4 Ln; 4 Ln=4 La, 4 Nd, 4 Sm, 4 Tb, 4 Ho, 4 Er, 4 Yb, 4 Lu), with the last two classes generally being obtained by loss of toluene from 1 Ln or 2 Ln, and [Na(tBu(2)pzH)[Ln(tBu(2)pz)(4)]].PhMe (5 Ln; 5 Ln=5 Nd, 5 Er, 5 Yb). Extraction with 1,2-dimethoxyethane (DME) after isolation of 2 Ho yielded [K(dme)[Ho(tBu(2)pz)(4)]] (6 Ho). X-ray crystal structures of 1 Ln (=1 Tb, 1 Ho; P2(1)/c), 2 Ln (=2 La, 2 Sm, 2 Tb, 2 Yb, 2 Lu; Pnma), 3,4 Ln (=3 La, 3 Er, 4 Sm; P2(1)/m), and 5 Ln (=5 Nd, 5 Er, and 5 Yb; P1) show each group to be isomorphous regardless of the size of the Ln(3+) ion. All complexes contain eight-coordinate [Ln(eta(2)-tBu(2)pz)(4)] units. These are further linked to the alkali metal by bridging through two (1,2,5 Ln) or three (3,4 Ln) tBu(2)pz groups which show striking coordination versatility. Sodium is coordinated by an eta(4)-PhMe, a micro-eta(2):eta(2)-tBu(2)pz, and a micro-eta(4)(Na):eta(2)(Ln)-tBu(2)pz ligand in 1 Ln, and by one eta(1)-tBu(2)pzH and two micro-eta(3)(Na):eta(2)(Ln) ligands in 5 Ln. By contrast, potassium has one eta(6)-PhMe and two micro-eta(5)(K):eta(2)(Ln) ligands in 2 Ln. Classes 3,4 Ln form polymeric chains with the alkali metal bonded by two micro-eta(3)(NNC-M):eta(2)(Ln)-tBu(2)pz ligands within [MLn(tBu(2)pz)(4)] units which are joined together by eta(1)(C)-tBu(2)pz-Na, K linkages.     

Ln(terpy)]3+ (Ln = Sm, Gd) entity forms isolated magnetic chains with [W(CN)8]3-

The reaction between Ln(NO3)3*xH2O, Cs3[W(V)(CN)8]*H2O and 2,2':6',2'-terpyridine (terpy) leads to the original isomorphous cyano-bridged [Ln(III)(terpy)(DMF)4][W(V)(CN)8] *6H2O [Ln = Gd (1), Sm (2)] 1-D chains. The crystal structures of {Ln(III)W(V)} chains and consist of alternating {[W(CN)8]} and {[Ln(terpy)]} building blocks. The neighbouring 1-D chains are weakly linked through pi-pi stacking interactions of the aromatic rings leading to 2-D supramolecular layers. The layers are linked through hydrogen bonds between H2O molecules and terminal cyano ligands. Magnetic studies revealed a weak antiferromagnetic coupling (J = -2.3(2) K) within the {Gd(III)W(V)} chains in . The positive effective coupling constant J = +2.0(5) K between the total angular momentum of the Sm(III) centre and the spin of the W(v) ion is equivalent to an antiferromagnetic character of the spin coupling between both centres in the {Sm(III)W(V)} chains of 2. The magnetic measurements suggest that they display an isolated magnetic chain behaviour.     

Assembling process of charged nonanuclear cationic lanthanide(III) clusters assisted by dichromium decacarbonyl hydride

The reaction of Ln(acac)(3).3H(2)O (Ln = Sm, Eu, Gd, Dy, Yb) with K[Cr(2)(CO)(10)(micro-H)] at different molar ratios and solvents leads to the formation of nonanuclear lanthanide hydroxo acetylacetonate complexes of general formula [Ln(9)(OH)(10)(acac)(16)][HCr(2)(CO)(10)]. The compounds are isomorphous, and the common cationic cluster core consists of a novel square antiprismatic arrangement of nine Ln atoms connected by micro(3), micro(4) hydroxo bridges and/or by acetylacetonate ligands as it results from the single-crystal X-ray analysis of the Sm derivative for which the most suitable crystals were obtained.     

Two new groups of homoleptic rare earth pyridylbenzimidazolates: (NC12H8(NH)2)[Ln(N3C12H8)4] with Ln = Y,Tb, Yb,and [Ln(N3C12H8)2(N3C12H9)2][Ln(N3C12H8)4](N3C12H9)2 with Ln = La,Sm, Eu

The compounds (NC(12)H(8)(NH)(2))[Ln(N(3)C(12)H(8))(4)], Ln = Y, Tb, Yb, and [Ln(N(3)C(12)H(8))(2)(N(3)C(12)H(9))(2)][Ln(N(3)C(12)H(8))(4)](N(3)C(12)H(9))(2), with Ln = La, Sm, Eu, were obtained by reactions of the group 3 metals yttrium and lanthanum as well as the lanthanides europium, samarium, terbium, and ytterbium with 2-(2-pyridyl)-benzimidazole. The reactions were carried out in melts of the amine without any solvent and led to two new groups of homoleptic rare earth pyridylbenzimidazolates. The trivalent rare earth atoms have an eightfold nitrogen coordination of four chelating pyridylbenzimidazolates giving an ionic structure with either pyridylbenzimidazolium or [Ln(N(3)C(12)H(8))(2)(N(3)C(12)H(9))(2)](+) counterions. With Y, Eu, Sm, and Yb, single crystals were obtained whereas the La- and Tb-containing compounds were identified by powder methods. The products were investigated by X-ray single crystal or powder diffraction and MIR and far-IR spectroscopy, and with DTA/TG regarding their thermal behavior. They are another good proof of the value of solid-state reaction methods for the formation of homoleptic pnicogenides of the lanthanides. Despite their difference in the chemical formula, both types (NC(12)H(8)(NH)(2))[Ln(N(3)C(12)H(8))(4)], Ln = Y (1), Tb (2), Yb (3), and [Ln(N(3)C(12)H(8))(2)(N(3)C(12)H(9))(2)][Ln(N(3)C(12)H(8))(4)](N(3)C(12)H(9))(2), Ln = La (4), Sm (5), Eu (6), crystallize isotypic in the tetragonal space group I4(1). Crystal data for (1): T = 170(2) K, a = 1684.9(1) pm, c = 3735.0(3) pm, V = 10603.5(14) x 10(6) pm(3), R1 for F(o) > 4sigma(F(o)) = 0.053, wR2 = 0.113. Crystal data for (3): T = 170(2) K, a = 1683.03(7) pm, c = 3724.3(2) pm, V = 10549.4(14) x 10(6) pm(3), R1 for F(o) > 4sigma(F(o)) = 0.047, wR2 = 0.129. Crystal data for (5): T = 103(2) K, a = 1690.1(2) pm, c = 3759.5(4) pm, V = 10739(2) x 10(6) pm(3), R1 for F(o) > 4sigma(F(o)) = 0.050, wR2 = 0.117. Crystal data for (6): T = 170(2) K, a = 1685.89(9) pm, c = 3760.0(3) pm, V = 10686.9(11) x 10(6) pm(3), R1 for F(o) > 4sigma(F(o)) = 0.060, wR2 = 0.144.     

A convenient route to lanthanide triiodide THF solvates. Crystal structures of LnI(3)(THF)(4) [Ln = Pr] and LnI(3)(THF)(3.5) [Ln = Nd, Gd, Y

The reaction between 1.5 equiv of elemental iodine and rare earth metals in powder form in THF at room temperature gives the rare earth triiodides LnI(3)(THF)(n)() in good yields. Purification by Soxhlet extraction of the crude solids with THF reliably gives the THF adducts LnI(3)(THF)(4) [Ln = La, Pr] and LnI(3)(THF)(3.5) [Ln = Nd, Sm, Gd, Dy, Er, Tm, Y] as microcrystalline solids. X-ray crystallography reveals that the early, larger lanthanide iodide PrI(3)(THF)(4) crystallizes as discrete molecules having a pentagonal bipyramidal structure, whereas the later, smaller lanthanide iodides LnI(3)(THF)(3.5) [Ln = Nd, Gd, Y] crystallize as solvent-separated ion pairs [LnI(2)(THF)(5)][LnI(4)(THF)(2)] in which the cations adopt a pentagonal bipyramidal geometry and the anions adopt an octahedral geometry in the solid state.     

Boundary Structures in a Series of Lanthanoid Hexacyanocobaltate(III) n-Hydrates and Their Raman Spectra

Studies on Ln[Co(CN)(6)].nH(2)O (Ln = lanthanoid ions; n = 5, 4) by means of thermal analysis, Raman spectroscopy, and X-ray crystallography were carried out, in order to establish the boundary structures in the series. From the thermal analyses, it was confirmed that the complexes include Ln'[Co(CN)(6)].5H(2)O (Ln' = La to Nd) or Ln"[Co(CN)(6)].4H(2)O (Ln = Sm to Lu). Raman spectra of the complexes suggested a different classification. The complexes having five H(2)O molecules displayed two single bands associated with nu(C-N) at around 2170 cm(-1). The complexes having four H(2)O molecules showed two distinct sets of bands of nu(C-N): one was a singlet, and the other was split. Nevertheless, the complex with Nd, which has five H(2)O molecules, exhibited single and split bands. This implies that the symmetry around Nd is lower than that of other complexes having five H(2)O molecules. According to the X-ray crystal analysis, the Pr complex is Pr[Co(CN)(6)].5H(2)O, hexagonal, P6(3)/m, with a = 7.473(1) ?, c = 14.212(1) ?, and Z = 2. On the other hand, the Nd complex is Nd[Co(CN)(6)].5H(2)O, orthorhombic, C222(1), with a = 7.458(4) ?, b = 12.918(3) ?, c = 14.172(2) ?, and Z = 4. Although the Nd complex has five H(2)O molecules, the crystals are orthorhombic and belong to the space group C222(1). Therefore, the structure of Nd[Co(CN)(6)].5H(2)O is regarded as the boundary structure: one of the coordinated water molecules is disordered, although the structure is essentially the same as that of Pr[Co(CN)(6)].5H(2)O. As Pr in Pr[Co(CN)(6)].5H(2)O changes into Nd, the symmetry around the metal atom is lowered and thus the bands associated with nu(CN) in Nd[Co(CN)(6)].5H(2)O and Sm[Co(CN)(6)].4H(2)O outnumber those of Pr[Co(CN)(6)].5H(2)O. The 5H(2)O complex with Nd loses one water molecule by thermal dissociation and changes into the more stable 4H(2)O complex, whose crystals are orthorhombic and belong to the space group Cmcm. Pr[Co(CN)(6)].5H(2)O also changes into the 4H(2)O complex, orthorhombic and Cmcm, when it dehydrates.     

Large cluster formation through multiple substitution with lanthanide cations (La, Ce, Nd, Sm, Eu, and Gd) of the polyoxoanion

Several new large polyoxotungstates have been synthesized by reaction of lanthanide cations with the well-known "As(4)W(40)" anion, [(B-alpha-AsO(3)W(9)O(30))(4)(WO(2))(4)](28-) (1). The heteropolyanions [(H(2)O)(11)Ln(III)(Ln(III)(2)OH)(B-alpha-AsO(3)W(9)O(30))(4)(WO(2))(4)](20)(-) (Ln = Ce, Nd, Sm, Gd) (2-4) (Ln(3)As(4)W(40)) and [M(m)()(H(2)O)(10)(Ln(III)(2)OH)(2)(B-alpha-AsO(3)W(9)O(30))(4)(WO(2))(4)]((18-m)(-)) (Ln = La, Ce, Gd and M = Ba, K, none) (5-7) (Ln(4)As(4)W(40)) have been isolated as alkali metal and ammonium salts, respectively, and characterized by single-crystal X-ray analysis, elemental analysis, and IR and (183)W-NMR spectroscopy. The X-ray analyses revealed interanionic W-O-Ln bonds between adjacent Ln(x)()As(4)W(40) units forming a "dimer" for x = 3 and chains for x = 4. Upon dissolving in water these bonds hydrolyze and the monomeric species form. The straightforward syntheses which require the use of concentrated NaCl solutions (1-4 M) and the addition of stoichiometric amounts of Ba(2+) or K(+) reemphasize the importance of the presence of appropriate countercations for the assembly of large polyoxometalate structures.     

Organometallic early lanthanide clusters: syntheses and X-ray structures of new monocyclopentadienyl complexes

The reaction of Ln(BH(4))(3)(THF)(3) or LnCl(3)(THF)(3) with 1 equiv of KCp*' ligand (Cp' = C(5)Me(4)n-Pr) afforded the new monocyclopentadienyl complexes Cp*'LnX(2)(THF)(n) (X = BH(4), Ln = Sm, n = 1, 1a, Ln = Nd, n = 2, 1b; X = Cl, Ln = Sm, n = 1, 3a) and [Cp*'LnX(2)](n') (X = BH(4), n' = 6, Ln = Sm, 2a, Ln = Nd, 2b; X = Cl, Ln = Nd, 4b). All these compounds were characterized by elemental analysis and (1)H NMR. Crystals of mixed borohydrido/chloro-bridged [Cp*'(6)Ln(6)(BH(4))(12-x))Cl(x)(THF)(n')] (x = 10, n' = 4, Ln = Sm, 2a', Ln = Nd, 2b'; x = 5, n = 2, Ln = Sm, 2a' ') were also isolated. Compounds 2a, 2b, 2a', 2b', and 2a' were structurally characterized; they all exhibit a hexameric structure in the solid state containing the [Cp*(3)Ln(3)X(5)(THF)] building block. The easy clustering of THF adducts first isolated is illustrative of the well-known bridging ability of the BH(4) group. Hexameric 2a was found to be unstable in the presence of THF vapors; this may be correlated to the opening of unsymmetrical borohydride bridges observed in the molecular structure.     

Magnetism of cyano-bridged hetero-one-dimensional Ln3+-M3+ complexes (Ln3+ = Sm,Gd, Yb; M3+ = FeLS,Co)

The reaction of Ln(NO(3))(3).aq with K(3)[Fe(CN)(6)] or K(3)[Co(CN)(6)] and 2,2'-bipyridine in water led to five one-dimensional complexes: trans-[M(CN)(4)(mu-CN)(2)Ln(H(2)O)(4) (bpy)](n)().XnH(2)O.1.5nbpy (M = Fe(3+) or Co(3+); Ln = Sm(3+), Gd(3+), or Yb(3+); X = 4 or 5). The structures for [Fe(3)(+)-Sm(3+)] (1), [Fe(3)(+)-Gd(3+)] (2), [Fe(3)(+)-Yb(3+)] (3), [Co(3)(+)-Gd(3+)] (4), and [Co(3)(+)-Yb(3+)] (5) have been solved; they crystallize in the triclinic space P1 and are isomorphous. The [Fe(3+)-Sm(3+)] complex is a ferrimagnet, its magnetic studies suggesting the onset of weak ferromagnetic 3-D ordering at 3.5 K. The [Fe(3+)-Gd(3+)] interaction is weakly antiferromagnetic. The isotropic nature of Gd(3+) allowed us to evaluate the exchange interaction (J = 0.77 cm(-)(1)).     

Distinct reaction pathways of peralkylated LnIIAlIII heterobimetallic complexes with substituted phenols

The protonolysis reaction of heterobimetallic peralkylated complexes [Ln(AlR4)2]n (Ln=Sm, Yb; R=Me, Et) with 2 equiv of HOC 6H 2 tBu 2-2,6-Me-4 affords the bis(trialkylaluminum) adducts Ln[(micro-OArtBu,Me)(micro-R)AlR2]2 in good yields. Analogous reactions with the less sterically demanding iPr-substituted phenol result in ligand redistributions and formation of X-ray structurally evidenced Ln[(micro-OAriPr,H) 2AlR2]2 (Ln=Yb, R=Me; Ln=Sm, R=Et), Yb[(micro-OAriPr,H)(micro-Et)AlEt2]2(THF), and [Et2Al(micro-OAriPr,H) 2Yb(micro-Et)2AlEt2]2. The solid-state structures of serendipitous alumoxane complex Sm[(micro-OArtBu,Me)AlEt2OAlEt2(micro-OArtBu,Me)](toluene) and dimeric AlMe 3-adduct complex [(AlMe3)(micro-OArtBu,Me)Sm(micro-OArtBu,Me) 2Sm(micro-OArtBu,Me)(AlMe3)] were also determined by X-ray crystallography. While the former can be discussed as a typical hydrolysis product of Sm[(micro-OArtBu,Me)(micro-Et)AlEt2]2, the latter was isolated from the 1:1 reaction of [Sm(AlEt4)2]n with HOArtBu,Me.     

Syntheses and characterizations of a series of novel Ln6Cu24 clusters with amino acids as ligands

With glycine or L-alanine as ligands, a series of novel 3d-4f heterometallic Ln(6)Cu(24) clusters with the formulas of [Sm(6)Cu(24)(mu(3)-OH)(30)(Gly)(12)(Ac)(12)(ClO(4))(H(2)O)(16)].(ClO(4))(9).(OH)(2).(H(2)O)(31) (1) and [Ln(6)Cu(24)(mu(3)-OH)(30)(Ala)(12)(Ac)(6)(ClO(4))(H(2)O)(12)].(ClO(4))(10).(OH)(7).(H(2)O)(34) (2.Ln) (Ln = Tb, Gd, Sm, and La) were synthesized by self-assembly, among which 1 and 2.Tb were characterized by X-ray structure analysis. The metal skeleton of the clusters may be described as a huge [Ln(6)Cu(12)] octahedron (constructed with 6 Ln(III) ions located at the vertices and 12 inner Cu(II) ions located at the midpoints of the edges) connected by 12 additional Cu(II) ions (every 2 are connected to 1 Ln(III) vertex). The temperature dependence of the magnetic susceptibilities of 2.Ln was investigated and was found to vary with the central rare-earth ions. Impedance spectroscopic measurements of 2.Ln reveal that they are ionic conductors.     

Lanthanide-ion-tuned magnetic properties in a series of three-dimensional cyano-bridged Ln(III)W(V) assemblies

The reaction of [W(CN)(8)](3-) with Ln(3+) and pyrazine in acetonitrile yielded a series of isostructural compounds formulated as Ln(H(2)O)(4)(pyrazine)(0.5)W(CN)(8) (Ln = La(1), Ce(2), Pr(3), Nd(4), Sm(5), Eu(6), Gd(7)). The Ln(iii) and W(v) centers in the structure are linked through cyanide groups to form two-dimensional (2D) layers, which are further pillared by pyrazine, generating 3D frameworks. The magnetic behavior for compounds 1-7 were driven by the lanthanide ions involved. The Ln(iii) and W(v) ions in compounds 2 and 5 are ferromagnetically coupled with magnetic ordering occurring at 2.8 K, comparable with magnetic ordering with the critical temperature of 1.9 K for compound 4. In addition, the antiferromagnetic interactions were observed in compounds 3 and 7, while no significant magnetic couplings were found in compounds 1 and 6.     

Solvothermal synthesis and characterization of a series of lanthanide thiostannates(IV): the first examples of inorganic-organic hybrid cationic lanthanide thiostannates(IV)

A series of new lanthanide thiostannates(IV), [Y(2)(dien)(4)(μ-OH)(2)]Sn(2)S(6) (1, dien = diethyl-enetriamine), (tetaH)(2)[Ln(2)(teta)(2)(tren)(2)(μ-Sn(2)S(6))]Sn(2)S(6) [Ln = Eu (2), Sm (3); teta = triethylenetetramine; tren = tris(2-aminoethyl)amine] and [Eu(2)(tepa)(2)(μ-OH)(2)(μ-Sn(2)S(6))](tepa)(0.5)·H(2)O (4, tepa = tetraethylene-pentamine) were solvothermally synthesized and structurally characterized. 1 consists of a binuclear [Y(2)(dien)(4)(μ(2)-OH)(2)](4+) cation and a discrete dimeric [Sn(2)S(6)](4-) anion. Both 2 and 3 are isostructural and composed of [Ln(2)(teta)(2)(tren)(2)(μ-Sn(2)S(6))](2+) cations, protonated triethylenetetramines (tetaH), and discrete dimeric [Sn(2)S(6)](4-) anions. A Sn(2)S(6)(4-) anion bridges two [Ln(teta)(tren)](3+) cations via the trans-S(t) (t = terminal) atoms to form the first examples of inorganic-organic hybrid thiostannate cations [Ln(2)(teta)(2)(tren)(2)(μ-Sn(2)S(6))](2+). 4 consists of one-dimensional (1-D) neutral chains [Eu(2)(tepa)(2)(μ-OH)(2)(μ-Sn(2)S(6))](n) built up from the linkage of dinuclear complex cations [Eu(2)(tepa)(2)(μ(2)-OH)(2)](4+) and bridging anions [Sn(2)S(6)](4-), free tepa molecules, and lattice water molecules. The present compounds exhibit wide-band gap semiconducting properties with absorption band edges between 2.40 and 2.91 eV.     

Manipulation of reaction pathways in redox transmetallation-ligand exchange syntheses of lanthanoid(II)/(III) aryloxide complexes

Redox transmetallation/ligand exchange reactions of lanthanoid metals (Ln), Hg(C6F5)2 and HOAr(OMe) (Ar(OMe) = C6H2-2,6-Bu(t)-4-OMe), in thf (tetrahydrofuran) gave, for Ln = Yb, [Yb(OAr(OMe))2(thf)3], and for Ln = Sm, a mixture of [Sm(II)(OAr(OMe))2(thf)3] and mainly [Sm(III)(Ar(OMe))3(thf)] x thf. X-Ray structure determinations show the divalent complexes to have distorted square-pyramidal stereochemistry with transoid thf and OAr(OMe) ligands in the basal plane. Treatment of [Yb(OAr(OMe))2(thf)3] with diethyl ether or PhMe at room temperature gave [Yb(OAr(OMe))2] or [Yb(OAr(OMe))2] x 0.5 PhMe. For lanthanoids Ln = Nd, Er or Y, the reactions with Hg(C6F5)2 and HOAr(OMe) yielded complex product mixtures, from one of which the novel erbium aryloxide fluoride cage [Er3(OAr(OMe))4(mu2-F)3(mu3-F)2(thf)4] x thf x 0.5 C6H14 was isolated. The cage core consists of a triangle of Er atoms joined to two mu3-fluoride ligands and three further mu2-fluorides bridge adjacent Er atoms. One of the Er atoms is six-coordinate with additionally two OAr(OMe) ligands whilst the other two have one OAr(OMe) and two thf ligands and are seven coordinate. Substitution of Hg(C6F5)2 by Hg(CCPh)2 in the redox transmetallation/ligand exchange reactions gave the new derivatives [Ln(OAr(OMe))3(thf)] x thf (Ln = La, Pr, Nd, Sm, Gd, Ho) in good yields whilst Ln = Yb gave [Yb(OAr(OMe))2(thf)3]. Recrystallisation of [Sm(OAr(OMe))3(thf)] x thf from dme (1,2-dimethoxyethane) yielded [Sm(OAr(OMe))3(dme)]. Structural characterisation of [Ln(OAr(OMe))3(thf)] x thf (Ln = Nd, Ho) and [Sm(OAr(OMe))3(dme)] showed monomeric four-coordinate distorted tetrahedral and five-coordinate distorted square-pyramidal complexes respectively. For the smaller lanthanoids Ln = Y, Er or Lu, reactions with Hg(CCPh)2 and HOAr(OMe) gave the mixed aryloxide/alkynide complexes [Ln(OAr(OMe))2(CCPh)(thf)2]. Oxidation of the divalent ytterbium aryloxide [Yb(OAr(OMe))2(thf)3] by Hg(CCPh)2 in thf gave the analogous [Yb(OAr(OMe))2(CCPh)(thf)2]. The erbium alkynide [Er(OAr(OMe))2(CCPh)(thf)2] x 0.25 C6H14 has distorted square-pyramidal stereochemistry with transoid OAr(OMe) and thf ligands in the basal plane and a rare (for Ln) terminal alkynide ligand in the apical position. The reactive Lu-C bond in the [Lu(OAr(OMe))2(CCPh)(thf)2] complexes could be slowly cleaved by free HOAr(OMe) in hydrocarbon solvents, yielding Lu(OAr(OMe))3 species and fortuitous partial hydrolysis of [Er(Ar(OMe))2(CCPh)(thf)2] gave the dimeric [Er(OAr(OMe))2(mu-OH)2]2.     

Synthesis of Arenethiolate Complexes of Divalent and Trivalent Lanthanides from Metallic Lanthanides and Diaryl Disulfides: Crystal Structures of [{Yb(hmpa)(3)}(2)(&mgr;-SPh)(3)][SPh] and Ln(SPh)(3)(hmpa)(3) (Ln = Sm, Yb; hmpa = Hexamethylphosphoric Triamide)

A convenient and one-pot synthetic method of lanthanide thiolate compounds was developed. An excess of metallic samarium, europium, and ytterbium directly reacted with diaryl disulfides in THF to give selectively Ln(II) thiolate complexes, [Ln(SAr)(&mgr;-SAr)(thf)(3)](2) (1, Ln = Sm; 2, Ln = Eu; Ar = 2,4,6-triisopropylphenyl), Yb(SAr)(2)(py)(4) (3, py = pyridine), and [{Ln(hmpa)(3)}(2)(&mgr;-SPh)(3)][SPh] (6, Ln = Sm; 7, Ln = Eu; 8, Ln = Yb; hmpa = hexamethylphosphoric triamide). Reaction of metallic lanthanides with 3 equiv of disulfides afforded Ln(III) thiolate complexes, Ln(SAr)(3)(py)(n)()(thf)(3)(-)(n)() (9a, Ln = Sm, n = 3; 9b, Ln = Sm, n = 2; 10, Ln = Yb, n = 3) and Ln(SPh)(3)(hmpa)(3) (11, Ln = Sm; 12, Ln = Eu; 13, Ln = Yb). Thus, Ln(II) and Ln(III) thiolate complexes were prepared from the same source by controlling the stoichiometry of the reactants. X-ray analysis of 8 revealed that 8 has the first ionic structure composed of triply bridged dinuclear cation and benezenethiolate anion [8, orthorhombic, space group P2(1)2(1)2(1) with a = 21.057(9), b = 25.963(7), c = 16.442(8) ?, V = 8988(5) ?(3), Z = 4, R = 0.040, R(w) = 0.039 for 5848 reflections with I > 3sigma(I) and 865 parameters]. The monomeric structures of 11 and 13 were revealed by X-ray crystallographic studies [11, triclinic, space group P&onemacr; with a = 14.719(3), b = 17.989(2), c = 11.344(2) ?, alpha = 97.91(1), beta = 110.30(2), gamma = 78.40(1) degrees, V = 2751.9(9) ?(3), Z = 2, R = 0.045, R(w) = 0.041 for 7111 reflections with I > 3sigma(I) and 536 parameters; 13, triclinic, space group P&onemacr; with a = 14.565(2), b = 17.961(2), c = 11.302(1) ?, alpha = 97.72(1), beta = 110.49(1), gamma = 78.37(1) degrees, V = 2706.0(7) ?(3), Z = 2, R = 0.031, R(w) = 0.035 for 9837 reflections with I > 3sigma(I) and 536 parameters]. A comparison with the reported mononuclear and dinuclear lanthanide thiolate complexes has been made to indicate that the Ln-S bonds weakened by the coordination of HMPA to lanthanide metals have ionic character.     

Cooperative processes governing formation of small pentanuclear lanthanide(III) nanoclusters and energy transport within and between them

Syntheses, lanthanide quantitative analyses, mass spectrometry and luminescence spectroscopy, and decay dynamics of crystals containing pentanuclear hetero-lanthanide(III) nanoclusters [(Ln'(5-x)Ln(x))(NO(3))(6)(mu(5)-OH)(mu(4)-L)(2)] (0 < or = x < or = 5), Ln' = Eu or Tb; Ln = La-Nd, Sm-Ho (hereafter Ln'(5-x) Ln(x)) were undertaken in search of information on factors governing self-assembly processes by which the clusters are formed and electronic interactions within and between them. The data obtained are consistent with the self-assembly of Ln'(5-x) Ln(x) nanoclusters being a concerted process featuring a profound expression of complementarity among mutually bridging [Ln(mu(4)-L](-) and [Ln(NO(3))(2)](+) components. The energy transport regime in crystals of Eu(5-x) Ln(x) is in the dynamic regime when x = 0 or Ln = La and, at 293 K, Ln = Dy, despite the presence of two crystallographically different Eu(3+) coordination environments which give rise to a doublet in the excitation and emission spectra of Eu(3+)((5)D(0)). The luminescence decay behavior of Eu(3+)((5)D(0)) in Eu(5-x) Ln(x) (Ln = Dy (for 77 K), Sm) is intermediate between the static and dynamic limits and reveals extensive electronic coupling among lanthanide ions, including many-body processes at relatively high Dy(3+) or Sm(3+) concentrations.     

Facile pyrazolylborate ligand degradation at lanthanide centers: X-ray crystal structures of pyrazolylborinate-bridged bimetallics

Adventitious hydrolysis of a number of different complexes with the molecular formula Ln(Tp(Me2))(2)X [Tp(Me2) = (HB(dmpz)(3)), where X is a basic anionic ligand] in various solvents, yielded crystals of highly insoluble dimers of the general formula [Ln(Tp(Me2))(mu-BOp(Me2))](2) (1) [Ln = La, Ce, Sm; BOp(Me2) = (HBO(dmpz)(2))(2)(-); dmpzH = 3,5-dimethylpyrazole]. The results of several single-crystal X-ray determinations are reported. One metal nitrogen distance, that lying across from the two negatively charged bridging oxygen atoms, is 0.06 A longer than the others, suggesting an unusual trans influence at a lanthanide center. The formation of 1 is proposed to involve the intermediacy of Ln(Tp(Me2))(2)OH formed by protonolysis with adventitious water.     

Structures and properties of porous coordination polymers based on lanthanide carboxylate building units

A series of 3-D lanthanide porous coordination polymers, [Ln(6)(BDC)(9)(DMF)(6)(H(2)O)(3)·3DMF](n) [Ln = La, 1; Ce, 2; Nd, 3], [Ln(2)(BDC)(3)(DMF)(2)(H(2)O)(2)](n) [Ln = Y, 4; Dy, 5; Eu, 6], [Ln(2)(ADB)(3)(DMSO)(4)·6DMSO·8H(2)O](n) [Ln = Ce, 7; Sm, 8; Eu, 9; Gd, 10], {[Ce(3)(ADB)(3)(HADB)(3)]·30DMSO·29H(2)O}(n) (11), and [Ce(2)(ADB)(3)(H(2)O)(3)](n) (12) (H(2)BDC = benzene-1,4-dicarboxylic acid and H(2)ADB = 4,4'-azodibenzoic acid), have been synthesized and characterized. In 1-3, the adjacent Ln(III) ions are intraconnected to form 1-D metal-carboxylate oxygen chain-shaped building units, [Ln(4)(CO(2))(12)](n), that constructed a 3-D framework with 4 × 7 ? rhombic channels. In 4-6, the dimeric Ln(III) ions are interlinked to yield scaffolds with 3-D interconnecting tunnels. Compounds 7-10 are all 3-D interpenetrating structures with the CaB6-type topology structure. Compound 11 is constructed by ADB spacers and trinulcear Ce nodes with a NaCl-type topology structure and a 1.9-nm open channel system. In 12, the adjacent Ce(III) ions are intraconnected to form 1-D metal-carboxylate oxygen chain-shaped building units, [Ln(4)(CO(2))(12)](n), and give rise to a 3-D framework. Moreover, 6 exhibits characteristic red luminescence properties of Eu(III) complexes. The magnetic susceptibilities, over a temperature range of 1.8-300 K, of 3, 6, and 7 have also been investigated; the results show paramagnetic properties.     

Heteroscorpionate rare-earth initiators for the controlled ring-opening polymerization of cyclic esters

A series of neutral rare-earth metal amides containing different achiral and chiral heteroscorpionate ligands was synthesized and characterized and these compounds were employed in the polymerization of cyclic esters. Thus, treatment of [Ln{N(SiHMe(2))(2)}(3)(thf)(2)] (Ln = Nd, Sm) with acetamide or thioacetamide heteroscorpionate ligands for 2 h at 0 °C afforded the α-agostic silylamido dimeric rare-earth compounds [Ln{N(SiHMe(2))(2)}(NNE)](2) (Ln = Nd and Sm; NNE = heteroscorpionate ligands, E = O, S) (1-8), some as enantiopure complexes. Complexes 1-8 contain dianionic heteroscorpionate pseudoallyl ligands resulting from C-H activation of the bridging methine group of the bis(pyrazol-1-yl)methane moiety and subsequent coordination to the metal center. However, when the reaction was carried out for 1 h at lower temperature new bis(silylamido) dimeric lanthanide compounds [Ln{N(SiHMe(2))(2)}(2)(NNE)](2) (Ln = Nd and Sm; E = O) (9 and 10) were obtained. The structures of the complexes were determined by spectroscopic methods and the X-ray crystal structures of 1, and 4 were also established. Neodymium complexes are active initiators for the ring-opening polymerization (ROP) of lactide (LA) and lactones, giving rise to medium-high molar mass polymers under mild conditions and with narrow polydispersities. These complexes were well suited for achieving well-controlled polymerization through an insertion-coordination mechanism. Achiral and racemic complexes did not affect stereocontrol in the polymerizarion of rac-LA but the enantiomerically pure complex 1 was found to exhibit a homosteric preference for one of the two enantiomers of rac-LA at low conversions.