Lanthanide Chloride Complexes Research Articles

Something You Need Might Be under Your Feet: Molecular Magnetism of Heavy Kramers Lanthanide Hydrated Chlorides and Their Complexes with Polydentate Terpy Ligand

A study of the molecular magnetism of the hydrated salts [Ln(H2O)6Cl2]Cl (Ln = Gd (1Gd), Dy (1Dy), Er (1Er), Yb (1Yb)) and lanthanide chloride complexes with 2,2′;6′,2″-terpyridine (terpy) synthesized on their basis, [Ln(H2O)4(terpy)Cl]Cl2·3H2O (Ln = Gd (2Gd), Dy (2Dy), Er (2Er), and Yb (2Yb), was carried out. It was found that both the initial hydrated chlorides containing Dy, Er, Yb, and their derivatives with terpyridine exhibit the properties of single-molecule magnets. For the complexes with terpyridine, the values of the remagnetization barriers increase from Er to Dy, while for the aquachlorides, the corresponding values increase in the series Ueff (1Dy) < Ueff (1Er). It was found that magnetic relaxation in Yb complexes mostly proceeds according to the Raman mechanism.

Complexes of lanthanide chlorides with tricyclohexylphosphine oxide. The single crystal X-ray structures and solution properties of pentagonal bipyramidal complexes [Ln(H2O)5(Cy3PO)2]3+·Cy3PO·3Cl− Ln = Dy, Er

The products of the reactions of tricyclohexylphosphine oxide, Cy3PO=L, with lanthanide chlorides (Ln=La, Dy, Er, Yb) have been investigated by solution NMR spectroscopy and single crystal X-ray crystallography (Dy, Er). The structures of the complexes are based on a pentagonal bipyramidal arrangement around the central Ln3+ ion with two Cy3PO in axial positions and five water molecules in the equatorial plane with molecular formulae LnLn(H2O)5·L·3Cl·H2O·EtOH. An extensive H-bonding network links the remaining Cy3PO and the chloride ions to the coordinated water molecules to form a polymeric unit. The variable temperature solution 31P NMR spectra in CD2Cl2 and CDCl3 indicate that the solid state and solution structures are similar and that exchange between H-bonded and lanthanide bonded Cy3PO occurs. This exchange is rapid for La but slower for the Er and Yb complexes. Differences in the spectra between the two solvents are discussed in terms of the polarity of the C–D bonds.

Synthesis and spectral study of yttrium and lanthanide chloride complexes of 2,3-dimethyl-4-formyl(benzhydrazide)-1-phenyl-3-pyrazolin-5-one

Synthesis and spectral study of yttrium and lanthanide chloride complexes of 2,3-dimethyl-4-formyl(benzhydrazide)-1-phenyl-3-pyrazolin-5-one

Syntheses and Crystal Structures of Mononuclear and Binuclear Lanthanide Halide Complexes with Diglyme

AbstractTwo types of isostructural complexes of lanthanide chlorides with diglyme have been synthesized. These are mononuclear molecular complexes [LnCl3(diglyme)(THF)] (Ln = Eu (1), Gd (2), Dy (3), Er (4), Yb (5); diglyme = diethylen glycol dimethyl ether) and binuclear molecular complexes [LnCl3(diglyme)]2 (Ln = Dy (3d), Er (4d), Yb (5d)). Complex 1 was obtained by the reaction of [EuCl3(DME)2] with diglyme in THF. The complexes 2–5 and 3d–5d resulted from reactions of LnCl3·6H2O, (CH3)3SiCl and diglyme in THF. The mononuclear complexes 2–5 crystallized directly from the solutions where the reactions of lanthanide compounds with diglyme took place. Recrystallizations of the powder products of the same reactions from dichloromethane resulted in the binuclear complexes 3d–5d. Reactions of lanthanide bromide hydrates, (CH3)3SiBr and diglyme in THF achieved mononuclear molecular complexes [LnBr3(diglyme)(L)] (Ln = Gd, L = H2O (6); Ln = Ho, L = THF (7)). Crystals of 6 and 7 were grown by recrystallization from dichloromethane. The lanthanide atoms (Ln = Eu–Yb) are seven‐coordinated in a distorted pentagonal bipyramidal fashion in all reported complexes, 1–7 and 3d–5d. Four oxygen atoms and three halide ions are coordinated to lanthanide atoms in 1–7, [LnX3(diglyme)(L)]. Four chloride ions, two bridging and two nonbridging, and three oxygen atoms are coordinated to lanthanide atoms in 3d–5d, [LnCl3(diglyme)]2.

Lanthanide chloride complexes of amine-bis(phenolate) ligands and their reactivity in the ring-opening polymerization of ε-caprolactone

Reaction of two equivalents of n-BuLi with sterically demanding amine-bis(phenol) compounds, H(2)O(2)NN'(R) (Me(2)NCH(2)CH(2)N{CH(2)-3,5-R(2)-C(6)H(2)OH}(2); R = t-Bu or t-Pe (tert-pentyl)) yields isolable lithium complexes, Li(2)(O(2)NN'(R)), in good yields. Upon reaction with one equivalent of LnCl(3)(THF)(x), the lithium salts afford rare earth amine-phenolate chloride complexes in good yields, Ln(O(2)NN'(R))Cl(THF); Ln = Y, Yb, Ho, Gd, Sm, Pr. Crystals of Y(O(2)NN'(t-Bu))Cl(THF), 1, and Sm(O(2)NN'(t-Bu))Cl(DME), 2, suitable for single crystal X-ray crystallographic analysis were obtained. In contrast to previously reported [{Gd(O(2)NN'(t-Pe))(THF)(micro-Cl)}(2)] and related La and Sm complexes, these species are monomeric. 1 contains Y in a distorted octahedral environment bonded to two amine, two phenolate, one THF and one chloride donor. 2 contains Sm in a distorted capped trigonal prismatic environment bonded to two amine, two phenolate, two DME oxygens and one chloride donor. The Ln(O(2)NN'(t-Pe))Cl(THF) complexes were active initators for the controlled ring-opening polymerization of epsilon-caprolactone with a tendency to form low molecular weight cyclic polyesters (M(n) 3000-5000). The conversion rates, although slower than related amido and alkyl species, were different for monomeric and dimeric initiators. The size of the metal centre also affected the conversions and the molecular weights achieved.

Peculiarities of the structure of lanthanide chloride complexes with heterocyclic diimines and the efficiency of energy transfer processes

Two families of lanthanide chlorides LnCl3L2(H2O)n and LnCl3L(H2O)m where L is 1,10-phenanthroline or 2,2′-bipyridine were synthesized. Their luminescence properties were investigated in the solid state and 1-dodecyl-3-methylimidazolium chloride solution. The structural peculiarities of lanthanide chlorides were elucidated by joint analysis of the X-ray, vibrational and luminescence data including the lifetime measurements. As a result the analysis of efficiency of energy transfer processes was performed and the correlation between the structure and the luminescence intensity was demonstrated in the systems studied.

Lanthanide Pybox Complexes as Catalysts for Enantioselective Silylcyanation of Aldehydes

Complexes of lanthanide chlorides with pybox ligands catalyze the enantioselective silylcyanation of aromatic and aliphatic aldehydes with ee's of up to 91% under mild and convenient conditions. Studies of catalysts prepared with pybox ligands of varying enantiomeric purity show no marked nonlinear effects, indicating a monometallic transition state. A mechanism for the catalytic reaction is proposed. Crystal structures of [LnCl2(S-Pri-pybox)2][LnCl4(S-Pri-pybox)] (Ln = Eu, Yb) are reported. The structure of the related triflate complex [La(OTf)3(S-Pri-pybox)2] is also reported. Diastereoselectivity has been observed in the reactions of Ln(OTf)3 with racemic Pri-pybox: for Ln = Eu, a heterochiral product containing one R- and one S-pybox ligand is observed, whereas for Ln = Yb a racemic mixture of homochiral bis(pybox) complexes is formed.

Synthesis, properties and solution speciation of lanthanide chloride complexes of triphenylphosphine oxide

The reaction of Ph3PO with LnCl3·nH2O (Ln=La–Lu≠Pm) in a 3.5:1 ratio in acetone produces [LnCl3(Ph3PO)3], whilst from a 6:1 ratio in ethanol the products are [LnCl2(Ph3PO)4]Cl·n(solvate). In the presence of [NH4][PF6] in ethanol solution, [LnCl2(Ph3PO)4]PF6 can be isolated. The last complexes are stable in solution but the [LnCl3(Ph3PO)3] and [LnCl2(Ph3PO)4]Cl partially interconvert in non-coordinating solvents, the neutral species being preferred by the lighter lanthanides, the cationic tetrakis complexes becoming more favoured towards the end of the series. The complexes have been characterised in the solid state by analysis and IR spectroscopy and in solution by 31P{1H} NMR spectroscopy and conductance measurements. The crystal structures of trans-[LnCl2(Ph3PO)4]Cl·nEtOH (Ln=Tb or Yb) and mer-[LnCl3(Ph3PO)3]·0.5Me2CO (Ln=La or Ce) are reported and discussed.

Optical absorption and NMR spectroscopic studies on paramagnetic trivalent lanthanide complexes with 2,2′-bipyridine.: The solvent effect on 4f–4f hypersensitive transitions

The optical absorption and NMR studies of trivalent lanthanide chloride complexes with 2,2′-bipyridine (bpy) are presented and discussed. The NMR spectra of paramagnetic complexes exhibit lower as well as higher field shifts of bpy resonances that reflect change in geometry and reveals importance of the factor ( 3 cos 2 θ−1 ) in changing sign of the shift. The paramagnetic shifts recorded have been analyzed and the intramolecular shift ratios suggest that the paramagnetic shift is predominantly dipolar in origin. Electronic spectral studies of the Pr, Nd, Ho, Er and Dy complexes in different solvents (viz. methanol, pyridine, DMSO and DMF), which differ with respect to donor atoms, reveal that the chemical environment around the lanthanide ion has great impact on f–f transitions and any change in the environment results in modifications of the spectra. The oscillator strength for the hypersensitive and non-hypersensitive transitions have been determined and changes in the oscillator strength and band shape with respect to solvent type is rationalized in terms of ligand (solvent) structure and coordination properties.

4 f–4 f hypersensitivity in the absorption spectra and NMR studies on paramagnetic lanthanide chloride complexes with 1,10-phenanthroline in non-aqueous solutions

The optical absorption and NMR studies of trivalent lanthanide chloride complexes with 1,10-phenanthroline (phen) are presented and discussed. The 1H NMR spectra of the complexes of La, Pr, Nd, Eu and Yb have been studied in methanol- d 4. The resonances of phen in the NMR spectra of the paramagnetic complexes have been shifted to lower as well as higher fields, which is a manifestation of dipolar interaction. The H (2) protons of the heterocyclic amine display broad resonances. The degree of broadening in Pr, Nd, and Yb complexes follows the order Pr<Nd<Yb. The inter- and intra-molecular shift ratios show that the paramagnetic shift is predominantly due to dipolar interaction. The electronic spectra of Pr, Nd, Ho and Er complexes have been investigated in methanol, pyridine, DMSO and DMF, which reveal that the hypersensitive transitions exhibit larger variation in oscillator strength values and band shapes. The change in the coordination geometry of the complexes and relative basicity of ligand are found responsible for oscillator strength and band shape variation. The interelectronic repulsion and covalency parameters show covalent nature of bonding between the metal and the ligand.

Synthesis and studies on reactivities of tetrahydrofurfurylcyclopentadienyl lanthanide chlorides CpsLnCl2·2THF (Ln=Dy, Ho, Gd) and Cps2LnCl·(Ln=Sm, Dy). The crystal structures of Cps2SmCl and Cps2Sm·(C3N2HMe2)

Abstract Reactions of lanthanide trichloride with two or one equivalent of tetrahydrofurfurylcyclopentadienyl (Cp s ) sodium salt in THF afford bis(tetrahydrofurfurylcyclopentadienyl)lanthanide chloride complexes Cp s 2 LnCl [Ln=Sm ( 1 ), Dy ( 2 )] and mono(tetrahydrofurfurylcyclopentadienyl)lanthanide dichloride complexes Cp s LnCl 2 ·2THF [Ln=Dy ( 3 ), Ho ( 4 ), Gd ( 5 )], respectively. Treatment of 1 with one equivalent of NaPzMe 2 (PzMe 2 =3,5-dimethylpyrazolate) forms Cp s 2 SmPzMe 2 ( 6 ). Complex 3 reacts with one equivalent of CpNa to yield the mixed-ring complex [Cp s CpDyCl] 2 ( 7 ). Complexes 1 – 7 have been characterized by elemental analyses, infrared and mass spectroscopies. The X-ray structural analyses show that 1 and 6 are unsolvated monomers. In complex 1 , the Sm atom is surrounded by two Cp s rings, one chlorine atom and two oxygen atoms of the side-chain to form a distorted trigonal bipyramid. The coordination number of central metal is nine. In complex 6 , the Sm atom is coordinated by two Cp s rings, two nitrogen atoms of 3,5-dimethylpyrazolate, and two oxygen atoms of the side-chain with a distorted tetragonal bipyramid geometry. The coordination number of the Sm atom is ten. The investigation result shows that the strong intramolecular chelating coordination and the high steric crowding result in the lower activity of 6 toward methyl methacrylate polymerization.

Syntheses of (C 4H 7OCH 2C 5H 4) 2LnCl (Ln = Nd, Gd, Dy, Yb) and crystal structure of (C 4H 7OCH 2C 5H 4) 2DyCl

The reaction of lanthanide trichlorides with sodium tetrahydrofur-furylcyclopentadienyl in THF afforded bis)tetrahydrofurfurylcyclopentadienyl)lanthanide chloride complexes (C 4H 7OCH 2C 5H 4) 2LnCl (Ln = Nd, Gd, Dy, Yb). All of the complexes where characterized by elemental analyses, IR and MS and the compound (C 4H 7OCH 2C 5H 4) 2 DyCl by X-ray crystallography. The molecular structure shows that the oxygen atoms in two η 5-C 4H 7OCH 2C 5H 4 groups are coordinated to Dy 3+, with DyO bond lengths of 2.434(7) and 2.459(8) Å, respectively.

Synthesis, characterization and scavenger effects of OH • and O −•2 radicals of lanthanide(III) complexes with pyruvic acid semicarbazone

Complexes of lanthanide chlorides with pyruvic acid semicarbazone (PASH), having the general formula Ln(PAS) 3· nH 2O (where Ln = La−Nd,Sm-Dy, Er, Yb; n = 1−3), have been synthesized and characterized on the basis of elemental analyses, IR spectra and thermal analyses. It has been found that the ligand and its complexes possess scavenger effects on OH • and O −• 2 radicals.

Synthesis and characterization of the complexes of lanthanide chlorides with N, N, N′, N′-tetraphenyl-3,6-dioxaoctanedioic diamide

The lanthanide chloride complexes with the ligand N, N, N′, N′-tetraphenyl-3,6-dioxaoctanedioic diamide (TDD) have been prepared in an ethanol-chloroform solution. These new complexes with general formula [Ln(TDD)Cl 2(H 2O) 2]Cl(Ln = La, Pr, Nd, Sm-Er) have been characterized by elemental analysis, conductivity measurements, IR spectra, f-f electronic spectra, 1H NMR spectra and TG-DTA techniques. In all the complexes, the ligand TDD shows quadridentate behaviour.

Syntheses and X-ray structures of bis(t-butylcyclopentadienyl) lanthanide chloride complexes [(Bu tCp) 2LnCl] 2 (Ln = Pr, Gd, Er)

Reaction of lanthanide trichlorides with two equivalents of sodium t-butyl-cyclopentadienide in THF gave rise to the bis(t-butylcyclopentadienyl)lanthanide chloride complexes [(Bu tCp) 2LnCl] 2 (Ln = Pr, Gd, Er), which were characterized by elemental analysis, IR and 1H NMR spectroscopy. In addition, the crystal structures of [(Bu tCp) 2PrCl] 2 ( 1) and [(Bu tCp) 2GdCl] 2 ( 2) were determined by single crystal X-ray diffraction at room temperature. The coordination number for Pr 3+ and Gd 3+ is 8 and the bond lengths PrCl and GdCl are 2.864(2) and 2.771(3) Å, respectively. The structural studies showed the complexes to have C 2h , symmetry.

Macrocycle complexation chemistry 32. Modification of the lanthanide ion coordination sphere via electrocrystallization of hydrated lanthanide chloride complexes of 12-Crown-4

Electrochemical techniques have been utilized to modify the crystallization of 12-crown-4 complexes of PrCl 3· nH 2O from CH 3CN:CH 3OH (3:1) solutions. [PrCl 3(OH 2)(12-crown-4)]·12-crown-4 crystallized from a 10:1 (12-crown-4:Pr) solution in the centric space group Pnma, with a = 23.338(7), b = 13.103(5), c = 7.713(4) Å and D calc = 1.74 g cm −3 for Z = 4. [PrCl 3(OHMe)(12-crown-4)] crystallized in the centric P 1 , with a = 7.486(3), b = 9.365(4), c = 11.268(4) Å, α = 91.92(3), β = 93.87- (3), γ = 102.00(3)° and D calc = 1.96 g cm −3 for Z = 2. Both complexes differ markedly from the series of 12-crown-4 early lanthanide chloride complexes that were obtained by slow evaporation ([M(OH 2) 5− (12-crown-4)]Cl 3·2H 2O).Utilization of an electrochemical cell produces complexes in which all three chloride anions are in the metal's primary coordination sphere, the coordination number is reduced, and most of the water or solvent molecules are eliminated.

Mono-condensed product of ferrocenylformyl acetone with ethylenediamine and its complexes of lanthanide chlorides

A mono-condensed product (Fcen) ▪ was obtained from the condensation of ferrocenylformyl acetone with ethylenediamine and five new Fcen complexes of lanthanide chlorides having the formula Fcen 3LnC1 3 (where Ln = La, Nd, Gd, Dy and Lu) were synthesized via the reaction of Fcen with lanthanides. These lanthanide complexes were characterized by microanalyses, IR, UV, Mössbauer spectra, molar conductivities and TG—DTA graphs. The 1H NMR and MS spectra of Fcen were also recorded. In these complexes each Fcen is tridentately coordinated to the lanthanide ions and three chlorine atoms are outer-sphere anions.

F-Element/crown ether complexes. 22. Preparation and structural characterization of lanthanide chloride complexes of 12-crown-4

[M(OH 2 ) 5 (12-crown-4)]Cl 3 •H 2 O (M=Ce, Nd, Sm, Eu, Gd, Y, Ho, Er) cristallise dans Pma2 1 . [YCl 2 (OH 2 )(OHMe)(12-crown-4)]Cl cristallise dans P1 [MCl 2 (OH 2 ) 2 (12-crown-4)]Cl (M=Dy, Ho, Er, Tm, Yb, Lu) cristallise dans P2 1 /m

Organometallic compounds of the lanthanides. 42. Bis(dimethoxyethane)lithium bis(cyclopentadienyl)bis(trimethylsilyl)lanthanide complexes

The trichlorides of Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu react with NaC/sub 5/H/sub 5/ in tetrahydrofuran in the presence of dimethoxyethane (dme) with formation of bis(cyclopentadienyl)lanthanide chloride complexes of the types (C/sub 5/H/sub 5/)/sub 2/Ln(/mu/-Cl)/sub 2/Na(dme). The reactions of these organolanthanide halide complexes with (trimethylsilyl)lithium in dme yield compounds of the type (Li(dme)/sub 2/)((C/sub 5/H/sub 5/)/sub 2/Ln(SiMe/sub 3/)/sub 2/) (Ln = Sm, Dy, Ho, Er, Tm, Lu). C/sub 5/H/sub 5//sub 2/Sm(/mu/-Cl)/sub 2/Na(dme) reacts with (trimethylgermyl)lithium in dme/pentane with formation of (Li(dme)/sub 3/)((C/sub 5/H/sub 5/)/sub 3/SmClSm(C/sub 5/H/sub 5/)/sub 3/) (7a.). The new compounds have been characterized by elemental analyses and IR and NMR spectra. The structure of (Li(dme)/sub 3/)(C/sub 5/H/sub 5/)/sub 3/SmClSm(C/sub 5/H/sub 5/)/sub 3/ (7a) has been elucidated through complete X-ray analysis. The crystals are monoclinic with a = 14.00 (1) /angstrom/, b = 13.38 (2) /angstrom/, c = 23.49 (3) /angstrom/, /beta/ = 93.37 (9)/degree/, space group P2/sub 1//n,Z = 4, and R = 0.0411 for 4671 reflections. The (Cp/sub 3/SmClSmCp/sub 3/)/sup /minus// anion consists of two Cp/sub 3/Sm units bridged by a chlorine atom with Sm-Cl distances of 2.827 (2) and 2.798 (2) /angstrom/.

Complexes of lanthanide chlorides with macrocyclic polyethers

Macrobicyclic polyether ligands I, II, III and IV have been shown [1] to form complexes with alkali salts having high formation constants even in water (10 5 l mol −1). Ln/Ligand La Nd Sm Gd I LaCl 3·I·2H 2O NdCl 3·I·H 2O GdCl 3·I·2H 2O II LaCl 3·II·2H 2O SmCl 3·II·H 2O GdCl 3·II·H 2O III LaCl 3·III·1.5H 2O NdCl 3·III·1.5H 2O SmCl 3·III· 1 2 H 2O GdCl 3·III·H 2O IV LaCl 3·IV·H 2O NdCl 3·IV·0.3H 2O GdCl 3·IV·H 2O ▪ These ligands provide potentially 7, 8, 8 and 9 oxygen atoms for coordination with a cation. We investigated the reaction between LaCl 3, NdCl 3, SmCl 3 and GdCl 3 and four ligands. Crystalline compounds were obtained all of stoichiometry LnCl 3:ligand = 1:1, as deduced from elemental analysis. The existence of crystals depends upon the presence of water, evidence of this was obtained from infra red spectra particularly in the 3000—3500 cm −1 region and from analysis. Preliminary X-ray diffraction measurements and the densities of laCl 3· II·xH 2O and LaCl 3·III·yH 2O gave values of x and y which are independent of elemental analysis. Summary of the compounds obtained. (see Table) A complete single crystal structure analysis of LaCl 3·II·H 2O has shown the crystals to contain (LaCl 2·II) + cations with the third chlorine ion and the water molecules occupying disordered sites in channels, similar to those in KCl·III·5H 2O[2] .