Complexes of dibenzylsulfoxide with lanthanide nitrate

A new series of dibenzylsulfoxide (DBSO) compounds of empirical formula [Ln(DBSO)_x(NO₃)₃] are reported, where x = 3 for Ln = Pr; x = 2.5 for Ln = Nd, Sm, Eu, Gd, Er and La; and x=2 for Ln = Dy. The compounds were synthesized from a non-aqueous solvent and isolated as dibenzylsulfoxide salts. Infrared spectral data established coordination by the anion groups and also that coordination of DBSO is through the oxygen. Additional information based on the nature of bonding and geometrical structure was obtained from the electronic absorption spectra, X-ray diffraction analysis, molecular conductivities and molecular weight measurements (as well as magnetic susceptibility measurements). All these physical measurements indicate octahedral coordination. The 20% decrease in the metal ion radius across the lanthanide series and the competition between DBSO and nitrate groups for the coordination site affect the number of DBSO molecules bonded to a tripositive lanthanide ion.     

Diethyl and diisopropyl phosphite complexes of lanthanide(III) chlorides

Lanthanide chlorides form adducts of the type [Ln(L)_nCl₃] (where Ln = La, Pr, Nd, Sm, Eu, when n = 6; and Ln = Gd, Tb, Dy or Yb when n = 5; and L = (EtO)₂P(O)H or (PrⁱO)₂P(O)H upon interacting with the diethyl and diisopropyl phosphites in dry ethyl and isopropyl alcohol, respectively. Complexes were recrystallised from ethanol or isopropanol and washed with n-hexane. On the basis of elemental analysis, infrared, ¹H NMR and ³¹P NMR spectral studies, it is concluded that these phosphites coordinate to the lanthanide metal atom through the oxygen atom which has the greatest affinity for lanthanides in these adducts.     

New complexes of La(III), Ce(III), Pr(III), Nd(III), Sm(III), Eu(III) and Gd(III) ions with morin

New solid complex compounds of La(III), Ce(III), Pr(III), Nd(III), Sm(III), Eu(III) and Gd(III) ions with morin were synthesized. The molecular formula of the complexes is Ln(C₁₅H₉O₇)₃ · nH₂O, where Ln is the cation of lanthanide and n = 6 for La(III), Sm(III), Gd(III) or n = 8 for Ce(III), Pr(III), Nd(III) and Eu(III). Thermogravimetric studies and the values of dehydration enthalpy indicate that water occurring in the compounds is not present in the inner coordination sphere of the complex. The structure of the complexes was determined on the basis of UV-visible, IR, MS, ¹H NMR and ¹³C NMR analyses. It was found that in binding the lanthanide ions the following groups of morin take part: 3OH and 4CO in the case of complexes of La, Pr, Nd, Sm and Eu, or 5OH and 4CO in the case of complexes of Ce and Gd. The complexes are five- and six-membered chelate compounds.     

Ultramicroporous channel lanthanide coordination polymers of 2,5-pyrazinedicarboxylate

Five lanthanide coordination polymers with composition {[Ln(pzdc)_1.5(H₂O)₃] · 0.5H₂O}_∞, (Ln = Pr, 1; Nd, 2; Sm, 3; Eu, 4; Gd, 5; pzdc = 2,5-pyrazinedicarboxylate), have been synthesized by reacting Ln(NO₃)₃ · 6H₂O with 2,5-pyrazinedicarboxylic acid under hydrothermal condition in the absence of additional base and characterized by elemental analysis, IR spectra and TG analysis, as well as single-crystal X-ray diffraction. They crystallize isostructurally in the triclinic space group P-1 and the cell parameters agree with the ionic radii of the Ln(III) ions. Each trivalent rare earth ion is nine coordinate in an N₂O₇ environment. The ligand 2,5-pyrazinedicarboxylate adopts three coordination modes, through which the lanthanide ions are linked together to form an infinite three dimensional structure. A 1D channel exists along the (1 0 0) direction which accommodates uncoordinated water by hydrogen bonds. Heating of 4 at 120 °C evacuated the uncoordinated water while retaining its single crystallinity with only minor change in cell parameters (crystal 6, [Eu(pzdc)_1.5(H₂O)₃]_∞). This hydrophilic ultramicroporous channel is selective to accommodate water only among common solvents, which has some potential interest for solvent separation.     

Structures and luminescent sensors of mixed‐counterions based salen‐type lanthanide coordination polymers

Reactions of N,N′‐bis (salicylidene)‐1,2‐cyclohexanediamine (H₂L) with mixed lanthanide counterions of LnCl₃·6H₂O and Ln (NO₃)₃·6H₂O afford six H₂L lanthanide coordination polymers, e.g. {[Pr(H₂L)₂(NO₃)₂Cl]·2CH₂Cl₂}_n ( 1 ); {[Ln(H₂L)_1.5(NO₃)₃]₂·5CHCl₃·mCH₃OH}_n [Ln = Sm ( 2 ), Eu ( 3 ), Gd ( 4 ), Tb ( 5 ) and Yb ( 6 ); m = 1 ( 2 – 5 ); m = 0 ( 6 )]. X‐ray crystallographic analysis reveals that complex 1 exhibits three‐dimensional diamondoid topologic structure and complexes 2 – 6 are of two‐dimensional structure. Luminescent spectra show that complexes 1 and 6 have characteristic near‐infrared (NIR) emission of praseodymium (III) and ytterbium (III) ions and complexes 2 – 5 emit luminescence in the visible region. Complexes 3 and 6 reveal sensitive luminescence responses to formaldehyde.     

Synthesis and coordination chemistry of tripodal dialkyl[1,2-bis(diethylcarbamoyl)ethyl]phosphonates with lanthanide nitrates

Trifunctional dialkyl [1,2-bis(diethylcarbamoyl)- ethyl] phosphonates, (RO)₂P(O)CH[C(O)N(C₂H₅)₂]- [CH₂C(O)N(C₂H₅)₂] R  CH₃, C₂H₅, i-C₃H₇, n-C₆H₁₃ were prepared from the respective sodium salts, Na[(RO)₂P(O)CHC(O)N(C₂H₅)₂] and N,N- diethylchloroacetamide, and they were characterized by elemental analysis, mass, infrared and NMR spectroscopy. The molecular structure of (i-C₃H₇O)₂- P(O)CH[C(O)N(C₂H₅)₂][CH₂C(O)N(C₂H₅)₂] was determined by single crystal X-ray diffraction analysis and found to crystallize in the monoclinic space group P2₁/c with a=15.589(6), b=9.783(4), c= 16.283(7) Å, β = 110.90(3)°, Z = 4 and V= 2320(2) ų. The structure was solved by direct methods and blocked least-squares refinement converged with Rf = 5.7% and R_wF= 4.4% on 2266 unique data with F>4σ(F). Important bond distances include PO 1.459(3) Å, CHCO 1.228(3) Å and CHCH₂CO 1.223(3) Å. The coordination chemistry of the ligand with several lanthanides was examined, and the structure of the complex Gd(NO₃)₃{[(i-C₃H₇O)₂P(O)CH[C(O)N(C₂H₅)₂][CH₂C(O)N(C₂H₅)₂]}₂·H₂O was determined. The complex crystallized in the monoclinic space group P2₁/n with a = 13.524(5), b = 22.033(4), c = 19.604(4) Å β = 106.22(2)°, Z = 4 and V= 5609(3) ų. The structure was solved by heavy atom techniques and blocked least-squares refinement converged with R_F = 5.9% and R_wF = 4.1% on 5275 reflections with F > 4σ(F). Both trifunctional ligands were found to bond to Gd(III) through only the phosphoryl oxygen atoms. The remainder of the Gd coordination sphere was composed of three bidentate nitrate oxygen atoms and an oxygen bonded water molecule. Several important bond distances include GdO(phosphoryl)_av = 2.343(5) Å, GdO(nitrate)_av = 2.475(7) Å, GdO(water) = 2.354(5) Å, PO(phosphoryl)_av = 1.467(6) Å, CHCO_av = 1.242(10) Å and CHCH₂CO_av = 1.209(11) Å.     

Effect of auxinhormone lanthanide complexes on the growth of wheat coleoptile

Naphthalene-1-acetic acid (HNAA), dichlorophenoxy acetic acid (HDAA), and indole-3-acetic acid (HIAA) are auxinhormones that can affect the growth of plants. The lanthanide complexes of the above auxinhormone LnA₃-3H₂O (Ln = La³⁺, Ce³⁺, Sm³⁺, Er³⁺, Yb³⁺; HA = HNAA, HDAA, HIAA; A = NAA^-, DAA^-, IAA^-) were synthesized and are characterized in this paper. The solubility and IR spectra of these complexes were also studied. Experiments of the effects of LnCl₃-nH₂O, HA, and LnA₃-3H₂O on the growth rate of wheat coleoptile sections show, that LnCl₃-nH₂O promotes the growth of wheat coleoptile when this compounds concentration is lower than 2 x 10^-5 M and the promotion is very significant when the concentration of Ln³⁺ is lower than 8 x 10^-6 M. It was also found that the effect of LnA₃· 3H₂O on the growth of wheat coleoptile is stronger than that of LnCl₃·nH₂O and HA, which indicates that the combination of Ln³⁺ with HA act synergistically.     

Studies on copper(II) complexes of o-quinone monooximes. 4. Interaction between aquobis(1,2-naphthoquinone 1-oximato)copper(II) and lanthanide(III) ions. New heteropolynuclear complexes containing CuII and LnIII

By reacting aquobis(1,2-naphthoquinone 1-oximato)copper(II) [Cu(nqo)₂·H₂O] with lanthanide chlorides, new heteropolynuclear complexes containing both Cu^II and Ln^III (Ln^III = La^III, Nd^III) were obtained. The compounds have been characterized by elemental and thermogravimetric analysis, electron microprobe analysis, and electronic and vibrational spectral data. A different Cu^II complex, containing nqo ligands and ionic perchlorate but no lanthanide ions, was obtained by reaction of Cu(nqo)₂·H₂O with lanthanide perchlorates.     

Complexes of triphenylphosphine oxide with lanthanide bromides

The reaction between hydrated lanthanide bromides and triphenylphosphine oxide in 1:3 and 1:4 ratios in ethanol gave a series of complexes [LnBr₂(Ph₃PO)₄]Br (Ln = Pr, Nd, Gd, Tb, Er, Yb, Lu) which contain ethanol and water in the lattice, regardless of the ratio of reactants used. The single crystal X-ray structures of [NdBr₂(Ph₃PO)₄]Br, [GdBr₂(Ph₃PO)₄]Br and [YbBr₂(Ph₃PO)₄]Br have been determined and have an octahedral geometry about the metal ion. Analysis of the bond distances shows that the Ln-O and Ln-Br distances change in accord with the lanthanide contraction, but the non-bonded Ln?P distances and the Ln-O-P angles differ significantly for the Yb complex. Conductivity and variable temperature ³¹P NMR measurements in dichloromethane indicate that the complexes dissolve as [LnBr₂(Ph₃PO)₄]⁺ for the lighter lanthanides with further ionisation becoming progressively more important for the heavier metals. In methanol more extensive dissociation is apparent. The electrospray mass spectra obtained from methanol solution show [LnBr₂(Ph₃PO)₄]⁺ is present in high abundance in the gas phase with other species formed due to ligand redistribution, ionisation and solvolysis.     

Aminopolycarboxylates of rare earths. 13. The apparent molal volumes of the lanthanide(III), cobalt(III) and chromium(III) ethylenediamine tetraacetate complexes

The apparent molal volumes of the complexes KLnedta (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Er and Yb), KCoedta and KCredta were determined from density measurements. The apparent molal volumes of the complexes KLnedta show a non-monotonous change with increasing atomic number; there is a significant increase in the values between Nd and Gd. To explain the observed trend, a structural change is postulated to take place gradually on progressing from Gd towards La. With increasing ionic size, there is an increase in the metal-ligand bond distances and in the mobility of the functional groups, resulting in a jump in the number of coordinated water molecules by one between Gd and Nd. There is a further increase in the hydration of the central ions, connected with the gradual de-coordination of a carboxylate group. As a result of the gradual structural change there is one free carboxylate group on average in Laedta^? and about four water molecules are coordinated in the inner sphere, while in the complexes of the elements heavier than Gd the ligand is hexadentate and only two water molecules are in the inner sphere. The apparent molal volumes of KCoedta and KCredta are practically equal and are higher than those of the lanthanide complexes; this has been explained by the stronger hydration and the more significant water-ordering effect of the Ln³⁺ ions coordinated in the complexes Lnedta^?.The postulated structural changes correlate with the trend of the protonation constant values, as well as with the results of ¹H NMR studies on the complexes Lnedta^?.     

Synthesis,crystal structure and fluorescent characterization of a novel lanthanide tetraphosphonate with a layered structure

Hydrothermal reactions of Gd(III) nitrate with N,N,N′,N′-tetramethylenephosphono-1,4-diaminobutane, (H₂O₃PCH₂)₂N–(CH₂)₄–N(CH₂PO₃H₂)₂ (H₈L), afforded a novel Gd(III) phosphonate, namely, Gd[(O₃PCH₂)(HO₃PCH₂)N(H)(CH₂)₄N(H)(CH₂PO₃H)₂] · 2H₂O, [Gd(H₅L)] · 2H₂O. Its structure was established by a single-crystal X-ray diffraction study. In this compound, the Gd(III) ion is coordinated by eight phoshonate oxygen atoms from five different phosphonate groups, which belong to five different phosphonic ligands. Each Gd atom is connected with its neighboring Gd atoms by two phosphonate oxygens, forming a gadolinium phosphonate slab along the a-axis. Such slabs are bridged by tetraphosphonate H₅L anions, resulting in a 〈0 1 1〉 layer with the butane groups toward the interlayer space. These layers are further interlinked by strong hydrogen bonds formed by uncoordinated phosphonate oxygens into a 3D supermolecular structure. Luminescent studies indicate that this compound exhibits a broad blue fluorescent emission band at 441 nm.     

The mononuclear and dinuclear dimethoxyethane adducts of lanthanide trichlorides [LnCl3(DME)2]n, n=1 or 2, fundamental starting materials in lanthanide chemistry: preparation and structures

Some new dimethoxyethane (DME) adducts of lanthanide trichlorides of formula [LnCl₃(DME)₂]_n, n=1 or 2; (n=2, Ln=La, Ce, Pr, Nd; n=1, Ln=Eu, Tb, Ho, Tm, Lu) have been prepared by treating Ln₂O₃, or LnCl₃ · nH₂O, or Ln₂(CO₃)₃, in DME as medium, with thionyl chloride at room temperature, eventually in the presence of water in the case of Ln₂O₃ and Ln₂(CO₃)₃. The complexes from lanthanum to praseodymium included are chloro-bridged dimers. In the case of neodymium, the new results complement the literature data, showing that both the mononuclear and dinuclear species exist: neodymium can therefore be regarded as the turning element from dinuclear to mononuclear structures along the series. Only mononuclear complexes were isolated in the Eu-Lu sequence. The lanthanide contraction has been evaluated on the basis of the Ln-O and Ln-Cl bond distances on the isotypical series of the mononuclear complexes LnCl₃(DME)₂ covering a range of 12 atomic numbers.     

2D network coordination polymers of lanthanide with N-(2-pyridylmethyl)iminodiacetic acid: Hydrothermal syntheses, crystal structures and luminescent properties

Six lanthanide two-dimensional network coordination polymers with the general formula of [Ln(pmida)(NO₃)(H₂O)]_n, where Ln = La (1), Nd (2), Sm (3), Gd (4), Dy (5), Er (6) and pmida²⁻ = N-(2-pyridylmethyl)iminodiacetate, have been synthesized by hydrothermal process and characterized by elemental analysis, Infrared spectroscopy, thermogravimetric analysis and single-crystal X-ray diffraction. All crystals are isostructural and crystallize in the monoclinic space group P2₁/a. The lanthanide(III) ion is nine-coordinated in a geometry of distorted tricapped trigonal prism by two N atoms and two O atoms from one pmida²⁻ ligand, two bridging carboxylate O atoms from other two pmida²⁻ ligands, two O atoms of a bidentate chelating nitrate and a O atom of a coordinated water molecule. The luminescent properties of [Sm(pmida)(NO₃)(H₂O)]_n (3) and [Dy(pmida)(NO₃)(H₂O)]_n (5) were investigated.     

f-element/crown ether complexes. 6. Interaction of hydrated lanthanide chlorides with 15-crown-5: Crystallization and structures of [M(OH2)8]Cl3·(15-crown-5) (M = Gd,Lu)

The interaction of hydrated chloride salts of Gd³⁺ and Lu³⁺ with 15-crown-5 in a 1:3 mixture of CH₃OH:CH₃CN produces crystalline [M(OH₂)₈]Cl₃· (15-crown-5) (M = Gd, Lu). The crystal and molecular structures of both complexes have been determined by single crystal X-ray diffraction. Both are isostructural with previously determined Y analog and crystallize in the monoclinic space group P2₁/n with Z = 4. Lattice parameters are a = 9.247(4), b = 17.312(5), c = 15.191(6) Å, β = 92.19(3)°, D_calc = 1.72 g cm⁻³ for M = Gd and a = 9.150(1), b = 17.171(1), c = 15.217(1) Å, β = 92.64(1)°, D_calc = 1.80 g cm⁻³ for M = Lu. Each complex was refined by least-squares to final conventional R values of 0.052 (M = Gd, 2932 observed [F_o⩾5σ(F_o) reflections) and 0.036 (M = Lu, 3313 observed reflections). The octaaquo M(III) ions exist as a distorted dodecahedron with average MOH₂ separations of 2.41(4) Å (M = Gd) and 2.35(4) Å (M = Lu). The crown ether molecule is hydrogen bonded to metal coordinated water molecules to form polymeric chains along b. The remaining water molecule hydrogen atoms participate in hydrogen bonds with the chloride ions essentially in the ac plane. Two resolvable disordered crown ether conformations are observed with occupancies of 60%/40% (M = Gd) and 75%/25% (M = Lu).     

P.M.R studies on fully methylated aldohexopyranosides and their 6-deoxy analogues using lanthanide shift reagents

The complexes of lanthanide shift reagents (LSR) with permethylated aldo-hexopyranosides and their 6-deoxy analogues having the gluco, galacto, and manno configurations have been studied. On the basis of shift data from Eu(fod)₃ and Pr(fod)₃, and broadening data from Gd(fod)₃, it was found that the LSR bind preferentially to two neighbouring MeO-oxygens having the axial-equatorial relationship. Because of its steric requirements, the C-5 substituent hinders the binding increasingly in the following order: O-2(ax)-O-3(eq)<O-1(ax)-O-2(eq)<O-4(ax)-O-3(eq). Equatorial groups bind the LSR only weakly. Strong binding to O-6 was found when MeO-6 is predominantly “axially” oriented; when this group has the “equatorial” position, O-6 is not favoured over any other equatorial oxygen. In view of the preference of the LSR to bind to an O(ax)-O(eq) site, it is proposed that O-5 is involved in the binding to the axial O-6. Eu(fod)₃ seems to have less tendency to bind to the O-6(ax)-O-5 site than the other two LSR.     

Heterobinuclear Zn‐Ln (Ln = La,Nd, Eu,Gd, Tb,Er and Yb) complexes based on asymmetric Schiff‐base ligand: synthesis,characterization and photophysical properties

With a novel asymmetric Schiff‐base zinc complex ZnL (H₂L = N‐(3‐methoxysalicylidene)‐N′‐(5‐bromo‐3‐methoxysalicylidene)phenylene‐1,2‐diamine), obtained from phenylene‐1,2‐diamine, 3‐methoxysalicylaldehyde and 5‐bromo‐3‐methoxysalicylaldehyde, as the precursor, a series of heterobinuclear Zn‐Ln complexes [ZnLnL(NO₃)₃(CH₃CN)] (Ln = La, 1; Ln = Nd, 2; Ln = Eu, 3; Ln = Gd, 4; Ln = Tb, 5; Ln = Er, 6; Ln = Yb, 7) were synthesized by the further reaction with Ln(NO₃)₃·6H₂O, and characterized by Fourier transform‐infrared, fast atom bombardment mass spectroscopy and elemental analysis. Photophysical studies of these complexes show that the strong and characteristic near‐infrared luminescence of Nd³⁺, Yb³⁺and Er³⁺ with emissive lifetimes in the microsecond range has been sensitized from the excited state of the asymmetric Schiff‐base ligand due to effective intramolecular energy transfer; the other complexes do not show characteristic emission due to the energy gap between the chromophore and lanthanide ions. Copyright © 2012 John Wiley & Sons, Ltd.     

Complexes of lanthanoid salts with macrocyclic ligands. Part 32. Synthesis and characterization of the complexes between lanthanoid nitrates and a tetraoxadiaza macrocycle

Lanthanoid nitrates react with 1,7,10,16-tetraoxa- 4,13-diaza-N,N′-dimethylcyclooctadecane, Me₂(2,2), to give complexes with two different metal:ligand ratios, 1:1 (Ln = La, Ce, Tb) and 4:3 (Ln = Pr, Nd, Sm, Eu, Gd, Th, Dy, Ho). The complexes were isolated from anhydrous solutions in acetonitrile and characterized by elemental analysis, X-ray diffraction, magnetic susceptibility measurements and vibrational analysis.The La and Ce 1:1 complexes are non-ionic and probably 12-coordinated, with the metal ion bound to the six donor atoms of the ligand and to three bidentate nitrate ions. The 4:3 complexes are ionic; they contain three bis(nitrato) complex cations [Ln(NO₃)₂·Me₂(2,2)]⁺ and one hexakis(nitrato) anion [Ln(NO₃)₆]³⁻. Spectroscopic data, including luminescence spectra, point to the 1:1 Tb-complex as being a 4:3 complex with an additional outer-sphere coordinated molecule of ligand.In solution, the 1:1 complexes remain essentially non-ionic, although some dissociation cannot be ruled out, whereas the 4:3 complexes behave as 2:1 (of even 3:1) electrolytes.     

f-Element/crown ether complexes. 26. Crystallization of two hydrated forms of hydrogen bonded complexes of NdCl3·nH2O and 15-crown-5. Crystal structures of [Nd(OH2)9]Cl3·15-crown-5·H2O and [NdCl2(OH2)6]Cl·15-crown-5

When slowly evaporated, the reaction of NdCl₃· nH₂O with 15-crown-5 in a 3:1 mixture of acetonitrile:methanol produces two crystalline hydrates. The decahydrate, [Nd(OH₂)₉]Cl₃·15-crown-5·H₂O, is orthorhombic, P2₁2₁2₁, with (at −150 °C) a = 10.571(4), b = 15.220(7), c = 15.686(7) Å, and D_calc = 1.71 g cm⁻³ for Z = 4. These crystals are stable to the moisture in air. Each Nd is nine-coordinate with tricapped trigonal prismatic geometry. The nine coordinated water molecules are hydrogen bonded to two symmetry related crown ethers, all three chloride ions, and the tenth water molecule. The crown has a total of six hydrogen bonds, four on one side (two to a single oxygen atom) and two on the other. This ether exhibits conformational disorder. The hexahydrate, [NdCl₂(OH₂)₆]Cl·15-crown-5 is deliquescent, dissolving in air and recrystallizing as [NdCl₂(OH₂)₆]Cl. Crystals of this complex are monoclinic, P2₁/n, with (at 20 °C) a = 9.821(3), b = 16.978(9), c = 12.849(8) Å, β = 94.06(5)°, and D_calc = 1.80 g cm⁻³ for Z = 4. The Nd atom exists in a distorted dodecahedral geometry with one chlorine in an A site and one in a B site. The coordinated chlorine atoms accept hydrogen bonds producing polymeric zigzag hydrogen bonded chains along c. The third noncoordinated chloride ion accepts four hydrogen bonds, three from one formula unit and one from a second formula unit related by a unit translation along a. The crown ethers accept five hydrogen bonds, two on one side, and three on the other, thus separating the zigzag chains along b.     

Coordination chemistry of lanthanides with cryptands. An X-ray and spectroscopic study of the complex Nd2(NO3)6 [C18H36O6N2]·H2O

By reacting neodymium nitrate hexahydrate with the cryptand 〈222〉 in methanol, the complex Nd₂-(NO₃)₆[C₁₈H₃₆O₆N₂]·H₂O was obtained and analyzed by single-crystal X-ray diffraction. The cell is triclinic P$\text{1}$ with a = 14.870(2) Å, b = 13.261(2) Å, c = 8.832(1) Å, α = 91.2(1)°, β = 93.4(1)°, γ = 87.6(1)°, Z = 2 and U = 1736.6 ų. The structure was refined by least-squares methods to the conventional R = 0.039 for 6177 observed reflections. The compound contains the cations [Nd〈222〉(NO₃)]²⁺ and the anions [Nd(NO₃)₅·H₂O]^2?, and is isostructural with the samarium analogue. Solid state fluorescence spectra of the title complex were measured at room and liquid nitrogen temperature, and the transitions ⁴F_3/2 → ⁴I_9/2 and ⁴F_3/2 → ⁴I_11/2 analyzed.