Sc(III), Eu(III), and Gd(III) Complexes with Macrocyclic Cavitand Cucurbit[6]uril: Synthesis and Crystal Structures

Slow evaporation of solutions of Sc and Eu nitrates with macrocyclic cavitand cucurbit[6]uril gives crystals of isostructural complexes [Sc(NO₃)(H₂O)₄(C₃₆H₃₆N₂₄O₁₂)](NO₃)₂ ? 8.5H₂O (space group Pna2₁, a = 32.0065(18) Å, b = 14.7904(8) Å, c = 11.5774(6) Å, V = 5480.6(5) ų, Z = 4) and [Eu(NO₃)(H₂O)₄(C₃₆H₃₆N₂₄O₁₂)](NO₃)₂ ? 6.75H₂O (space group Pna2₁, a = 31.9525(17) Å, b = 14.7203(8) Å, c = 11.8592(6) Å, V = 5578.0(5) ų, Z = 4). The metal to ligand ratio in these complexes is 1 : 1; the complexes are obtained at 0.025–0.1 mol/l concentrations of the metals in solutions. With higher lanthanide concentrations (0.7–1 mol/l), the 2 : 1 complex with cucurbit[6]uril is formed of the composition [{ Gd(NO₃)(H₂O)₅}₂(C₃₆H₃₆N₂₄O₁₂)](NO₃)₄ ? 6.5H₂O (space group \(P\bar 1\), a = 13.3972(6) Å, b = 14.4994(5) Å, c = 18.3290(8) Å, α = 73.5610(10)°, β = 87.2590(10)°, γ = 87.5540(10)°, V = 3409.4(2) ų, Z = 2) and isotypical complex [{Gd(NO₃)(H₂O)₅}₂{(C₅H₅N) ? (C₃₆H₃₆N₂₄O₁₂)}](NO₃)₄ ? 8H₂O with a pyridine molecule inside the cucurbit[6]uril cavity (space group P2₁/n, a = 14.8263(6) Å, b = 13.3688(7) Å, c = 18.5970(9) Å, β = 107.5860(10)°, V = 3513.8(3) ų, Z = 2). According to X-ray diffraction data, the metal atoms of the title complexes coordinate the O atoms in portals of cucurbit[6]uril molecules.     

Use of the macrocyclic ligand cucurbit[6]uril for isolation of tetranuclear lanthanide aquahydroxo-carboxylate complexes from aqueous solutions

The tetranuclear lanthanide complexes {[Ln₄(μ₃-OH)₄(μ₂-OH)₂(C₅NH₄COO)₂ (H₂O)₄-(C₃₆H₃₆N₂₄O₁₂)₂][Ln(H₂O)₈]_1.5[Ln(H₂O)₆(NO₃)₂]_0.5} (NO₃)₉·nH₂O (Ln = Ho, Gd, or Er) were prepared by heating (130 °C) aqueous solutions of lanthanide nitrates, cucurbit[6]uril (C₃₆H₃₆N₂₄O₁₂), and 4-cyanopyridine. The tetradentate coordination of the macrocyclic cucurbit[6]uril ligands through the portals leads to the formation of sandwich compounds, in which the tetranuclear hydroxo complex is located between two macrocyclic molecules. The polynuclear complexes are additionally stabilized by the chelating effect of the isonicotinate ligands generated by hydrolysis of 4-cyanopyridine. In the complexes, the aromatic moiety of the isonicotinate ion is encapsulated into the hydrophobic inner cavity of cucurbit[6]uril. In the absence of cucurbit[6]uril, the reaction with 4-cyanopyridine produces only the polymeric complexes [Nd(C₅NH₄COO)₃(H₂O)₂] and [Ln(C₅NH₄COO)₂(H₂O)₄]NO₃ (Ln = Pr, Sm, or Gd), whose structures were established by X-ray diffraction. In water and aqueous solutions of nonionic and cationic surfactants, irreversible changes of the tetranuclear fragment of the complex (Ln = Gd) were observed after storage for two days, whereas the anionic surfactant stabilizes the complexes. Dedicated to Academician O. M. Nefedov on the occasion of his 75th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1885–1894, November, 2006.     

Coordination of Bimuth(III) to Cucurbit[8]uril. Preparation and X‐ray Structure of [{Bi(NO3)(H2O)5}2(Q8)][Bi(NO3)3(H2O)4]2[Bi(NO3)5]2·Q8·19H2O

Bi(NO₃)₃ reacts with cucurbit[8]uril, (Q8), in 3M HNO₃ to give the title complex whose structure includes three discrete Bi complexes: [{Bi(NO₃)(H₂O)₅}₂(Q8)]⁴⁺ (CN of Bi = 9, both NO₃^— and cucurbit[8]uril are bidentate), [Bi(NO₃)₅]^2— (CN of Bi = 10, all NO₃^— are bidentate), and [Bi(NO₃)₃(H₂O)₄] (CN of Bi = 10, all NO₃^— are bidentate).     

Crystal structure of a La(III) complex with macrocyclic cavitand cucurbit[6]uril

Slow evaporation in air of a lanthanum nitrate solution containing macrocyclic cavitand cucurbit[6]uril yields a complex of the composition of [La(H₂O)₆(X@C₃₆H₃₆N₂₄O₁₂)(NO₃)](NO₃)₂· 6.96H₂O (X = 0.5C₅H₅N + 0.5H₂O). The complex is structurally characterized using single crystal X-ray diffraction. Lanthanum atoms are coordinated with oxygen atoms of carbonyl groups of cucurbit[6]uril portals. The compound crystallizes in the orthorhombic crystal system, space group Pnn2, unit cell parameters (150 K): a = 11.997(2) Å, b = 17.093(3) Å, c = 14.133(3) Å, V = 2899.3(10) ų, Z = 2. Lanthanum atoms are disordered, alternative positions being related by the two-fold axis. The complex has an island structure. A pyridine molecule occupies an internal cavity of one half of cucurbit[6]uril molecules, while a water molecule occupies the other.     

Synthesis and crystal structure of a supramolecular adduct of the aqua nitrato complex of gadolinium [Gd(NO<Subscript>3</Subscript>)(H<Subscript>2</Subscript>O)<Subscript>7</Subscript>]<Superscript>2+</Superscript> with macrocyclic cavitand cucurbit[6]uril

A supramolecular adduct of gadolinium aqua nitrato complex and cucurbit[6]uril { [Gd(NO₃)(H₂O)₇](C₅H₅N)@(C₃₆H₃₆N₂₄O₁₂)}(NO₃)₂·10H₂O is obtained by slow diffusion of methanol into an aqueous solution containing gadolinium nitrate, pyridine, and cucurbit[6]uril. According to single crystal X-ray diffraction data, water molecules coordinated to metal atom make hydrogen bonds to polarized carbonyl groups of the macrocycle. The heptaaquanitratogadolinium(III) [Gd(NO₃)(H₂O)₇]²⁺ cation is structurally characterized for the first time. Crystal system is triclinic, space group \(P\overline 1 \), a = 12.3137(4) Å, b = 14.2334(5) Å, c = 19.5629(6) Å; α = 80.850(1)°, β = 86.879(1)°, γ = 68.855(1)°; V = 3157.15(18) ų, Z = 2. Oriented hydrogen-bonded chains of alternating cucurbit[6]uril molecules and gadolinium aqua cations form in the crystal structure.     

Synthesis and crystal structures of sumpramolecular compounds of cucurbit[n]urils (n = 6, 8) with polynuclear strontium aqua complexes

Crystals of the {[Sr₄(H₂O)₁₂(NO₃)₄](C₃₆H₃₆N₂₄O₁₂)}(NO₃)₄·3H₂O and {[Sr₂(H₂O)₁₂][Sr(H₂O)₃(NO₃)₂]₂(C₄₈H₄₈N₃₂O₁₆)}(NO₃)₄·8H₂O were prepared by slow concentration of aqueous solutions containing strontium nitrate and macrocyclic cavitands, viz., cucurbit[6]uril and cucurbit[8]uril ([C₆H₆N₄O₂] _n , n = 6 and 8), respectively. According to the results of X-ray diffraction analysis, the crystal structures of these supramolecular compounds are built from polymeric chains, which consist of the alternating cucurbit[n]uril molecules and Sr²⁺ cations linked through the bridging aqua ligands and nitrate anions. The supramolecular compound of cucurbit[8]uril provides the first example of compounds in which this macrocycle is bound to metal aqua complexes.     

Anion encapsulation by Ln(III)/K(I) heterobismetal-capped cucurbit[5]uril

Three Ln(III)/K(I) (Ln = La, Ce and Nd) heterobismetal-capped cucurbit[5]uril molecular capsules, {[LaK(C₃₀H₃₀N₂₀O₁₀)Cl]Cl(H₂O)₃}Cl₂·8H₂O (1), {[CeK(C₃₀H₃₀N₂₀O₁₀)Cl]Cl(H₂O)₃}Cl₄(H₃O)₂ ^2 + ·8H₂O (2) and {[NdK(C₃₀H₃₀N₂₀O₁₀)Cl]Cl(H₂O)₃}Cl₂·12.5H₂O (3), were synthesised by self-assembly in aqueous solution, and their anion encapsulation property was confirmed by X-ray crystallography. The effect of the lanthanide cation radius on the structure of the heterobismetal-capped cucurbit[5]uril molecular capsules has been investigated.     

New lanthanide-based complexes constructed from cucurbit[6]uril: Synthesis,structures and properties

Three lanthanide-based complexes, {Gd₂(H₂O)₁₀(CB[6])₂}·CB[6]·6Cl·12H₂O (1), {[Gd₂(H₂O)₈CB[6]₂]·(CuCl₄)·4Cl·46H₂O}_n (2), and {Dy₂(NO₃)₂(H₂O)₁₀(CB[6])}·4NO₃·14H₂O (3) (CB[6] = cucurbit[6]uril), were prepared with cucurbit[6]uril (CB[6]). These complexes were characterized by single-crystal X-ray diffraction, elemental analysis, FT-IR spectroscopy, UV–Vis spectroscopy, thermogravimetric analysis and magnetization measurements. Crystallographic results showed that 1 and 3 are dinuclear and crystallize in the triclinic space group Pī, whereas 2 is a 1-D zigzag supramolecular chain that crystallizes in the monoclinic system in C2/c. The results indicated that temperature has a big effect on the supramolecular assemblies and a different structure inducer also leads to the formation of different coordination polymers. Frequency dependence in the ac susceptibility signals was observed in 3.     

Insights into crystal structures,supramolecular architectures and antioxidant activities of self-assembled fluorescent hetero-multinuclear [Cu (II)-Ln (III)] (Ln = La,Ce, Pr and Nd) salamo-like complexes

Newly designed hetero-dinuclear 3d–4f complex [Cu(L)La (NO₃)₂(μ-NO₃)(H₂O)]·EtOH ( 1 ), hetero-tetranuclear 3d–4f complex [Cu(L)Ce (NO₃)₂(μ-NO₃)(OAc)₂]₂·MeOH ( 2 ) and hetero-multinuclear 3d–4f complexes [{Cu(L)Ln (NO₃)₃}₂][Cu(L)Ln (NO₃)₃]₂ (Ln = Pr ( 3 ) and Nd = ( 4 )) have been self-assembled from the reaction of Cu (OAc)₂·H₂O, Ln (NO₃)₃·6H₂O (Ln = La, Ce, Pr and Nd) with an unsymmetric salamo-like bisoxime ligand H₂L (6-Methoxy-6′-ethoxy-2,2′-[ethylenedioxybis (nitrilomethylidyne)]diphenol) based on a Schiff base condensation of 2-[O-(1-ethoxyamide)]oxime-6-methoxyphenol and 3-ethoxysalicylaldehyde. The structures of complexes 1 – 4 were characterized by elemental analyses, PXRD analyses, IR, UV–Vis spectra, and single-crystal X-ray analyses. In addition, the supramolecular interactions and fluorescence properties of complexes 1 – 4 are discussed in detail. Moreover, the antioxidant activities of the complexes 1 – 4 were determined by superoxide radical-scavenging method in vitro, which indicates that the complexes 1 – 4 all show potential antioxidant properties.     

Synthesis and crystal structures of supramolecular compounds of polynuclear aluminum(III) aqua hydroxo complexes with cucurbit[6]uril

Supramolecular compounds of the di-, trideca-, and triacontanuclear aluminum aqua hydroxo complexes, viz., [Al₂(OH)₂(H₂O)₈]⁴⁺, [Al₁₂(AlO₄)(OH)₂₄(H₂O)₁₂]⁷⁺, and [Al₃₀O₈(OH)₅₆(H₂O)₂₆]¹⁸⁺, respectively, with the organic macrocyclic cavitand cucurbit[6]uril (C₃₆H₃₆N₂₄O₁₂) were prepared by evaporation of aqueous solutions of aluminum nitrate and cucurbit[6]uril after the addition of pyridine, ammonia, KOH, or NaOH at pH 3.1–3.8. X-ray diffraction study demonstrated that the aqua hydroxo complexes are linked to the macrocycle through hydrogen bonds between the hydroxo and aqua ligands of the polycations and the portal oxygen atoms of cucurbit[6]uril. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 261—268, February, 2006.     

Supramolecular approach to crystallization of polynuclear chromium(III) aqua hydroxo complexes: synthesis and crystal structures of complexes [Cr2(OH)2(H2O)8]4+ and [Cr4(OH)6(H2O)12]6+ with cucurbit[n]uril (n = 7, 8)

Supramolecular compounds of the compositions {[Cr₂(OH)₂(H₂O)₈](C₄₂H₄₂N₂₈O₁₄)₂}-(NO₃)₄·18.75H₂O (1) and {[Cr₄(OH)₆(H₂O)₁₂](C₄₈H₄₈N₃₂O₁₆)₃(NO₃)₆·55H₂O (2) were synthesized from aqueous solutions of chromium(III) nitrate and the macrocyclic cavitand cucurbit[n]uril (C_6n H_6n N_4n O_2n , where n = 7 or 8, respectively). According to the X-ray diffraction study, the polynuclear chromium aqua complexes are disposed in cavities formed by the cucurbit[n]uril molecules and are linked to these molecules through hydrogen bonds between the hydroxo and aqua ligands of the polycations and the portal oxygen atoms of the macrocycles. Compound 1 is the first example of supramolecular compounds of cucurbit[7]uril with metal aqua complexes. The isolation of the supramolecular adduct with cucurbit[8]uril 2 in the single-crystalline state allows the determination of the structure of the tetranuclear chromium aqua complex having an adamantane-like structure, [Cr₄(μ₂-OH)₆(H₂O)₁₂]⁶⁺, which has been previously unknown in the solid state.     

Synthesis and crystal structure of a supramolecular adduct of trinuclear molybdenum oxocluster with macrocyclic cavitand cucurbit[5]uril containing the included ionic associate Na<Superscript>+</Superscript>...Cl...Na<Superscript>+</Superscript>

The compound of composition [{Mo₃O₄(H₂O)₆Cl₃}₂(Na₂Cl⊂ C₃₀H₃₀N ₂₀O₁₀)]Cl₃⋅14H₂O (1) was prepared by evaporation of a hydrochloric acid solution containing NaCl, the trinuclear aqua complex [Mo₃O₄(H₂O)₉]⁴⁺, and the macrocyclic cavitand cucurbit[5]uril (C₃₀H₃₀N₂₀O₁₀). X-ray diffraction analysis demonstrated that the cucurbit[5]uril molecule is closed on both sides by the cluster cations through hydrogen bonding between the CO groups of the cucurbit[5]uril portals and the aqua ligands of the oxo cluster. The inner cavity of the supramolecular adduct includes an unusual ionic associate Na⁺...Cl...Na⁺. The sodium cations are coordinated by five carbonyl oxygen atoms of each portal of the macrocycle. Compound 1 is the first structurally characterized complex, in which the macrocyclic cucurbit[5]uril ligand is directly coordinated to the alkali metal cation. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1513–1517, July, 2005.     

Three rare heteromultinuclear 3d-4f salamo-like complexes constructed from auxiliary ligand 4,4′-bipy: Syntheses,structural characterizations,fluorescence and antimicobial properties

Three rare heteromultinuclear complexes, _∞[NiL(4,4′-bipy)Pr (NO₃)₃]·(CH₃)₂CHOH ( 1 ), [{CuLSm (NO₃)₃}₂(4,4′-bipy)]·CH₃OH ( 2 ) and [{CuL (CH₃CH₂OH)Eu (NO₃)₃] ( 3 ) with a symmetrical salamo-like hexadentate ligand H₂L have been synthesized, and characterized by FT-IR, UV–vis and X-ray crystallography. Complex 1 is a 1D coordination polymer constructed from heterobimetallic [Ni(L)Pr (NO₃)₃] units which are connected by the exo-dentate ligand 4,4′-bipy bearing nitrogen-donor atoms. Complex 2 is a heterotetranuclear dimer based on [Cu(L)Sm (NO₃)₃] moieties which are linked through the exo-dentate 4,4′-bipy hasing nitrogen-donor atoms. Complex 3 is a heterodinuclear structure, Cu (II) atom is five-coordinate possessing a distorted square pyramidal geometry, and Eu (III) atom is a deca-coordinate adopting a distorted bicapped square antiprism. In addition, fluorescence and antimicobial properties of the ligand H₂L and its complexes 1 – 3 have also been discussed.     

Synthesis and crystal structure of [Na2(μ-H2O)(H2O)CB[5]]Cl2 · 6H2O, [Na3(μ-H2O)4(H2O)4(CNPy@CB[6])]Cl3 · 8H2O, and [Rb2(μ-H2O)2(CNPy@CB[6])]Cl · 8H2O

The chain coordination polymers [Na₂(μ-H₂O)(H₂O)CB[5]]Cl₂ · 6H₂O (I), [Na₃(μ-H₂O)₄(H₂O)₄(CNPy@CB[6])]Cl₃ · 8H₂O (II), and [Rb₂(μ-H₂O)₂(CNPy@CB[6])]Cl₂ · 8H₂O (III) were prepared by heating (110°C) of a mixture of sodium or rubidium chloride, cucurbit[n]uril (CB[n], where n = 5, 6), 4-cyanopyridine, and water. According to X-ray diffraction data, binding of polynuclear cations with CB[n] in I–III occurs through coordination of the oxygen atoms of the cucurbit[n]uril portals to alkali metal atoms. Complexes I–III of the above composition isolated to the solid phase as supramolecular compounds with CB[n] were structurally characterized for the first time.     

Sandwich-type tetranuclear lanthanide complexes with cucurbit[6]uril: from molecular compounds to coordination polymers

Sandwich-type lanthanide complexes with macrocyclic ligand cucurbit[6]uril (C 36H 36N 24O 12, CB[6]) were synthesized under hydrothermal conditions from aqueous solutions of lanthanide(III) bromides, CB[6], and 4-cyanopyridine. According to X-ray analysis (Ln = La, Pr, Dy, Ho, Er, and Yb), the compounds with different structural types of lanthanide cores have a common fragment where the tetranuclear hydroxo complex is sandwiched between two macrocycles {(IN@CB[6])Ln 4(mu 3-OH) 4(IN@CB[6])} (6+) (IN = isonicotinate). The photoluminescence (for Ln = Eu) and Fourier transform ion cyclotron resonance mass spectra (for Ln = Pr, Dy, and Er) were studied. The compounds are used for the first time as precursors for the synthesis of lanthanide-silver heterometallic coordination polymers. The chainlike crystal structure of polymers (Ln = La, Pr, and Dy) is constituted by the sandwich complexes linked via the coordination of IN nitrogen atoms to the silver atoms.     

Synthesis and Crystal Structure of Macrocyclic Cavitand Cucurbit[5]uril and Its Supramolecular Adduct with Cu（Ⅱ）

The first supramolecular adduct (H₃O)₂[Cu(H₂O)₄](SO₄)₂·2(C₃₀H₃₀N₂₀O₁₀)·₂₄(H₂O) based on cucurbit[5]uril was synthesized and characterized by single crystal X‐ray diffraction analysis. In the adduct, copper ion is coordinated by four oxygen atoms from H₂O. The latter links two cucurbit[5]uril molecules due to a complicated hydrogen bonding containing lattice water molecules.     

Metal ion-assisted assembly of one-dimensional polyrotaxanes incorporating cucurbit[6]uril

Three cucurbit[6]uril (CB[6])-based polyrotaxanes [Cu(H₂ C6N4)(CB[6])]Cl₄·12H₂O (1), [Co(H₂ C6N4)(CB[6])]Cl₄·14H₂O (2) and [Ag(C6N4)(CB[6])]NO₃·7H₂O (3) are prepared using N,N′-bis(4-pyridylmethyl)-1,6-hexanediamine (C6N4) threading into CB[6]'s and metal ions' assistance. Single-crystal X-ray diffraction analyses reveal that polyrotaxanes 1, 2 and 3 all have 1D chain structure where 1 and 2 are linear and 3 has two shapes, linear and sawtooth, respectively. The effects of guest molecules, metal and counter ions as well as intermolecular weak interactions on the architectures of polyrotaxanes are discussed.     

3-D Hydrogen-bonded networks of metal complexes with chelidamic acid and 1,10-phenanthroline: syntheses,structures, and optical properties

The title complexes, (C₁₂H₈N₂) ? [La(C₇H₃NO₅)(C₇H₄NO₅) ? 3H₂O] ? 1.75H₂O (1), (C₁₂H₈N₂) ? [Pr(C₇H₃NO₅)(C₇H₄NO₅) ? 3H₂O] ? 2H₂O (2), (C₁₂H₈N₂)[Nd(C₇H₃NO₅)(C₇H₄NO₅) ? 3H₂O] ? 2.25H₂O (3), and (C₁₂H₈N₂) ? [Fe(C₇H₃NO₅)(C₇H₄NO₅)] ? 2H₂O (4), were synthesized and characterized by single-crystal X-ray diffraction. The crystal structures of 1–3 reveal that they are isomorphous, among which the metal atoms are all nine-coordinate with distorted tricapped trigonal prismatic coordination geometries. The Fe is six-coordinate with a distorted octahedron by two chelidamic acid ligands in 4. Complexes 1–4 are formed into 3-D networks by H-bonds and π–π stacking interactions. The fluorescence spectra of 1–3 were investigated and all exhibit strong luminescence.     

Adducts of aqua complexes of Ln3+ with a symmetrical octamethyl-substituted cucurbituril: potential applications for isolation of heavier lanthanides

Interaction of a series of lanthanide cations (Ln³⁺) with a symmetrical octamethyl-substituted cucurbituril (OMeQ[6]) has been investigated. X-ray single-crystal diffraction analysis has revealed that the interaction results in the formation of adducts of OMeQ[6] with aqua complexes of lanthanide cations ([Ln(H₂O)₈]³⁺), Ln = Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb in OMeQ[6]–Ln(NO₃)₃–H₂O systems. However, no solid crystals were obtained from systems containing La, Ce, Pr, Nd and Sm. X-ray diffraction analysis has revealed that although the solid adducts fall into two isomorphous groups, there are no significant differences in the interactions between OMeQ[6] and [Ln(H₂O)₈]³⁺ complexes and in the corresponding supramolecular assemblies. Thermodynamic parameters for the interaction between OMeQ[6] and [Ln(H₂O)₈]³⁺ complexes based on isothermal titration calorimetry experiments show two periods corresponding to the above two systems, with the lighter lanthanide cations preferring to remain in solution and the heavier lanthanide cations forming crystalline solids. Electron spectroscopy has shown that interaction of OMeQ[6] with lanthanide cations could provide a means of isolating heavier lanthanide cations from their lighter counterparts.     

Lanthanoid metal nitrates with hydrogen bonded hexamethylenetetramine

Cerium, praseodymium, and neodymium nitrate complexes with hydrogen bonded hexamethylenetetramine (HMTA) of the formula [Ce(NO₃)₂(H₂O)₅](HMTA)₂(NO₃)(H₂O)₃, [Pr(NO₃)₂(H₂O)₆]₂[Pr(H₂O)₉](HMTA)₆(NO₃)₆(H₂O)₄ and [Nd(NO₃)₂(H₂O)₅](HMTA)₂(NO₃)(H₂O)₃ have been prepared and characterized by X-ray crystallography. All the complexes belong to monoclinic crystal system. Ce and Nd complexes have P21/n space group, whereas Pr complex has C2/c. Thermal analyses of these complexes were carried out using TG, DSC, which showed their multi-step decomposition. Kinetics of thermolysis has been done by applying model fitting as well as model free isoconversional method. In order to see the response of rapid heating, ignition delay measurements were carried out. The thermal decomposition pathways have also been demonstrated. On the basis of thermal studies the thermal stability of the complexes was found in the order; Pr > Ce > Nd. In order to identify the end products of thermolyses, X-ray diffraction patterns of end product were carried out which showed the formation of corresponding metal oxides.