Theoretical and experimental study of fullerenol molecules and ions C60(OH)24 ? n(OL)n and C60(OH)24 ? n(OL)nL+ successively substituted by Alkali Metal atoms L (n = 1?24)

The equilibrium geometric parameters and the energetic characteristics of fullerenol molecules and ions C₆₀(OH)_{24 − n} (OL) _n and C₆₀(OH)_{24 − n} (OL) _n L⁺ successively substituted by alkali metal atoms L with the number of substitutions n = 1–24 have been calculated by the density functional theory B3LYP/6-31G* method. For all compounds, the structure of the covalent [C₆₀O₂₄] cage in which the oxygen atoms are bound to the C atoms of the six-membered [C₆] rings of the fullerene cage, six O atoms per [C₆] ring. The lithium derivatives have been considered in most detail. Computations have shown that the first four single substitutions of Li for H in the OH groups attached to the same C₆ ring require very low energy inputs, no more than 1 kcal/mol, and can spontaneously occur under common conditions. The further fifth and sixth single substitutions in the same C₆ ring are endothermic, but the required energy inputs are also modest (on the order of few kcal/mol). The first and second cooperative substitutions of Li for H simultaneously in all four hydroxylated C₆ rings require energy inputs of ∼3 and 11.6 kcal/mol, respectively; in the third and fourth fourfold substitutions, the energies increase by ∼15–16 kcal/mol. The mean partial energy per single substitution of Li for H in this series (n = 1−6) is ∼2 kcal/mol. Calculations have predicted that all C₆₀(OH)_{24 − n} (OLi) _n molecules with intermediated degrees of substitution (n = 1−16) can be obtained under the conditions of relatively low energy inputs (for example, under the conditions of the MALDI experiment) and can exist in the isolated state. For the sodium- and potassium-substituted analogues, the qualitative pattern persists, but the H/Na and H/K substitutions are somewhat more endothermic. The computational results are compared with the MALDI mass spectrum of the [C₆₀(OH) _x (ONa) _y -CH₃COONa) system.     

Laser flash photolysis of fullerols of C60 and of C70 in aqueous solutions

Fullerols of C₆₀ and of C₇₀ [C₆₀(OH)_n, C₇₀(OH)_m], water-soluble fullerene derivatives, unlike some other fullerene derivatives (such as C₆₀ (C₄H₆O), C₆₀ (C₃H₇N) and C₆₀ [C(COOEt)₂]_x), do not result in excited triplet state but in ionization via monophotonic process in aqueous solutions with 248 nm laser. The quantum yields of formation of hydrated electron (Φ_e ⁻) are determined to be 0.08 and 0.11 for fullerols of C₆₀ and of C₇₀ respectively at room temperature (ca. 15°C) with KI solution used as reference. By laser flash photolysis and oxidation of sulfate radical anion SO₄ ⁻, the fullerol radical cation or neutral radical of C₆₀ is confirmed to be existent and the transient absorption spectra of fullerol radical cation of C₇₀ are observed for the first time. Project supported by the National Natural Science Foundation of China     

Metallofullerenol Inhibits Cellular Iron Uptake by Inducing Transferrin Tetramerization

Herein, A549 tumor cell proliferation was confirmed to be positively dependent on the concentration of Fe³⁺ or transferrin (Tf). Gd@C₈₂(OH)₂₂ or C₆₀(OH)₂₂ effectively inhibited the iron uptake and the subsequent proliferation of A549 cells. The conformational changes of Tf mixed with FeCl₃, GdCl₃, C₆₀(OH)₂₂ or Gd@C₈₂(OH)₂₂ were obtained by SAXS. The results demonstrate that Tf homodimers can be decomposed into monomers in the presence of FeCl₃, GdCl₃ or C₆₀(OH)₂₂, but associated into tetramers in the presence of Gd@C₈₂(OH)₂₂. The larger change of SAXS shapes between Tf+C₆₀(OH)₂₂ and Tf+FeCl₃ implies that C₆₀(OH)₂₂ is bound to Tf, blocking the iron‐binding site. The larger deviation of the SAXS shape from a possible crystal structure of Tf tetramer implies that Gd@C₈₂(OH)₂₂ is bound to the Tf tetramer, thus disturbing iron transport. This study well explains the inhibition mechanism of Gd@C₈₂(OH)₂₂ and C₆₀(OH)₂₂ on the iron uptake and the proliferation of A549 tumor cells and highlights the specific interactions of a nanomedicine with the target biomolecules in cancer therapy.     

Polymer‐assisted biocatalysis: Unprecedented enzymatic oxidation of fullerene in aqueous medium

Enzymatic complexes, constructed by linear‐dendritic copolymers and laccase, are used for the unprecedented one‐pot biotransformation of fullerene (C₆₀) into epoxide‐ and hydroxyl‐derivatives under mild and environmentally friendly reaction conditions (45 °C and aqueous medium). The reaction is catalyzed by mediator pairs ‐ N‐hydroxy‐5‐norbornene‐2,3‐dicarboxylic acid imide/1‐Hydroxybenzotriazole or 2,2′‐Azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid)/1‐Hydroxybenzotriazole used in equimolar amounts. After 24 and 48 h, the biotransformation products ? C₆₀O_n, C₆₀(OH)_n, C₆₀(H)_n(OH)_n, and/or C₆₀O_n(H)_m(OH)_m range between 50 and 78%, respectively. Their structure is revealed by FTIR, NMR, and mass‐spectrometry. The mechanism of the process is discussed and elucidated. The reaction procedure allows the repeated usage of the enzyme/linear‐dendritic complex, which retains its catalytic activity after several cycles. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Fullerene complexes with divalent metal dithiocarbamates: structures,magnetic properties,and photoconductivity

A series of complexes of fullerenes C₆₀ and C₇₀ with metal dithiocarbamates {M^II(R₂dtc)₂}·C_m (m = 60 or 70) and metal dithiocarbamates coordinated to nitrogen-containing ligands (L), {M^II(R₂dtc)₂)_x·L}·C₆₀ (x = 1 or 2), where M = Cu, Zn, Cd, Hg, Mn, or Fe, R = Me, Et, Prⁿ, Prⁱ, or Buⁿ, L is 1,4-diazabicyclo[2.2.2]octane (DABCO), N,N′-dimethylpiperazine, or hexamethylenetetramine, were synthesized. The shape of dithiocarbamate molecules is sterically compatible with the spherical shape of C₆₀, resulting in an efficient interaction between their π systems. The resulting compounds are characterized by a layered or three-dimensional packing of the fullerene molecules. In the C₆₀ complexes, iron(II) and manganese(II) dithiocarbamates exist in the high-spin states (S = 2 and 5/2). The magnetic susceptibility of {M^II(Et₂dtc)₂}₂·C_m (M = Fe or Mn, m = 60 or 70) in the temperature range of 200–300 K is described by the Curie-Weiss law with Θ = −250 and −96 K and with maxima at 110 and 46 K, respectively, which is indicative of a strong antiferromagnetic spin coupling between M^II. The Weiss constants for the [{M^II(Et₂dtc)₂}₂·DABCO]·C₆₀·(DABCO)₂ complexes (M = Fe or Mn) are 1.7 and 0.3 K, respectively. The magnetic moments of the complexes containing Fe and Mn dithiocarbamates slightly increase at temperatures below 50 and 35 K, respectively, which is evidence of the ferromagnetic spin coupling between M^II in {M^II(Et₂dtc)₂}₂·DABCO. Single crystals of the complexes exhibit low dark conductivity (10⁻¹⁰–10⁻¹¹ S cm⁻¹). The visible light irradiation of these crystals leads to an increase in the photocurrent by two–three orders of magnitude. The photogeneration of free charge carriers in the complexes occurs both due to the photoexcitation of metal dithiocarbamate (Cu^II(Et₂dtc)₂) and through the charge transfer from metal dithiocarbamate (M^II(Et₂dtc)₂, M = Zn or Cd) to C₆₀. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2072–2087, November, 2007.     

Electron impact ionization of ethylene–methanol heteroclusters: Stable configurations and mechanisms in intracluster ion–molecule reactions

Reactions that proceed within mixed ethylene–methanol cluster ions were studied using an electron impact time-of-flight mass spectrometer. The ion abundance ratio, [(C₂H₄)_n(CH₃OH)_mH⁺]/[(C₂H₄)_n(CH₃OH)_m⁺], shows a propensity to increase as the ethylene/methanol mixing ratio increases, indicating that the proton is preferentially bound to a methanol molecule in the heterocluster ions. The results from isotope-labelling experiments indicate that the effective formation of a protonated heterocluster is responsible for ethylene molecules in the clusters. The observed (C₂H₄)_n(CH₃OH)_m⁺ and (C₂H₄)_n(CH₃OH)_m–1CH₃O⁺ ions are interpreted as a consequence of the ion–neutral complex and intracluster ion–molecule reaction, respectively. Experimental evidence for the stable configurations of heterocluster species is found from the distinct abundance distributions of these ions and also from the observation of fragment peaks in the mass spectra. Investigations on the relative cluster ion distribution under various conditions suggest that (C₂H₄)_n(CH₃OH)_mH⁺ ions with n + m ≤ 3 have particularly stable structures. The result is understood on the basis of ion–molecule condensation reactions, leading to the formation of fragment ions, $ {\rm CH}_2=\!=\mathop {\rm O}\limits^ + {\rm CH}_3 $ and (CH₃OH)H₃O⁺, and the effective stabilization by a polar molecule. The reaction energies of proposed mechanisms are presented for (C₂H₄)_n(CH₃OH)_mH⁺(n + m ≤ 3) using semi-empirical molecular orbital calculations.     

Endohedral chemical shifts in higher fullerenes with 72–86 carbon atoms

For all isolated pentagon isomers of the fullerenes C₆₀–C₈₆ with nonzero HOMO–LUMO gap and for one nonclassical C₇₂ isomer (C_{2 v} ), endohedral chemical shifts have been computed at the GIAO-SCF/3-21G level using B3LYP/6-31G* optimized structures. The experimental ³He NMR signals are reproduced reasonably well in cases where assignments are unambiguous (e.g. C₆₀, C₇₀ and C₇₆). On the basis of the calculated thermodynamic stability order and the comparison between the computed and experimental ³He chemical shifts, the assignments of the observed ³He NMR spectra are discussed for all higher fullerenes, and new assignments are proposed for one C₈₂ and one C₈₆ isomer (C₈₂:3 and C₈₆:17). The calculated helium chemical shifts also suggest the reassignment of the δ(³He) resonances of two C₇₈ isomers. Received: 26 March 2001 / Accepted: 10 May 2001 / Published online: 11 October 2001     

Generation of fullerenyl radicals and chemiluminescence in the (C<Subscript>60</Subscript>—R<Subscript>3</Subscript>Al)—O<Subscript>2</Subscript> system

Fullerenyl radicals (FR) RC₆₀ ^· and chemiluminescence (CL) are generated in the presence of O₂ in C₆₀—R₃Al (R = Et, Buⁱ) solutions in toluene (T = 298 K). The FR are formed due to the addition of the R^· radical, which is an intermediate of R₃Al autooxidation, to C₆₀. Mass spectroscopy and HPLC were used to identify Et_nC₆₀H_m (n, m = 1–6), Et_pC₆₀ (p = 2–6), and dimer EtC₆₀C₆₀Et as stable products of FR transformations. As found by ESR, the EtC₆₀ ^· radical (g = 2.0037) is also generated by photolysis of solutions obtained after interaction in the (C₆₀— R₃Al)—O₂ system. In the presence of dioxygen, the FR is not oxidized but yields complexes with O₂, which appear as broadening of the ESR signals. Chemiluminescence arising in the (C₆₀—R₃Al)—O₂ system is much brighter (I _max = 1.86·10⁸ photon s⁻¹ mL⁻¹) than the known background CL (I _max = 6.0·10⁶ photon s⁻¹ mL⁻¹) for the autooxidation of R₃Al and is localized in a longer-wavelength spectral region (λ_max = 617 and 664 nm). This CL is generated as a result of energy transfer from the primary emitter ³CH₃CHO* to the products of FR transformation: R_nC₆₀H_m, R_pC₆₀, and EtC₆₀C₆₀Et. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 205–213, February, 2007.     

Low-temperature thermodynamic properties of <Emphasis Type="Italic">L</Emphasis>-cysteine

Heat capacity C _p(T) of the orthorhombic polymorph of L-cysteine was measured in the temperature range 6–300 K by adiabatic calorimetry; thermodynamic functions were calculated based on these measurements. At 298.15 K the values of heat capacity, C _p; entropy, S _m⁰(T)-S _m⁰(0); difference in the enthalpy, H _m⁰(T)-H _m⁰(0), are equal, respectively, to 144.6±0.3 J K⁻¹ mol⁻¹, 169.0±0.4 J K⁻¹ mol⁻¹ and 24960±50 J mol⁻¹. An anomaly of heat capacity near 70 K was registered as a small, 3–5% height, diffuse ‘jump’ accompanied by the substantial increase in the thermal relaxation time. The shape of the anomaly is sensitive to thermal pre-history of the sample.     

Synthesis and Pyrolysis of Fullerenol-stabilized Pt Nanocolloids as a unique Approach to Pt-doped Carbon

An aqueous colloidal dispersion of Pt nanoparticles (NPs) stabilized by fullerenol C₆₀(OH)₁₂ (Pt:C₆₀(OH)₁₂) was successfully synthesized via liquid-phase chemical reduction. The subsequent pyrolysis of Pt:C₆₀(OH)₁₂ at different temperatures was conducted to afford Pt-doped carbon with different chemical compositions (Pt:C60ⁿ). X-ray absorption spectroscopy (XAS) and Infrared (IR) absorption spectroscopy and thermogravimetric measurements revealed that the thus-prepared nanocomposite consists of Pt NPs and high valent Pt-C₆₀(OH)₁₂ complex. One distinct feature of C₆₀(OH)₁₂ matrix as catalyst support is the suppression of size growth of Pt NPs during the pyrolysis up to 300 °C. Electrochemical experiments using cyclic voltammetry (CV) and linear sweep voltammetry (LSV) were performed to find that Pt:C60³⁰⁰ (pyrolyzed at 300 °C) exhibited higher activity than others, that was attributed to the π-extended feature of the as-obtained carbon.     

Theoretical study of C60(OH)20 and C60(OH)18 fullerenols and B12(OH) 12 2? , Si20O30(OH)20, and Ti20O30(OH)20 polyhydroxyl clusters and their Li-substituted derivatives

The equilibrium geometric parameters and the energetic characteristics of fullerenol molecules C₆₀(OH)₂₀ and C₆₀(OH)₁₈ and fullerenol-like inorganic clusters B₁₂(OH) ₁₂ ^2? , Si₂₀O₃₀(OH)₂₀, and Ti₂₀O₃₀(OH)₂₀ and their derivatives C₆₀(OH)_{20 ? n} (OLi) _n , C₆₀(OH)_{18 ? n} (OLi) _n , B₁₂(OH)_{12 ? n} (OLi) _n ^2? , Si₂₀O₃₀(OH)_{20 ? n} (OLi) _n , and Ti₂₀O₃₀(OH)_{20 ? n} (OLi) _n , in which the H atoms of all or one-half of hydroxyl groups are replaced by Li atoms, have been calculated by the density functional theory B3LYP/6-31G* method. It has been found that partial energies ??E(H/Li) per single substitution of Li for H in the reactions C₆₀(OH)₂₀ + nLiAc ?? C₆₀(OH)_{20 ? n} (OLi) _n + nHAc and C₆₀(OH)₁₈ + nLiAc ?? C₆₀(OH)_{18 ? n} (OLi) _n + nHAc (Ac is acetate) and the energies averaged over the entire series of changes in n, as well as over its first and second halves, do not exceed a few kilocalories per mole. It has been predicted that at least one-half (or more than one-half) of OH groups can be replaced by OLi without noticeable changes in energy; however, with a further increase in n, substitutions become endothermic and require ever-increasing energy inputs. In the completely hydroxylated closo-dodecaborane dianion with an icosahedral [B₁₂] cage and more polar B-O-H bonds, analogous H/Li substitutions are slightly exothermic so that the reaction can proceed somewhat smoother and further (toward larger n values) than in fullerenols, other conditions being the same. In the inorganic clusters Si₂₀O₃₀(OH)₂₀ and Ti₂₀O₃₀(OH)₂₀ with the [Si₂₀] and [Ti₂₀] cages, respectively, and with even more polar Si-O-H and Ti-O-H moieties, the substitutions are even more exothermic (their partial energies ??E(H/Li) increase to 4?C6 kcal/mol). For sodium and potassium analogues, the qualitative pattern persists, but H/Na and H/K substitutions are somewhat less exothermic than the H/Li substitutions. The results are compared to the data of previous calculations of stepwise H/Li and H/Na substitutions in the reactions C60(OH)24 + nLAc ?? C60(OH)_{24 ? n} (OL) _n + nHAc (L = Li, Na).     

Simulation of molecular and electronic structure of η5-π-complexes of fullereneI h -C 60 with half-sandwich XCp species (X=Si, Ge, Sn)

The molecular and electronic structure of hypothetical complexes of unsubstituted fullerene C₆₀ withI _h symmetry and its cyclopentadienyl type derivatives were simulated by the MNDO/PM3 method taking the C₆₀(XC[) _n molecules (n=1, 2, 10, 12; X=Si, Ge, Sn) and η⁵-C₆₀H₅XCp (X=Ge, Sn), respectively, as example. The complexes 12η⁵-πC₆₀(XCp)₁₂ and η⁵-πC₆₀XCp withI _h andC _5v symmetry, respectively, were found to be the most stable compounds. The energies of the X−C₆₀ bonds in these complexes are close to those of X−Cp bonds in bis(cyclopentadienyl) complexes XCp₂ and are substantially higher than the energies of similar bonds in complexes of unsubstituted fullerene η¹-πC₆₀(XCp)⁻ and η⁵-πC₆₀(XCp)⁺. Geometric parameters and spin densities in radicals C₆₀XCp and biradicals C₆₀(XCp)₂ and C₆₀H₁₀ were calculated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2155–2165, November, 1998.     

Synthesis, structural investigation, and theoretical study of pentaf luoroethyl derivatives of [60]fullerene

Pentafluoroethyl derivatives of [60]fullerene C₆₀(C₂F₅)_n (n = 6, 8, and 10) were synthesized by the reaction of C₆₀ with C₂F₅I in glass ampoules at 380–440 °C. Isomers of composition C₆₀(C₂F₅)₆ (one isomer), C₆₀(C₂F₅)₈ (five isomers), and C₆₀(C₂F₅)10 (two isomers) were isolated by chromatographic separation. Their molecular structures were established by X-ray diffraction. The relative stabilities of isomers were compared by density functional theory calculations. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 881–887, May, 2007.     

Synthesis of [<Superscript>14</Superscript>C] quincetone

Summary The water-soluble fullerene derivative C₆₀(OH)_x was radiolabeled with ⁶⁷GaCl₃. The labeling yields were determined by radio-PLC. The effects of pH, reaction time, temperature and the amount of C₆₀(OH)_x on the labeling yields were studied. The stability of ⁶⁷Ga-C₆₀(OH)_x was also examined. The results showed that the labeling yields could reach 97% under the best labeling conditions and the radiochemical purity of ⁶⁷Ga-C₆₀(OH)_x solution kept at 37 °C remained at 88% after 212 hours. The biodistribution studies of ⁶⁷Ga-C₆₀(OH)_x in mice showed a high localization of ⁶⁷Ga-C₆₀(OH)_x in the bone marrow, bone, liver and spleen with slow clearance and a negligible accumulation in the blood. These data suggest that the water-soluble C₆₀(OH)_x, having the same properties as microcolloids, may be used as a carrier of drug system for lymphatic targeting.     

Role of CH, CH3, and OH Radicals in Organic Compound Decomposition by Water Plasmas

Decomposition of acetone, methanol, ethanol, and glycerine by water plasmas at atmospheric pressure has been investigated using a direct current discharge. At torch powers of 910–1,050 W and organic compound concentrations of 1–10 mol%, the decomposition rate of methanol and glycerine was over 99%, while those of acetone and ethanol was 95.4–99%. The concentrations of H₂ obtained were 60–80% in the effluent gas for any compounds by pyrolysis. Based on the experimental results, the decomposition mechanism of organic compounds in water plasmas was proposed and the roles of intermediate species such as CH, CH₃, and OH have been investigated; CH radical generated from organic compounds decomposition was easily oxidized to form CO; incomplete oxidation of CH₃ leads to C₂H₂ generation as well as soot formation; and negligible amount of soot observed from glycerine decomposition even at high concentration indicated that oxidation of CH_×(×:1–3) was enhanced by OH radical.     

HPLC separation of hydrogenated derivatives of buckminsterfullerene

Summary The effect of composition and flow rate of the mobile phase on the HPLC separation of hydrogenated buckminsterfullerene (C₆₀H_n n=2–38) was investigated on BuckySep column. Toluene was used as the basic solvent and hexane, heptane, cyclohexane, THF, acetonitrile, acetone, ethanol and 2-propanol as co-solvents. The fraction of co-solvents was varied 10–80%, and the flow rate 1–0.1 mL min⁻¹. Toluene-acetonitrile 65∶35 and toluene-acetone 50∶50 provided the best separation. Under the best conditions complete separation of C₆₀H₂ and almost complete separation of the four most abundant isomers of C₆₀H₄ were achieved. Separation of derivatives with higher hydrogen content was very poor. Presented at: Balaton Symposium on High-Performance Separation Methods, Siófok, Hungary, September 3–5, 1997     

Paper like free-standing hybrid single-walled carbon nanotubes air electrodes for zinc–air batteries

Flexible electrode architectures based on non-functionalized (P2) and functionalized (P3) single-walled carbon nanotubes (SWNTs) were fabricated via a simple vacuum filtration process. A hybrid layer of various compositions of P2- and P3-SWNTs forms free-standing membranes (~80 μm in thickness), and their electrochemical performance was evaluated as an air electrode AEP_2/P3 in zinc–air batteries. Such bifunctionalized air electrodes showed uniform surface morphology with interconnected micron-sized porous structure with high porosity (~70%). The N₂ adsorption isotherms at 77 K are of type IV with BET-specific surface areas of AE_(60/40) and AE_(80/20) to be 130.54 and 158.76 m² g⁻¹, respectively, thus facilitates high active surface area for active oxygen reduction/evolution reactions. BJH pore size distribution of AE_(60/40) and AE_(80/20) shows maximum pores with diameter <15 nm. The zigzag interlaying of the SWNTs imparts mechanical stability and flexibility in zinc–air batteries. Zinc–air batteries with optimized compositions of P2- and P3-SWNTs in air electrode AE_(60/40) had ionic conductivity ~1 × 10⁻² S cm⁻¹ and delivered higher discharge capacity ~300 mAh g⁻¹ as compared to AE_(80/20) composition. The unique properties of AE_(P2/P3) studied in this work would enable flexible air electrode architectures in future metal–air batteries.     

[C5Li5]Mgn[C5Li5] (n?=?2–8): novel sandwich complexes containing –Mg–Mg– chain

A density functional theory (DFT) investigation on novel sandwich-type D ₅ [C₅Li₅]Mg _n [C₅Li₅] (n = 2–8) complexes containing –Mg–Mg– chain has been performed in this work. The equilibrium geometries, electronic structures, vibrational frequencies, and stabilities of these complexes are researched by B3LYP and BP86 methods at 6-311+G(d) levels of theory. The Mg _n ²⁺ sandwich complexes with D ₅ symmetry are all true minima on the potential energy surface. NBO analyses for the series of complexes reveal that the Mg–Mg bond is a weak σ covalent bond. There are mainly electrostatic interactions between C₅Li₅ ⁻ ligands and Mg _n ²⁺(n = 2–8) nuclear in these complexes. The NICS and NICS_zz computed with GIAO-B3LYP/6-311+G(d) indicates that the C₅Li₅ ⁻ rings in the series of complexes are aromatic. These novel complexes turn out to be strongly thermodynamically favored in the gas phases and may be targeted in future experiments to expand the structural domain of sandwich-type complexes.     

New Complexes of Rare Earth Elements with 3-Methyladipic Acid

Rare earth element 3-methyladipates were prepared as crystalline solids with general formula Ln₂(C₇H₁₀O₄)₃⋅nH₂O, where n=6 for La, n=4 for Ce,Sm–Lu, n=5 for Pr, Nd and n=5.5 for Y. Their solubilities in water at 293 K were determined (2⋅10^–3–1.5⋅10^–4 mol dm^–3). The IR spectra of the prepared complexes suggest that the carboxylate groups are bidentate chelating. During heating the hydrated 3-methyladipates lose all crystallization water molecules in one (Ce–Lu) or two steps (Y) (except of La(III) complex which undergoes tomonohydrate) and then decompose directly to oxides (Y, Ce) or with intermediate formation of oxocarbonates Ln₂O₂CO₃ (Pr–Tb) or Ln₂O(CO₃)₂ (Gd–Lu). Only La(III) complex decomposes in four steps forming additionally unstable La₂(C₇H₁₀O₄)(CO₃)₂. This revised version was published online in August 2006 with corrections to the Cover Date.     

Synthesis and structure of bismuth(III) oxohydroxocarboxylates

The structure and thermal transformation of bismuth(III) oxohydroxocarboxylates Bi₆O₄(OH)₄(C _n H_{2n − 1}O₂)₆, where (C _n H_{2n − 1}O₂) is a carboxylate ion and n = 2 (2–9, 11), were studied by X-ray powder diffraction, thermogravimetry, IR spectroscopy, and chemical analysis. The conditions of precipitation of bismuth carboxylates from perchlorate solutions were determined. The compounds have a layered structure and undergo the same phase transformations on heating.