Das wasserfreie Lanthanacetat,La(CH3COO)3, und sein Precursor,NH4)3[La(CH3COO)6] · 1/2 H2O: Synthese,Strukturen, thermisches Verhalten

Anhydrous Lanthanum Acetate, La(CH₃COO)₃, and its Precursor, ·NH₄)₃[La(CH₃COO)₆] · 1/2 H₂O: Synthesis, Structures, Thermal Behaviour Single crystals of (NH₄)₃[La(CH₃COO)₆] · ½ H₂O are obtained by refluxing La₂O₃in (CH₃COO)₃ · 1.5 H₂O with an excess of NH₄CH₃COO in methanol. The crystal structure (trigonal, R3 , Z = 6, a = 1 365.0(3) pm, c = 2 360(1) pm, R = 0.088, R_w = 0.061 exhibits the coordination number of nine for La³⁺, which is surrounded by three chelating-type bidentate and three unidentate acetate groups. Characteristic are monomeric units of [La(CH₃COO)₆]^3? which are connected to a three-dimensional network by hydrogen bonds with the NH ions. Thermal decomposition consists of four steps with La(CH₃COO)₃, La₂(CO₃)₃ and La₂O₂CO₃ as intermediates and La₂O₃ as the final Product. Single crystals of La(CH₃COO)₃ are obtained from La₂O₃ in a melt of NH₄CH₃COO (molar ratio 1:12) in a sealed glass ampoule. The crystal structure (trigonal, R3 , Z = 18, a = 2 203.0(5) pm; c = 987.1(3) pm, R = 0.027, R_w = 0.023) shows the coordination number of ten for La³⁺. These are three-dimensionally connected by oxygen atoms of the acetate groups with two tetradentate double-bridging and one Z,Z-type-bridging bidentate acetate group.     

Cs2(H3O)Pr(CH3COO)6 und Cs2Pr(CH3COO)5: Synthese,Kristallstrukturen und Thermolyse. Über die analogen Acetate mit Lanthan bis Terbium

Cs₂(H₃O)Pr(CH₃COO)₆ and Cs₂Pr(CH₃COO)₅: Synthesis, Crystal Structures and Thermolysis. Analogous Acetates with Lanthanum through Terbium Single crystals of Cs₂(H₃O)Pr(CH₃COO)₆ are obtained as green plates from an acetic acid solution (≈50%) of Cs₂CO₃ and Pr(CH₃COO)₃ · 1,5 H₂O. The crystal structure monoclinic, Cm, Z = 2, a = 1 540.4(4), b = 691.3(2), c = 1 221.5(4) pm, β = 104.60(5)°, V_m = 379.1(2) cm³/mol, R = 0.040, R_w = 0.035 was determined from four-circle-diffractometer data. The structure consists of monomeric Pr(CH₃COO)₃ units, in which Pr³⁺ is surrounded by nine oxygen atoms. These monomers are linked together to infinite layers parallel (001) by common acetate oxygen atoms with two ?molecules”? of Cs(CH₃COO). Together with an additional acetate ion coordinated to one of the Cs⁺ ions the composition of the layers is [Cs₂Pr(CH₃COO)₆]^?. Between these layers H₃O⁺ is located for electroneutrality. Thermal decomposition of Cs₂(H₃O)Pr(CH₃COO)₆ was examined with thermoanalytical methods (TG/DTA with coupled gas analysis), Guinier-Simon technique and IR spectroscopy: beginning at 70°C the compound looses water and acetic acid. It decomposes topotactically to Cs₂Pr(CH₃COO)₅. At 270°C this acetate decomposes to Cs₂CO₃ and Pr₂O₂CO₃ which emits CO₂ at 600°C form ing Pr₂O₃or PrO_2?x Single crystals of Cs₂Pr(CH₃COO)₅ were obtained from Pr(CH₃COO)₃, in molten Cs(CH₃COO) at about 200°C. The crystal structure tetragonal, P4₃, Z = 4, a = 1 174,5(2), c = 1 480,5(3) pm, V_m = pin,307,5(1) cm³/mol, R = 0,061, R_w= 0,031 again consists of Pr(CH₃COO)₃, monomers where Pr³⁺ has 9 oxygen ligands in its first coordination sphere. They are linked together by two ”molecules“ of cesium acetate to infinite chains along [00l] around the 4, screw axis. There are also acetate bridges between these chains. Isotypic compounds Cs₂(H₃O)M(CH₃COO)₆ and Cs₂M(CH₃COO)₅, and Cs₂M(CH₃COO)₅with M = La? Tb, were obtained from acetic acid solutions or thermal decomposition and were characterized by X-ray Guinier techniques.     

Syntheses and Crystal Structures of Potassium–Lanthanoid(III) Complexes with the 1,2‐Benzenedisulfonate Ligand

The complexes [K(H₂O)₂LnL₂] (Ln = La or Nd; L = 1,2‐benzenedisulfonate) and [K(H₂O)Yb(H₂O)₄L₂] were initially isolated fortuitously from attempts to prepare the corresponding Ln₂L₃ complexes from Ln₂O₃ and H₂L in water. Indeed the bulk products from these reactions have the composition Ln₂L₃. Subsequently, deliberate syntheses by reacting equimolar amounts of Ln₂L₃ with K₂L in water gave the complexes in good yield. X‐ray crystal structures of [K(H₂O)₂LnL₂] (Ln = La or Nd) showed the complexes to be isostructural with a two dimensional polymeric network structure in which LnL₂ units are linked into chains crosslinked by potassium ions. Each Ln is nine coordinate with solely sulfonate oxygen donor atoms. Between adjacent lanthanoid ions there are three different types of sulfonate bridges and two examples of each. Most noteworthy is highly unsymmetrical bridging through μ‐η²‐sulfonate oxygen atoms. Consequently, one Ln–O bond is ca. 0.5 Å longer than the other eight. Potassium is nine‐coordinate with seven sulfonate oxygen atoms and two aqua ligands, and surprisingly <K–O(sulfonate)> is much longer than <K–O(H₂O)>. Pairs of potassium ions are linked by two μ‐η²‐sulfonate oxygen atoms, which are unsymmetrically bridging. The structure of [K(H₂O)Yb(H₂O)₄L₂] comprises discrete tetranuclear units containing two independent ytterbium ions, each coordinated by four water molecules and two chelating (via seven membered rings) disulfonate ligands, and two potassium ions, each coordinated by six sulfonate oxygen atoms and a water molecule. For each potassium, four of the coordinated sulfonate oxygen atoms are from sulfonate ligands bonded to one ytterbium atom and two from sulfonate ligands attached to the other ytterbium atom. In contrast to the Nd and La complexes, <K–O(sulfonate)> is shorter than <K–O(H₂O)>.     

pH Dependent Synthesis of NdIII Coordination Compounds Based on Bifunctional 5‐(4‐Pyridyl)tetrazole‐2‐acetic Acid

The Nd^III coordination compounds [Nd(4‐pytza)₃(H₂O)₂] · 2H₂O ( 1 ) and [Nd(4‐pytza)₂(H₂O)₄]Cl · 2H₂O ( 2 ) [H4‐pytza = 5‐(4‐pyridyl)tetrazole‐2‐acetic acid] were synthesized by reactions of K4‐pytza and NdCl₃ · 6H₂O at different pH values. Single crystal X‐ray diffraction analysis reveals that 4‐pytza ligands in 1 in a μ_1,3‐COO syn‐syn or μ_1,1,3‐COO bridging mode coordinate to two central Nd^III atoms to display a dinuclear unit, which is connected by one of these 4‐pytza ligands acting in end‐to‐end bridging mode to form a 1D ladder‐like chain. Different from 1 , each 4‐pytza in 2 with a μ_1,3‐COO syn‐anti bridging mode coordinates to two Nd^III atoms to display a 1D zigzag chain. Furthermore, the luminescence properties of 1 and 2 were investigated at room temperature in the solid state.     

Co(C2(COO)2)(H2O)4 · 2 H2O und Co(C2(COO)2)(H2O)2: zwei Koordinationspolymere mit dem Acetylendicarboxylat‐Dianion

Co(C₂(COO)₂)(H₂O)₄ · 2 H₂O and Co(C₂(COO)₂)(H₂O)₂: Two Co‐ordination Polymers of the Acetylenedicarboxylate Dianion By reaction of CoCO₃ with an aqueous solution of acetylenedicarboxylic acid and subsequent crystallisation single‐crystals of Co(C₂(COO)₂)(H₂O)₄ · 2 H₂O were obtained (P2₁/a, Z = 2). In the solid state structure cobalt is octahedrally surrounded by four water molecules and two oxygen atoms of the carboxylate anions. These octahedra are connected to chains by the dicarboxylates. Already at ambient conditions Co(C₂(COO)₂)(H₂O)₄ · 2 H₂O looses four water molecules to give Co(C₂(COO)₂)(H₂O)₂ (isotypic to Mn[C₂(COO)₂] · 2 H₂O, C2/c, Z = 4). The cobalt cation is now octahedrally co‐ordinated by two water molecules and four oxygen atoms of the dicarboxylate ligands, which connect the Co octahedra to a three dimensional network. Thermoanalytical investigations show another mass loss at about 200 °C, which leads to non‐crystalline products. Measurements of the magnetic susceptibilities result in the expected behaviour for Co²⁺ in an octahedral co‐ordination (high spin, ⁴T₁ ground state). The effective magnetic moment at room temperature is n_eff = 5.51 μ_B.     

A Novel One‐Dimensional Copper Mellitate Complex Featured by {Cu(H2O)2(urea)[C6(COO)4(COOH)2]}n2n– Polyanions

Blue monoclinic single crystals of the novel one‐dimensional [H₃N‐(CH₂)₆‐NH₃][Cu(H₂O)₂(urea)(μ₂‐C₆(COO)₄(COOH)₂)] · H₂O coordination polymer were prepared in aqueous solution at room temperature in the presence of 1,6‐diaminohexane and urea [space group P2₁/n (no. 14) with a = 958.48(9), b = 1465.74(11), c = 1821.14(12) pm, β = 97.655(8)°]. The Cu²⁺ cation is coordinated in a square pyramidal manner by two oxygen atoms stemming from the dihydrogen mellitate tetraanion, one oxygen atom from the urea molecule, and two water molecules. The Cu–O distances are in the range of 193.3(2) and 229.4(2) pm. The connection between Cu²⁺ and [C₆(COO)₄(COOH)₂]^4– yields infinite chain‐like polyanions parallel to [1$\bar{}$ 01] with a composition of {Cu(H₂O)₂(urea)[C₆(COO)₄(COOH)₂]}_n^2n–. The dihydrogen mellitate tetraanion adopts a μ₂ coordination mode. The [(H₃N–(CH₂)₆–NH₃)]²⁺ cations are accommodated between the chains as counter cations. The hexane‐1,6‐diammonium cations adopt a partial synclinal conformation. The chains are connected by strong and weak hydrogen bonds. Magnetic measurements reveal a paramagnetic Curie‐Weiss behavior and a magnetic moment of 1.93 μ_B per Cu²⁺. Thermoanalytical investigations in air show that the complex is stable up to 135 °C, and the following decomposition processes yield CuO.     

KEu(CH3COO)3, das erste ternäre Europium(II)-acetat

KEu(CH₃COO)₃, the First Ternary Europium(II) Acetate On of EuCl₂ with a melt of dry potassium acetate yields pale greenish-yellow single crystals (300°C, sealed glass ampoule, EuCl₂ and K(CH₃COO) in a molar ratio of 1 : 3). The crystal structure determination (orthorhombic, P2₁2₁2₁ (no. 19), Z = 8, a = 1166.3(1) pm, b = 1288.4(2) pm, c = 1493.9(2) pm, R = 0.043, R_w = 0.032) revealed the composition KEu(CH₃COO)₃. The structure consists of one-dimensional chains built up by bridging acetate groups in the [100] and [001] directions in which potassium and europium alternate as central atoms. Eu²⁺ is surrounded by nine and eight and K⁺ by seven and six oxygen atoms, respectively. These chains are linked in the [010] direction so that a three-dimensional network is formed. The high coordination numbers of the acetate oxygen atoms of up to four are remarkable. Therefore, the acetate groups have highly bridging functions in addition to their chelating coordination of the cations.     

Cu(II) and Pd(II) complexes of N-(2-hydroxybenzyl)aminopyridines

N-(2-Hydroxybenzyl)aminopyridines (Lⁱ) react with Cu(II) and Pd(II) ions to form complexes in the compositions Cu(Lⁱ)₂(CH₃COO)₂ · nH₂O (n = 0, 2, 4), Pd(Lⁱ)₂Cl₂ · nC₂H₅OH (n = 0, 2) and Pd(L²)₂Cl₂ · 2H₂O. In the complexes, the ligands are neutral and monodentate which coordinate through pyridinic nitrogen. Crystal data of the complexes obtained from 2-amino pyridine derivative have pointed such a coordinating route and comparison of the spectral data suggests the validity of similar complexation modes of other analog ligands. Cu(II) complex of N-(2-hydroxybenzyl)-2-aminopyridine (L¹), [Cu(L¹)₂(CH₃COO)₂] has slightly distorted square planar cis-mononuclear structure which is built by two oxygen atoms of two monodentate carboxylic groups disposed in cis-position and two nitrogen atoms of two pyridine rings. The remaining two oxygen atoms of two carboxylic groups form two Cu and H bridges containing cycles which joint at same four coordinated copper(II) ion. IR and electronic spectral data and the magnetic moments as well as the thermogravimetric analyses also specify on mononuclear octahedric structure of complexes [Cu(L²)₂(CH₃COO)₂ · 2H₂O] and [Cu(L³)₂(CH₃COO)₂ · 4H₂O] where L² and L³ are N-(2-hydroxybenzyl)-2- or 3-aminopyridines, respectively.     

Construction of Two High‐Nuclear 3d‐4d Heterometallic Cluster Organic Frameworks by Introducing a Bifunctional Tripodal Alcohol as a Structure‐Directing Agent

Two unique heterometallic cluster organic frameworks, [Cd₄Mn^III₄Mn^II₆(Tri)₄(CH₃COO)₁₄(μ₄‐O)₂(μ₃‐O)₂(H₂O)₂] Cd(H₂O)₂?9 H₂O ( 1 ) and Cu[Cd₅Cu₆(Tri)₄(CH₃COO)₉(H₂O)₄]₂(CH₃COO)₃?24 H₂O ( 2 ) (H₃Tri=2‐(hydroxymethyl)‐2‐(pyridine‐4‐yl)‐1,3‐propanediol), have been successfully prepared by employing a bifunctional tripodal alcohol ligand as a structure‐directing agent. Crystal structure analyses reveal that 1 represents a rare example of frameworks constructed from Cd?Mn heterometallic chains, and 2 is the first heterometallic MOF based on highest‐nuclear Cd?Cu heterometallic cluster building blocks. Furthermore, the magnetic properties and gas adsorption abilities of 1 and 2 were systematically studied.     

Synthese und Kristallstruktur von Praseodympropionat-trihydrat,Pr(CH3CH2COO)3(H2O)3

Synthesis and Crystal Structure of Praseodymium Propionate Trihydrate, Pr(CH₃CH₂COO)₃(H₂O)₃ Single crystals of Pr(CH₃CH₂COO)₃(H₂O)₃ were obtained by dissolving freshly prepared praseodymium hydroxide in diluted propionic acid. The crystal structure (monoclinic, P2₁/c, Z = 4, a = 1034.2(2) pm, b = 1521.2(3) pm, c = 2086.3(7) pm, β = 102.87(2)°, R1 = 0.0864, wR2 = 0.1196) consists of one-dimensional infinite chains parallel [010]. Pr1 and Pr2 are coordinated by four tridentate-bridging propionate groups. Additionally, Pr1 is coordinated by three “coordination water” molecules, Pr2 by two bidentate propionate groups. There are, in addition, three “crystal water” molecules so that praseodymium propionate trihydrate should be formulated as [(H₂O)₃Pr1(CH₃CH₂COO)₄Pr2(CH₃CH₂COO)₂] (H₂O)₃.     

Wasserfreie Selten-Erd-Acetate,M(CH3COO)3 (M = Sm?Lu,Y) mit Kettenstruktur. Kristallstrukturen von Lu(CH3COO)3 und Ho(CH3COO)3

Anhydrous Rare-Earth Acetates, M(CH₃COO)₃ (M = Sm? Lu, Y) with Chain Structures. Crystal Structures of Lu(CH₃COO)₃ and Ho(CH₃COO)₃ Single crystals of the anhydrous rare-earth acetates containing lutetium (type 1) and holmium (type 2) were obtained by crystallisation at 120°C from diluted acetic acid solutions of their oxides and cesium acetate. The crystal structures [Lu(CH₃COO)₃: orthorhombic, a = 825.85(8), b = 1 398.1(2), c = 823.9(1) pm, V_m = 143.24(3) cm³/mol, space group Ccm2₁ (No. 36), Z = 4, R = 0.035, R_w = 0.030; Ho(CH₃COO)₃: monoclinic, a = 1 109.1(3), b = 2 916.3(10), c = 786.8(2) pm, β = 131.90(1)°, V_m = 142.58(8) cm³/mol, space group C2/c (No. 15), Z = 8, R = 0.039, R_w = 0.039, R_w = 0.026] were determined from four-circle diffractometer data sets. The structures consist of one-dimensional infinite chains built up by bridging acetate ions. Ho³⁺ is coordinated by 8 oxygen atoms, whereas Lu³⁺ has only 7 nearest oxygen neighbours. The chains are stacked parallel to the [001] direction. Isotypic compounds with Tm? Lu (type 1) and Sm? Er, Y (type 2) were prepared as powders and characterized by X-ray powder patterns. Thermoanalytical investigations (DTA, Guinier-Simon technique) of all compounds have shown that there is a first-order phase transition at 180°C (type 2) and in the range of 230–255°C (type 1). The high-temperature phase crystallizes with the known Sc(CH₃COO)₃ structure (type 0) where the rare earth cations are surrounded by 6 oxygen atoms. In the case of the type 1 compounds the phase transition is reversible.     

M(H2O)2(4,4′‐bipy)[C6H4(COO)2]·2H2O (M = Mn2+, Co2+) – Zwei isotype Koordinationspolymere mit Schichtstruktur

M(H₂O)₂(4,4′‐bipy)[C₆H₄(COO)₂]·2H₂O (M = Mn²⁺, Co²⁺) – Two Isotypic Coordination Polymers with Layered Structure Monoclinic single crystals of Mn(H₂O)₂(4,4′‐bipy)[C₆H₄(COO)₂]·2H₂O ( 1 ) and Co(H₂O)₂(4,4′‐bipy)[C₆H₄(COO)₂]· 2H₂O ( 2 ) have been prepared in aqueous solution at 80 °C. Space group P2/n (no. 13), Z = 2; 1 : a = 769.20(10), b = 1158.80(10), c = 1075.00(10) pm, β = 92.67(2)°, V = 0.9572(2) nm³; 2 : a = 761.18(9), b = 1135.69(9), c = 1080.89(9) pm, β = 92.276(7)°, V = 0.9337(2) nm³. M²⁺ (M = Mn, Co), which is situated on a twofold crystallographic axis, is coordinated in a moderately distorted octahedral fashion by two water molecules, two oxygen atoms of the phthalate anions and two nitrogen atoms of 4,4′‐biypyridine ( 1 : M–O 219.5(2), 220.1(2) pm, M–N 225.3(2), 227.2(2) pm; 2 : Co–O 212.7(2), 213.7(2) pm, Co–N 213.5(3), 214.9(3) pm). M²⁺ and [C₆H₄(COO)₂)]^2? build up chains, which are linked by 4,4′‐biyridine molecules to yield a two‐dimensional coordination polymer with layers parallel to (001).Thermogravimetric analysis in air of 1 indicated a loss of water of crystallization between 154 and 212 °C and in 2 between 169 and 222 °C.     

Zur Darstellung und Kristallstruktur von CrSO4 · 3 H2O

Preparation and Crystal Structure of CrSO₄ · 3 H₂O Evaporating a solution of Cr²⁺ in dilute sulphuric acid at 70°C light blue crystals of CrSO₄ · 3 H₂O were grown. Its x-ray powder diffraction pattern is quite similar to that of CuSO₄ · 3 H₂O. The crystal structure refinement of CrSO₄ · 3 H₂O (space group Ce, a = 5.7056(8) Å, b = 13.211(2) Å, c = 7.485(1) Å, β = 96.73(1)°, Z = 4) from single crystal data, using the parameters of the copper compound as starting values, results in a final R-value of R = 3.8%. The surrounding of the Cr²⁺ ion can be described as a strongly elongated octahedron. The basal plane of the CrO₆-octahedron consists of three hydrate oxygen atoms and one sulphate oxygen atom. The two more distant axial oxygen atoms also belong to sulphate groups. Thus they are forming chains of alterning CrO₆-octahedra and SO₄-tetrahedra along [110] and [1–10] linked via common corners. These chains are connected via sulphate groups and by bridging hydrogen bonds to a 3-dimensional network.     

Structure of Cardocyclic Silazaoxanes

Sr₂[C₈H₈(COO)₄] · 4 H₂O – a Compound with a Three-Dimensional Framework Structure Colourless, platelett-like single crystals of Sr₂[C₈H₈(COO)₄] · 4 H₂O were grown in an aqueous silica gel. Sr₂[C₈H₈(COO)₄] · 4 H₂O is monoclinic, space group C2/c, a = 1227.1(3) pm, b = 667.8(3) pm, c = 1956.8(4), β = 102.51(2)°. X-ray structure determination (R_g = 2.19%) showed that Sr²⁺ is coordinated by three water molecules and six oxygen atoms stemming from carboxylate groups. The coordination polyhedra share common edges and form layers extending parallel to (001). The connection of these layers and [C₈H₈(COO)₄]^4? ions yields a three-dimensional frame work. Oxygen atoms of carboxylate groups bound weakly to Sr²⁺ are favoured as proton acceptors in hydrogen bonds.     

New mixed-anion zinc(II) complexes, [Zn(phen)2(CCl3COO)(H2O)](NO3) and [Zn(bpy)2(CH3COO)](ClO4) · H2O; synthesis,characterization and crystal structures

Zinc(II) complexes with 1,10-phenanthroline (phen) and 2,2′-bipyridine (bpy) containing two different anions have been synthesized and characterized by elemental analysis, IR-, ¹H?NMR-, ¹³C?NMR spectroscopy. The single crystal X-ray data of [Zn(phen)₂(CCl₃COO)(H₂O)](NO₃) show the complex to be monomeric and the Zn atom with an unsymmetrical six-coordinate geometry, coordinated by four nitrogen atoms of “phen”, one trichloroacetate and one water. The crystal structure of [Zn(bpy)₂(CH₃COO)](ClO₄)?·?H₂O shows each zinc atom chelated by the nitrogen atoms of “bpy” and also two oxygen atoms of acetate. From the infrared spectra and X-ray crystallography, it is established that coordination of the carboxylate group to zinc is different for trichloroacetate and acetate.     

Preparation and Optical Properties of Gold-Dispersed BaTiO3, PGO (Pb5Ge3O11) and PLT (Pb1-1.5xLaxTiO3) Thin Films by Sol-Gel Process

Gold-dispersed BaTiO₃, PGO and PLT thin films, which will be used for third-order nonlinear optical devices, were prepared by sol-gel process with spin-coating using HAuCl₄4H₂O, Ba(CH₃COO)₂, Ti[O(CH₂)₃CH₃]₄, Pb(CH₃COO)₂3H₂O, Ge[O-n-C₄H₉]₄, La(CH₃COO)₃1.5 H₂O as starting materials. The thin films were heat-treated in air at temperatures ranging from 400 to 800 for 1 h. The nonlinear optical property of these thin films was measured by the degenerate four-wave mixing (DFWM) method using a frequency-doubled Nd: YAG laser with 20 ps pulse duration. Third-order nonlinear susceptibility χ⁽³⁾ of gold-dispersed BaTiO₃, PGO and PLT thin films with 5 vol% of gold were 1.410⁻⁶ esu, 3.510⁻⁷ esu respectively. The large χ⁽³⁾ may be ascribed to the high dielectric constant of the films.     

Pr(CH3COO)3, ein wasserfreies Selten-Erd-Acetat mit Netzwerkstruktur

Pr(CH₃COO)₃, an Anhydrous Rare-Earth Acetate with a Network Structure Pr(CH₃COO)₃ may be prepared by dehydration of Pr(CH₃COO)₃ · 1,5 H₂O at 180°C as an amorphous green powder. Single crystals were grown from the powder by addition of (NH₄)CH₃COO as ?mineralisator”? at 180°C in a sealed glass ampoule. The crystal structure (tetragonal, P4 2₁c (no. 114), Z = 24, a = 2106.5(3), c = 1323.6(1) pm, V_m = 147.39(3) cm³/mol, R = 0.055, R_w = 0.029) was determined from four-circle-diffractometer data. The Pr³⁺ ions occupy three crystallographically independent positions and are surrounded by 9 and 10 oxygen atoms, respectively. Acetate ions connect the cations to a complicated three-dimensional network.     

Synthesis and Structure of Trinuclear Iron Acetate [Fe3O(CH3COO)6(H2O)3][AuCl4]·6H2O

Iron acetate of composition [Fe₃O(CH₃COO)₆(H₂O)₃][AuCl₄]·6H₂O (I) was synthesized and investigated by X-ray diffraction analysis and Mössbauer spectroscopy. The [Fe₃O(CH₃COO)₆(H₂O)₃]⁺ complex cation has a structure typical for ₃-O bridged trinuclear ferric compounds with iron atoms lying at the vertices of a regular triangle with an oxygen atom at the center. The iron atoms are each coordinated by 4 oxygen atoms of the four bridging carboxylic groups, the ₃-O bridging atom, and the coordinated water molecule in the trans-position to the latter. In the trinuclear cation, the Fe(III) ions are coupled by antiferromagnetic exchange interactions with the exchange parameter J = -29.0 cm ^–1 (HDVV model for D _3h symmetry). The specific role of the solvate water molecules in structure formation is discussed.     

Structure, IR and Mössbauer spectra, and magnetic properties of [Fe2CoO(CH3COO)6(3-CI-Py)3]· 1/4· 3-Cl-Py· 1/4(CH3)2CO· 1/2H2O

The structure of the hetemnuclear iron acetate [Fe₂CoO(CH₃COO)₆(3-Cl-Py)₃]·1/4· 3-Cl-y× 1/4(CH₃)₂CO· 1/2H₂O was determined by X-ray structure analysis. The crystal has a molecular structure and is monoclinic with lattice parameters a = 21.034(4). b = 8.398(2), c = 23.360(5) Å, β= 98.28(3)?, R = 0.0656. space group P2₁/c. The trinuclear complex [Fe₂CoO(CH₃COO)₆(H₂O)₃] has a structure typical for iron(III) μ₃-O compounds with iron atoms hing at the vertices of the equilateral triangle centered by an oxygen atom. The metal atoms are each coordinated to four oxygen atoms of the four bridging carboxy groups, the bridging oxygen atom (μ₃-O), and the coordinated 3-chloropyridine molecule which is trans relative to the latter atom. According to Mössbauer spectroscopy data, the iron(III) ions are in the high-spin state. The value of (μ_ef)_mole/μ₃ at room temperature and its temperature dependence suggest that the resulting magnetic exchange interaction between the paramagnetic centers of the cluster is antiferromagnetic.     

Synthesis and crystal structure of heteronuclear La( III )‐Cu(II ) complex { [LaCu2(NTA)2(4,4′‐bpy)(H2O)3]NO3·5H2O}n

A novel La( III )‐Cu( II ) heterometallic coordination polymer {[LaCu₂(NTA)₂(4,4′‐bpy)(H₂O)₃]NO₃·5H₂O]_n, where H₃NTA denotes nitrilotriacetic acid and 4,4′‐bpy denotes 4, 4‐bipyridine, was synthesized and characterized by IR spectrum, elemental analysis and X‐ray diffraction. The complex crystallizes in the triclinic space group Pi with cell parameters a = 1.33710(10) nm, b = 1,44530(10) nm, c =1.0949(2) nm, α = 71.905(7)°, β = 74.327(7)°, γ = 64.427(9)°, V = 1.7912(4) nm³and Z = 2. It consists of heterometallic units, in which each La( II ) ion is coordinated in a distorted monocapped square antiprism by three oxygen atoms from water molecules and six carboxyl oxygen atoms from five NTA^3? ions, and each Cu( I ) ion is coordinated by one nitrogen atom from 4,4′‐bpy and one nitrogen atom, three oxygen atoms from NTA^3?. In the title complex, La( I ) ions and Cu( II ) ions are connected by the heterometallic bridging of NTA^3?, constructing a two‐dimensional network structure along the [110]. And it is extended into an infinite three‐dimensional network structure by the formation of homometallic bridging of Cu‐4, 4′‐bpy‐Cu, exhibiting a certain inclusion ability.