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A new organic-inorganic hybrid [{p-(CH3)2NH—C6H4—NH3}2Cl][BiI6] was synthesized and its crystal structure was established. The hybrid consists of an inorganic anion [BiI6]3− and an organic cation [{p-(CH3)2NH-C6H4-NH3}2Cl]3+. The [BiI6]3− anions are linked via non-covalent I...I interactions between axial atoms of neighboring anions to form chains running along the c axis of the tetragonal unit cell. In the cationic part, the Cl− anion is involved in four (N)H…Cl hydrogen bonds with hydrogen atoms of the p-(CH3)2NH—C6H4—NH32+ cation, forming a two-dimensional substructure. Alternating covalent and I...I halogen bonds in the anionic substructure and cation—anion hydrogen bonds provide the formation of a three-dimensional supramolecular structure with a band gap of 1.93 eV.

A careful selection of organic and inorganic components enables the production of unusual structure types with promising practical properties by facile syntheses. In this paper, we describe novel supramolecular architectures comprising organic adamantane-like divalent building blocks and iodide or polyiodide anions. Highly acidic conditions facilitated the formation of a doubly protonated organic ligand out of 5,7-dimethyl-1,3-diazaadamantane that generates three different crystal structures with inorganic counterions. In these structures, cationic substructures are constructed by transforming neutral organic ligands into [(C10N2H20)I]+ or [(C10N2H20)(H2O)]2+ cations, which crystallize with charge-compensating iodine-based anions of different complexities. All three crystal structures are characterized by various noncovalent forces, ranging from strong (N)H⋯I, (O)H⋯I, and (N)H⋯O hydrogen bonds to secondary and weak I⋯I interactions. Raman and diffuse reflectance spectroscopy as well as DFT calculations were employed to describe the electronic structures and optical properties of new supramolecular architectures, with particular attention to the role of non-covalent interactions.

Intermetallic compounds with semiconducting properties are rare, but they give rise to advanced materials for energy conversion and saving applications. Here, we present ReGa2Ge, a new electron-pre...

This work represents an important step in the quest to make heteromultimetallic molecules featuring specific metal types and complicated metal ratios. The rational design, synthesis, and characterization of a complex heterotrimetallic single-source molecular precursor for the next generation sodium-ion battery cathode material, Na2Mn2FeO6, is described. A unique pentametallic platform [MnII(ptac)3-Na-MnIII(acac)3-Na-MnII(ptac)3] (1) was derived from the known polymeric structure of [NaMnII(acac)3]∞, through a series of elaborate design procedures, such as mixed-ligand, unsymmetric ligand, and mixed-valent approaches. Importantly, the application of those techniques results in a molecule with distinctively different transition metal positions in terms of ligand environment and oxidation states. An isovalent substitution of FeIII for the central MnIII ion forms the target heterotrimetallic precursor [MnII(ptac)3-Na-FeIII(acac)3-Na-MnII(ptac)3] (3) with an appropriate metal ratio of Na:Mn:Fe = 2:2:1. The arrangement of metal ions and ligands in this pentametallic assembly was confirmed by single crystal X-ray investigation. The unambiguous assignment of the positions and oxidation states of the Periodic Table neighbors Fe and Mn in 3 has been achieved by a combination of investigative techniques that include synchrotron resonant diffraction, X-ray multiwavelength anomalous diffraction, X-ray fluorescence spectroscopy, Mossbauer spectroscopy, and gas-phase DART mass spectrometry. The heterotrimetallic single-source precursor 3 was shown to exhibit a clean decomposition pattern yielding the phase-pure P2-Na2Mn2FeO6 quaternary oxide with high uniformity of metal ion distribution as confirmed by electron microscopy.

A known trinuclear structure was used to design the heterobimetallic mixed-valent, mixed-ligand molecule [CoII (hfac)3 -Na-CoIII (acac)3 ] (1). This was used as a template structure to develop heterotrimetallic molecules [CoII (hfac)3 -Na-FeIII (acac)3 ] (2) and [NiII (hfac)3 -Na-CoIII (acac)3 ] (3) via isovalent site-specific substitution at either of the cobalt positions. Diffraction methods, synchrotron resonant diffraction, and multiple-wavelength anomalous diffraction were applied beyond simple structural investigation to provide an unambiguous assignment of the positions and oxidation states for the periodic table neighbors in the heterometallic assemblies. Molecules of 2 and 3 are true heterotrimetallic rather than a statistical mixture of two heterobimetallic counterparts. Trinuclear platform 1 exhibits flexibility in accommodating a variety of di- and trivalent metals, which can be further utilized in the design of molecular precursors for the NaMM'O4 functional oxide materials.

Glycinium triiodide was synthesized and its crystal structure was determined. The crystal structure consists of alternating asymmetric triiodide anions characterized by Raman spectroscopy and glycinium cations. The cations and anions form dimers (GlyH)2(I3)2via (N)H···O, (N)H···I, and (O)H···I hydrogen bonds. The dimers are further linked into chains by secondary I···I interactions between adjacent triiodide anions. The supramolecular structure of glycinium triiodide is discussed in comparison with polyiodides of various cations.

The Li1.17Ni0.17Mn0.50Co0.17O2 Li-rich NMC positive electrode (cathode) for lithium-ion batteries has been coated with nanocrystals of the LiMn1.5Co0.5O4 high-voltage spinel cathode material. The coating was applied through a single-source precursor approach by a deposition of the molecular precursor LiMn1.5Co0.5(thd)5 (thd = 2,2,6,6-tetramethyl-3,5-heptanedionate) dissolved in diethyl ether, followed by thermal decomposition at 400 &deg, C inair resulting in a chemically homogeneous cubic spinel. The structure and chemical composition of the coatings, deposited on the model SiO2 spheres and Li-rich NMC crystallites, were analyzed using powder X-ray diffraction, electron diffraction, high angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), and energy-dispersive X-ray (EDX) mapping. The coated material containing 12 wt.% of spinel demonstrates a significantly improved first cycle Coulombic efficiency of 92% with a high first cycle discharge capacity of 290 mAhg&minus, 1. The coating also improves the capacity and voltage retention monitored over 25 galvanostatic charge&ndash, discharge cycles, although a complete suppression of the capacity and voltage fade is not achieved.

This work represents an important step in the quest to make hetero

The unsolvated Cu(II) complex with bis(pentafluorobenzoyl)methanide ligand (L, C6F5COCHCOC6F5−) is prepared and crystallized as [CuL2] (1) using gas phase sublimation-deposition at 150 °C. The X-ray crystallographic characterization confirmed the centrosymmetric mononuclear structure of 1 with a square planar geometry around Cu(II) (Cu–Oav 1.9149(8) A). The reaction of 1 with sodium hexafluoroacetylacetonate [Na(hfac)] in a solvent-free environment afforded [Na2Cu2L4(hfac)2] (2), the first heterometallic Na–Cu β-diketonate characterized by single-crystal X-ray diffraction. In the centrosymmetric tetranuclear structure of 2, a dimeric [Na(hfac)]2 unit is sandwiched between two CuL2 units. The L-ligands function as chelating-bridging between Cu and Na through one of their O-atoms. The hfac ligands are chelating-bridging between Cu and Na and between Na(1) and Na(1A) through both O-atoms. In addition to the five primary Na–O interactions (av. 2.4109(17) A), three secondary Na–F contacts (av. 2.6006(15) A) contribute to the overall distorted square antiprismatic coordination environment for Na. The geometry of Cu is square pyramidal with Cu–O(L) distances averaging at 1.922(14) A and Cu–O(hfac) of 2.3021(15) A. Thermal decomposition of 2 yields a mixture of NaCuF3, Na2CuF4 and NaF, when conducted at 230 °C in argon at ambient pressure.

Based on the well-established model structure of Li2M2(tbaoac)6, the first series of heterometallic molecular precursors Na2M2(tbaoac)6(THF)2 (M = Fe, Co, and Ni) have been designed and successfully utilized for the preparation of NaMO2 oxide cathode materials of sodium-ion batteries.

Design of heterotrimetallic molecules, especially those containing at least two different metals with close atomic numbers, radii, and the same coordination number/environment is a challenging task. This quest is greatly facilitated by having a heterobimetallic parent molecule that features multiple metal sites with only some of those displaying substitutional flexibility. Recently, a unique heterobimetallic complex LiMn2(thd)5 (thd = 2,2,6,6-tetramethyl-3,5-heptanedionate) has been introduced as a single-source precursor for the preparation of a popular spinel cathode material, LiMn2O4. Theoretical calculations convincingly predict that in the above trinuclear molecule only one of the Mn sites is sufficiently flexible to be substituted with another 3d transition metal. Following those predictions, two heterotrimetallic complexes, LiMn2−xCox(thd)5 (x = 1 (1a) and 0.5 (1b)), that represent full and partial substitution, respectively, of Co for Mn in the parent molecule, have been synthesized. X-ray structural elucidation clearly showed that only one transition metal position in the trinuclear molecule contains Co, while the other site remains fully occupied by Mn. A number of techniques have been employed for deciphering the structure and composition of heterotrimetallic compounds. Synchrotron resonant diffraction experiments unambiguously assigned 3d transition metal positions as well as provided a precise “site-specific Mn/Co elemental analysis” in a single crystal, even in an extremely difficult case of severely disordered structure formed by the superposition of two enantiomers. DART mass spectrometry and magnetic measurements clearly confirmed the presence of heterotrimetallic species LiMnCo(thd)5 rather than a statistical mixture of two heterobimetallic LiMn2(thd)5 and LiCo2(thd)5 molecules. Heterometallic precursors 1a and 1b were found to exhibit a clean decomposition yielding phase-pure LiMnCoO4 and LiMn1.5Co0.5O4 spinels, respectively, at the relatively low temperature of 400 °C. The latter oxide represents an important “5V spinel” cathode material for the lithium ion batteries. Transmission electron microscopy confirmed a homogeneous distribution of transition metals in quaternary oxides obtained by pyrolysis of single-source precursors.

International audience; The first example of ionic β-diketonates in which both the cation and anion are octahedral coordinatively saturated metal diketonate moieties are reported. Heterometallic tin−transition-metal heteroleptic diketonates were obtained through solid-state redox reactions and are formulated as {[SnIV(thd)3]+[MII(hfac)3]−} (MII = Mn (1), Fe (2), Co (3); thd = 2,2,6,6-tetramethyl-3,5-heptanedionate, hfac = hexafluoroacetylacetonate). X-ray single-crystal structural investigations along with DART mass spectrometry, multinuclear NMR, and magnetic susceptibility measurements have been used to confirm an assignment of metal oxidation states in compounds 1−3. Ionic compounds were found to melt congruently at temperatures below the decomposition point. As such, they represent prospective materials that can be utilized as ionic liquids as well as reagents for the soft transfer of diketonate ligands. An unexpected volatility of ionic compounds 1−3 was proposed to occur through a transport reaction, in which the transport agent is one of the products of their partial decomposition in the gas or condensed phase.

A family of tetra-n-butylammonium salts of bis(oxamato)palladate(II) complexes of formula (n-Bu4N)2[Pd(Lm)2]·pH2O [m = 1–9; L1 = N-phenyloxamate (pma) and p = 2 (1), L2 = N-2-methylphenyloxamate (2-Mepma) and p = 4 (2), L3 = N-4-methylphenyloxamate (4-Mepma) and p = 2 (3), L4 = N-2,3-dimethylphenyloxamate (2,3-Me2pma) and p = 3 (4), L5 = N-2,4-dimethylphenyloxamate (Me2pma) and p = 4 (5), L6 = N-2,5-dimethylphenyloxamate (2,5-Me2pma) and p = 7 (6), L7 = N-3,4-dimethylphenyloxamate (3,4-Me2pma) and p = 6 (7), L8 = N-3,5-dimethylphenyloxamate (3,5-Me2pma) and p = 5 (8)] have been prepared and characterized by spectroscopic methods. The crystal structure of 1 that has been solved by single crystal X-ray diffraction shares main structural features with that reported for (n-Bu4N)2[Pd(L9)2]·2CH3CONH2 [L9 = N-2,4,6-dimethylphenyloxamate (2,4,6-Me3pma) and CH3CONH2 = acetamide] (see F.R. Fortea-Perez et al. (2016)). Each palladium atom in 1 is four-coordinate with two oxygen and two nitrogen atoms from two fully deprotonated pma ligands building a centrosymmetric square-planar surrounding, the Pd N/Pd O bond lengths being 2.020(3)/2.003(2) A. The bis(oxamato)palladate(II) units in 1 are well separated from each other by the bulky organic cations, the resulting value of the shortest metal–metal separation being 9.56 A. This series of very stable, phosphine-free, complexes with well-defined structures were shown to efficiently catalyze the Heck reaction of aryl halides with olefins in DMF at 80 °C in 3 h, most likely involving Pd(II)/Pd(IV) species in the vinylation reaction of aryl halides, as well as the Suzuki coupling of aryl halides with arylboronic acids in the same solvent under similar conditions. The reaction conditions for both Heck and Suzuki couplings were optimized by varying the amount of the catalyst, and their scope was systematically studied by using different olefins and aryl halides. The influence of the number and positions of the methyl substituents from the phenyloxamate ligand on the catalytic activity is analyzed and discussed in the light of the results obtained.

This work raises a fundamental question about the “real” structure of molecular compounds containing three different metals: whether they consist of genuine heterotrimetallic species or of a mixture of parent heterobimetallic species. Heterotrimetallic complex Li2CoNi(tbaoac)6 (1, tbaoac = tert-butyl acetoacetate) has been designed based on the model tetranuclear structure featuring two transition metal sites in order to be utilized as a molecular precursor for the low-temperature preparation of the LiCo0.5Ni0.5O2 battery cathode material. An investigation of the structure of 1 appeared to be very challenging, since the Co and Ni atoms have very similar atomic numbers, monoisotopic masses, and radii as well as the same oxidation state and coordination number/environment. Using a statistical analysis of heavily overlaid isotope distribution patterns of the [Li2MM′L5]+ (M/M′ = Co2, Ni2, and CoNi) ions in DART mass spectra, it was concluded that the reaction product 1 contains both heterotrimetallic and bimetallic species. A structural analogue approach has been applied to obtain Li2MMg(tbaoac)6 (M = Co (2) and Ni (3)) complexes that contain lighter, diamagnetic magnesium in the place of one of the 3d transition metals. X-ray crystallography, mass spectrometry, and NMR spectroscopy unambiguously confirmed the presence of three types of molecules in the reaction mixture that reaches an equilibrium, Li2M2L6 + Li2Mg2L6 ↔ 2Li2MMgL6, upon prolonged reflux in solution. The equilibrium mixture was shown to have a nearly statistical distribution of the three molecules, and this is fully supported by the results of theoretical calculations revealing that the stabilization energies of heterotrimetallic assemblies fall exactly in between those for the parent heterobimetallic species. The LiCo0.5Ni0.5O2 quaternary oxide has been obtained in its phase-pure form by thermal decomposition of heterometallic precursor 1 at temperatures as low as 450 °C. Its chemical composition, structure, morphology, and transition metal distribution have been studied by X-ray and electron diffraction techniques and compositional energy-dispersive X-ray mapping with nanometer resolution. The work clearly illustrates the advantages of heterometallic single-source precursors over the corresponding multi-source precursors.

A new synthetic approach based on chemical transport reactions has been introduced to obtain the Nowotny chimney ladder phase Fe2Ge3 in the form of single crystals and polycrystalline powders. The single crystals possess the stoichiometric composition and the commensurate chimney ladder structure of the Ru2Sn3 type in contrast to the polycrystalline samples that are characterized by a complex microstructure. In compliance with the 18-n electron counting rule formulated for T-E intermetallics, electronic structure calculations reveal a narrow-gap semiconducting behavior of Fe2Ge3 favorable for high thermoelectric performance. Measurements of transport and thermoelectric properties performed on the polycrystalline samples confirm the formation of a narrow band gap of similar to 30 meV and reveal high absolute values of the Seebeck coefficient at elevated temperatures. Low glass-like thermal conductivity is observed in a wide temperature range that might be caused by the underlying complex microstructure.

Two new iodobismuthates with the composition LnBiI6•13H2O (Ln = La, Nd) were synthesized and their crystal structures were determined. The compound LaBiI6•13H2O crystalizes in the orthorhombic space group Pna21, a = 24.206(5), b = 8.405(1), c = 26.360(5) A; the compound NdBiI6•13H2O crystalizes in the monoclinic space group P21/n, a = 14.553(3), b = 13.386(3), c = 27.541(6) A, β = 92.80(3)°. In both crystal structures, the cations Ln(H2O)93+ and the anions BiI63– alternate, forming a NaCl-type structure, and the structures themselves differ in the arrangement of water of crystallization that leads to the formation of dissimilar systems of hydrogen bonds. Both compounds undergo decomposition when heated, which is accompanied first by a partial liberation of water molecule, followed by pyrohydrolysis to form oxoiodides LnOI as final solid products. According to optical measurements, the band gap of the obtained compounds was equal to 1.78 (La) and 1.71 (Nd) eV.

Endohedral cluster superconductors are an emerging field, where simple electron counting rules govern the phase stability and transition temperature. Nontrivial microscopic properties of the superc...

Endohedral cluster compounds are a rich source of new superconductors, where nontrivial properties are expected, including strong coupling regime and multigap superconductivity. Here, we report on the synthesis, crystal and electronic structure, and physical properties of the Mo6Ga31 endohedral cluster superconductor. The compound has two crystallographic modifications, monoclinic and triclinic, which are built by the Mo@Ga10 endohedral clusters. Both structures possess qualitatively the same electronic density of states showing a high peak at the Fermi level. Due to the proximity effect of the triclinic and monoclinic domains, which are in the strong contact with each other, bulk Mo6Ga31 exhibits single superconducting transition at the critical temperature of 8.2 K in zero magnetic field. The upper critical field, which is 7.8 T at zero temperature, shows clear enhancement with respect to the Werthamer-Helfand-Honenberg prediction. Accordingly, heat capacity measurements indicate strong electron-phonon coupling in the superconducting state with the large ratio of 2 Δ ( 0 ) / ( k B T c ) = 4.5 , where 2 Δ ( 0 ) = 3.2 meV is the full superconducting gap at zero temperature.

Using the crystal-growth joint flux technique based on the combination of two aliovalent low-melt metals, gallium and zinc, we adjust the gross valence electron count in the Mo-Ga-Zn system and produce the Mo

Three heterometallic single-source precursors with a Li : Fe = 1 : 1 ratio for a LiFeO2 oxide material are reported. Heterometallic compounds LiFeL3 (L = tbaoac (1), ptac (2), and acac(3)) have been obtained on a large scale, in nearly quantitative yields by one-step reactions that employ readily available reagents. The heterometallic precursor LiFe(acac)3 (3) with small, symmetric substituents on the ligand (acac = pentane-2,4-dionate), maintains a 1D polymeric structure in the solid state that limits its volatility and prevents solubility in non-coordinating solvents. The application of the unsymmetrical ligands, tbaoac (tert-butyl acetoacetate) and ptac (1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedionate), that exhibit different bridging properties at the two ends of the ligand, allowed us to change the connectivity pattern within the heterometallic assembly. The latter was demonstrated by structural characterization of heterometallic complexes LiFe(tbaoac)3 (1) and LiFe(ptac)3 (2) that consist of discrete heterocyclic tetranuclear molecules Li2Fe2L6. The compounds are highly volatile and exhibit a congruent sublimation character. DART mass spectrometric investigation revealed the presence of heterometallic molecules in the gas phase. The positive mode spectra are dominated by the presence of [M - L]+ peaks (M = Li2Fe2L6). In accord with their discrete molecular structure, complexes 1 and 2 are highly soluble in nearly all common solvents. In order to test the retention of the heterometallic structure in solution, the diamagnetic analog of 1, LiMg(tbaoac)3 (4), has been isolated. Its tetranuclear molecular structure was found to be isomorphous to that of the iron counterpart. 1H and 7Li NMR spectroscopy unambiguously confirmed the presence of heterometallic molecules in solutions of non-coordinating solvents. The heterometallic precursor 1 was shown to exhibit clean thermal decomposition in air that results in phase-pure α-modification of layered oxide LiFeO2, the prospective cathode material for lithium ion batteries.

The valence state of iron in Cu12−xFexSb4S13 tetrahedrites have been revisited by the combination of the crystallographic results, Mossbauer spectroscopy, and magnetization measurements. The crystal structure solution for Cu11.0Fe1.0Sb4S13 (space group I 4 ¯ 3m, a=10.3253(12), z=2, R=0.011) proved that iron substitutes for copper only in the Cu1 position. At the iron content of x=0.8, 1.0, and 1.2, the presence of two nonequivalent and non-interacting Fe3+ cations was inferred from Mossbauer spectra. At higher levels of substitution (x=1.5 and 2.0), room-temperature Mossbauer spectra indicate the electron hopping between part of Fe3+ and Fe2+ centers, whereas the rest of iron atoms exists as valence-localized Fe3+ and Fe2+ cations. Electron transfer is frozen out at 77 K, where a combination of two Fe3+ sites and one high-spin Fe2+ site is observed. Paramagnetic effective moments extracted from the magnetic susceptibility data point at the Fe3+ state of iron at x=0.8, while a mixture of Fe2+ and Fe3+ is presumed in the samples with higher Fe content.

Heterometallic single-source precursors for the preparation of sodium-rare earth metal fluorides are reported. Fluorinated β-diketonates NaRE(hfac)4 (RE = Y (1), Er (2), and Eu (3); hfac = hexafluoroacetylacetonate) have been obtained on a large scale, in high yield, via one-pot reaction that utilizes commercially available starting reagents. The solid-state structures of the title complexes consist of 1D polymeric chains with alternating [Na] and [RE(hfac)4] units. Compounds 1-3 are highly volatile and exhibit a fair stability in open air. Mass spectrometric investigation indicates the presence of heterometallic fragments in the gas phase. The presence of heterometallic species in solutions of coordinating solvents has also been confirmed. Decomposition of heterometallic precursors in argon atmosphere was shown to yield phase-pure sodium-rare earth metal fluorides. Low decomposition temperature effectively allows for a high degree of control over the formation of both kinetic α-phases and thermodynamic β-phases of target NaREF4 (RE = Y, Er, and Eu) materials.

Four iodobismuthates, LiBiI4·5H2O (1), MgBi2I8·8H2O (2), MnBi2I8·8H2O (3), and KBiI4·H2O (4), were prepared by a facile solution route and revealed thermal stability in air up to 120 °C. Crystal structures of compounds 1-4 were solved by a single crystal X-ray diffraction method. 1: space group C2/c, a = 12.535(2), b = 16.0294(18), c = 7.6214(9) Å, β = 107.189(11)°, Z = 4, R = 0.029. 2: space group P21/c, a = 7.559(2), b = 13.1225(15), c = 13.927(4) Å, β = 97.14(3)°, Z = 2, R = 0.031. 3: space group P21/c, a = 7.606(3), b = 13.137(3), c = 14.026(5) Å, β = 97.14(3)°, Z = 2, R = 0.056. 4: space group P21/n, a = 7.9050(16), b = 7.7718(16), c = 18.233(4) Å, β = 97.45(3)°, Z = 4, R = 0.043. All solid state structures feature one-dimensional (BiI4)(-) anionic chains built of [BiI6] octahedra that share two opposite edges in such a fashion that two iodine atoms in cis-positions remain terminal. The calculated electronic structures and observed optical properties confirmed that compounds 1-4 are semiconductors with direct band gaps of 1.70-1.76 eV, which correspond to their intense red color. It was shown that the cations do not affect the optical properties, and the optical absorption is primarily associated with the charge transfer from the I 5p orbitals at the top of the valence band to the Bi 6p orbitals at the bottom of the conduction band. Based on their properties and facile synthesis, the title compounds are proposed as promising light-harvesting materials for all-solid solar cells.

Endohedral Ga cluster compounds feature nontrivial superconducting states including the two-gap superconductivity similar in nature to MgB2. We use the joint flux synthetic technique to introduce S...

A new compound with a two-dimensional intergrowth structure, Fe32+δGe35-xPx (x = 1.7–4.4, δ = 0.6–0.75), and the solid solution on its base, Fe32+δGe35-x-yPxAsy (δ

This work raises a fundamental question about the "real" structure of molecular compounds containing three different metals: whether they consist of genuine hetero

New heterometallic Sn–Cu compound that contains copper atoms in two different oxidation states was obtained by the solid state reaction between Sn(OBut)2 (OBut = tert-butoxide) and Cu(hfac)2 (hfac = hexafluoroacetylacetonate). Single crystal X-ray diffraction study revealed the ionic structure of a compound that can be formulated as {[CuI3Sn2(OBut)6]+[CuII(hfac)3]−} (1) with no significant interactions between complex cation and anion. The anion is comprised of an octahedrally coordinated by three chelating β-diketonate ligands CuII atom that shows a typical tetragonal Jahn–Teller distortion of the polyhedron. The heterometallic [Cu3Sn2(OBut)6]+ cation features a CuI triangle capped by two Sn(OBut)3 units. All alkoxide ligands are μ2-bridging between Sn and Cu atoms providing a trigonal pyramidal geometry around tin that is consistent with lone pair SnII centers. An almost perfect triangular copper core is stabilized by cuprophilic interactions, similar to those in other polynuclear CuI compounds. The cation represents the first example of a CuI triangular arrangement that is not supported by μ3-centering atoms or by μ2-all-side bridging. Multinuclear NMR studies unambiguously confirm the retention of heterometallic cluster in solution as well as the absence of ligand redistribution between the anion and cation. The use of a mixed-ligand approach creates broad opportunities for designing new heterometallic complexes with unusual architectures that are not observed in homoleptic counterparts.

Nowotny chimney ladder (NCL) phases are intermetallic compounds formed by transition metals and metals of groups 13 and 14. This family can be expanded by combining two p-elements from different groups with those transition metals, for which the corresponding binary NCL phases are unknown. In this paper, we present three new compounds in the V-Al-Ge, Nb-Al-Ge, and Nb-Ga-Ge systems related to the TiSi2 structure type (Sp. Gr. Fddd) obtained with the standard ampule technique. The crystal structures of the new compounds were determined using synchrotron powder X-ray diffraction data. A transition to the CrSi2 structure type was detected upon changing the composition from VAl0.72(2)Ge1.28(2) to VAl1.534(3)Ge0.466(3). According to the 18&ndash, n rule, all the compounds are metallic conductors, which was supported by the electronic structure calculations. It was shown that the expected energy gap located above the Fermi level in the vanadium-based NCL compound collapsed into a pseudogap upon the replacement of V by Nb.

Heterometallic single-source precursors for the Pb/Fe = 1:1 oxide materials, PbFe(β-dik)4 (β-dik = hexafluoroacetylacetonate (hfac, 1), acetylacetonate (acac, 2), and trifluoroacetylacetonate (tfac, 4)), have been isolated by three different solid-state synthetic methods. The crystal structures of heterometallic diketonates 1, 2, and 4 were found to contain polymeric chains built on alternating [Fe(β-dik)2] and [Pb(β-dik)2] units that are held together by bridging M-O interactions. Heterometallic precursors are highly volatile, but soluble only in coordinating solvents, in which they dissociate into solvated homometallic fragments. In order to design the heterometallic precursor with a proper metal/metal ratio and with a discrete molecular structure, we used a combination of two different diketonate ligands. Heteroleptic complex Pb2Fe2(hfac)6(acac)2 (5) has been obtained by optimized stoichiometric reaction of an addition of homo-Fe(acac)2 to heterometallic Pb2Fe(hfac)6 (3) diketonate that can be run in solution on a high scale. The combination of two ligands with electron-withdrawing and electron-donating groups allows changing the connectivity pattern within the heterometallic assembly and yields the precursor with a discrete tetranuclear structure. In accord with its molecular structure, heteroleptic complex 5 is soluble even in noncoordinating solvents and was found to retain its heterometallic structure in solution. Thermal decomposition of heterometallic precursors in air at 750 °C resulted in the target Pb2Fe2O5 oxide, a prospective multiferroic material. Prolonging the annealing time or increasing the decomposition temperature leads to another phase-pure lead-iron oxide PbFe12O19 that is a representative of the important family of magnetic hexaferrites.

Three heterometallic single-source precursors with a proper Li : Co ratio for the lithium ion battery cathode material LiCoO2 are reported. The heterometallic compounds LiCoL3 (L = acac (1), tbaoac (2) or dhd (3)) were obtained on a large scale, in nearly quantitative yield using a one-step reaction that employs readily available starting reagents. The first of these precursors, heterometallic diketonate LiCo(acac)3 (1) (acac = pentane-2,4-dionate), was found to have a polymeric structure in the solid state that limits its volatility and prevents solubility in non-coordinating solvents. In order to design precursors with discrete molecular structures, we used asymmetric ligands, tert-butyl acetoacetate (tbaoac) and 2,2-dimethyl-hexanedionate (dhd), that exhibit different bridging properties at the two ends of the ligand and thus allow one to effectively change the bridging connectivity pattern within the heterometallic assembly. As a result, the heterometallic complexes LiCo(tbaoac)3 (2) and LiCo(dhd)3 (3), which consist of discrete tetranuclear molecules of Li2Co2L6, were successfully isolated and characterized. Out of the three heterometallic compounds reported in this work, LiCo(tbaoac)3 (2) appears to meet the application demands for an ideal single-source precursor. In accord with its discrete molecular structure, the complex is soluble in nearly all common solvents and retains its heterometallic structure in solution. Thus, it can be effectively used for the preparation of thin films by direct liquid injection techniques. The compound is highly volatile and exhibits a congruent sublimation with heterometallic fragments present in the gas phase. In addition, it shows the lowest decomposition temperature leading to phase-pure LiCoO2 and can be utilized for the preparation of nanoparticles of this cathode material. Importantly, single-source precursor 2 does not impose any measurable ligand extra cost on the formation of the target cathode material.

The crystal structure of a tin-rich heterometallic supramolecular product, [CuSn8(C5HF6O2)2(C5H2F6O4)4] or [Sn4(hfpt)2–Cu(hfac)2–Sn4(hfpt)2], (I), is reported (hfpt is the tetraanion of 1,1,1,5,5,5-hexafluoropentane-2,2,4,4-tetraol and hfac is the anion of 1,1,1,5,5,5-hexafluoropentane-2,4-dione). Reaction between tin(II) tetraolate, [Sn4(hfpt)2], and copper(II) β-diketonate, [Cu(hfac)2], was utilized for the preparation of (I). The asymmetric unit consists of the whole [Sn4(hfpt)2] unit and half of a [Cu(hfac)2] unit, with the Cu atom lying on an inversion center. Intermolecular Cu...O interactions from the axial positions of copper in [Cu(hfac)2] and O atoms of the hfpt ligand in [Sn4(hfpt)2] mediate the formation of a sandwich-type structure for (I). Additional intermolecular Sn...O interactions between neighbouring [Sn4(hfpt)2] units complete a two-dimensional network.

Four iodobismuthates, LiBiI4·5H2O (1), MgBi2I8·8H2O (2), MnBi2I8·8H2O (3), and KBiI4·H2O (4), were prepared by a facile solution route and revealed thermal stability in air up to 120 °C. Crystal structures of compounds 1–4 were solved by a single crystal X-ray diffraction method. 1: space group C2/c, a = 12.535(2), b = 16.0294(18), c = 7.6214(9) A, β = 107.189(11)°, Z = 4, R = 0.029. 2: space group P21/c, a = 7.559(2), b = 13.1225(15), c = 13.927(4) A, β = 97.14(3)°, Z = 2, R = 0.031. 3: space group P21/c, a = 7.606(3), b = 13.137(3), c = 14.026(5) A, β = 97.14(3)°, Z = 2, R = 0.056. 4: space group P21/n, a = 7.9050(16), b = 7.7718(16), c = 18.233(4) A, β = 97.45(3)°, Z = 4, R = 0.043. All solid state structures feature one-dimensional (BiI4)− anionic chains built of [BiI6] octahedra that share two opposite edges in such a fashion that two iodine atoms in cis-positions remain terminal. The calculated electronic structures and observed optical properties confirmed that compounds 1–4 are semiconductors with...

A new series of heteroleptic bismuth-transition metal β-diketonates [BiM(hfac)3(thd)2] (M = Mn (1), Co (2), and Ni (3); hfac = hexafluoroacetylacetonate, thd = tetramethylheptanedionate) with Bi:M = 1:1 ratio have been synthesized by stoichiometric reactions between homometallic reagents [Bi(III)(hfac)3] and [M(II)(thd)2]. On the basis of analysis of the metal-ligand interactions in heterometallic structures, the title compounds were formulated as ion-pair {[Bi(III)(thd)2](+)[M(II)(hfac)3](-)} complexes. The direct reaction between homometallic reagents proceeds with a full ligand exchange between main group and transition metal centers, yielding dinuclear heterometallic molecules. In heteroleptic molecules 1-3, the Lewis acidic, coordinatively unsaturated Bi(III) centers are chelated by two bulky, electron-donating thd ligands and maintain bridging interactions with three oxygen atoms of small, electron-withdrawing hfac groups that chelate the neighboring divalent transition metals. Application of the mixed-ligand approach allows one to change the connectivity pattern within the heterometallic assembly and to isolate highly volatile precursors with the proper Bi:M = 1:1 ratio. The mixed-ligand approach employed in this work opens broad opportunities for the synthesis of heterometallic (main group-transition metal) molecular precursors with specific M:M' ratio in the case when homoleptic counterparts either do not exist or afford products with an incorrect metal:metal ratio for the target materials. Heteroleptic complexes obtained in the course of this study represent prospective single-source precursors for the low-temperature preparation of multiferroic perovskite-type oxides.

The new cationic clathrates I Si30P16Te8–xSex and Si30+xP16–xTe8–xBrx were synthesized by the standard ampule technique. The Si30P16Te8–xSex (x = 0–2.3) clathrates crystallize in the cubic space group Pm3n with the unit cell parameter a ranging from 9.9382(2) to 9.9696(1) A. In the case of the Si30+xP16–xTe8–xBrx (x = 1–6.4) clathrates, the lattice parameter varies from 9.9720(8) to 10.0405(1) A; at lower Si/P ratios (x = 1–3) the ordering of bromine atoms induces the splitting of the guest positions and causes the transformation from the space group Pm3n to Pm3. Irrespective of the structure peculiarities, the normal temperature motion of the guest atoms inside the oversized cages of the framework is observed. The title clathrates possess very low thermal expansion coefficients ranging from 6.6 × 10–6 to 1.0 × 10–5 K–1 in the temperature range of 298–1100 K. The characteristic Debye temperature is about 490 K. Measurements of the electrical resistivity and thermopower showed typical behavior of p-type...

Two complexes, cis ( 1 ) and trans ( 2 ) (Au p NBT) 2 dppee ( p NBT = p -nitrobenzenethiol; dppee = bis(diphenylphosphino)ethylene) have been synthesized and characterized. X-ray diffraction studies reveal that cis -(Au p NBT) 2 dppee has an intramolecular gold–gold distance of 3.0036(3) A while the trans -(Au p NBT) 2 dppee crystal is a dimer with an intermolecular gold–gold distance of 3.1201(4) A. We have used UV–Vis spectroscopy, 1 H NMR, and 31 P { 1 H} NMR to investigate the photochemical reactivity of both complexes. In a range of organic solvents with λ > 230 nm cis -(Au p NBT) 2 dppee readily isomerizes to the trans isomer. Under these same conditions, the trans isomer does not isomerize to cis -(Au p NBT) 2 dppee, but undergoes a photochemical substitution reaction. In chlorinated solvents (CH 2 Cl 2 , CH 3 Cl) trans -(Au p NBT) 2 dppee reacts to form trans -(AuCl) 2 dppee ( 3 ) which crystallizes into an extended chain of molecules linked via intermolecular gold–gold distances of 3.0203(2) A. TDDFT calculations support the observed experimental results. We propose that at high energies the reaction is initiated by chlorine radicals from direct photolysis of the solvent. At longer wavelengths the excited state of the metal complex is the photoactive species, abstracting a chlorine radical from the solvent.

The crystal structure of the thermoelectric clathrate Sn 24 P 19.3 I 8 was determined down to 10 K showing no variations with the temperature. Even at 10 K Sn 24 P 19.3 I 8 crystallizes in the type-I clathrate structure, space group Pm3-n, with the cubic unit cell parameter ranging from 10.9173 A at 10 K to 10.9554 A at room temperature. In its crystal structure, tin and phosphorus atoms form the framework that traps the guest iodine atoms in the polyhedral cavities of two different shapes. The temperature-dependent crystal structure data and the results of the heat capacity measurements revealed the localized vibrations of the guest atoms inside the oversized cavities with the characteristic Einstein temperatures of θ E 1 = 60 K and θ E 2 = 78 K, whereas the characteristic Debye temperature for Sn 24 P 19.3 I 8 is 265 K. The room temperature lattice thermal conductivity was calculated using the Debye model to be κ L = 0.85 W m −1 K −1 , which is in excellent agreement with the experimentally measured data and demonstrates that the thermal conductivity is almost entirely phononic.

Recyclable and efficient heterogeneous catalysts have been prepared by embedding dirhodium(II,II) core carboxylate complexes into the amine-functionalized nanosized channels of a mesoporous silica host, amine-SBA-15. Two alternative synthetic procedures for the preparation of the catalysts have been developed and adapted for the immobilization of dirhodium complexes of variable Lewis acidity. The catalytic activity of the resulting solid materials has been evaluated in model cyclopropanation reactions of styrene at variable reaction conditions (reaction substrate, temperature, time, and solvent). Importantly, the designed catalysts, which can be readily recovered and reused, display the reactivity and selectivity profiles exceeding or comparable to their homogeneous dirhodium(II) counterparts.

The catalytic activity of heterobimetallic Bi-Rh paddlewheel carboxylate complexes has been evaluated for the first time in the context of metal carbenoid chemistry. The Bi-Rh carboxylate complexes were found to effectively catalyze both cyclopropanation reactions and C-H insertions as well as reactions involving ylide intermediates with similar selectivity profiles to analogous dirhodium complexes. The heterometallic complex BiRh(O(2)CCF(3))(3)(O(2)CCH(3)) was found to be approximately 1600 times less reactive than its homometallic analogue Rh(2)(O(2)CCF(3))(3)(O(2)CCH(3)) toward the decomposition of methyl phenyldiazoacetate. The observed difference in reactivity is in good agreement with a computational model system where axial coordination to the second rhodium active site is considered for the dirhodium catalyst.

The heterometallic complex i(2)Pd(2) O2CC (3) (10) O2CC (3) (2) 1) was obtained by the solid state reaction of Bi-III trifluoroacetate trifluoroacetic acid adduct with unsolvated trinuclear Pd-II trifluoroacetate. he crystal structure of 1 consists of discrete tetranuclear molecules, in which two paddlewheel [BiPd(O2CC (3) (4) units are connected by two chelating bridging trifluoroacetate ligands through bismuth ends. here are no metal-metal bonds in the tetrameric structure of 1, since both Bi center dot center dot center dot Pd (3,0843(4) A and i center dot center dot center dot Bi (4.5074(4) A distances am too king to be considered as bonding interactions. A study of (he solution behavior revealed that not only die coordinated trifluoacetic acid in 1 can be effectively replaced by other donor solvent molecules but also the tetranuclear complex can be cleaved in solution into discrete dinuclear i-Pd species. Complex 1 was used as precursor for the preparation of a bimetallic Pd-Bi carbon supported catalyst. lie preparation procedure included the modification of the carbon support to increase the number of oxygenated function at its surface followed by grafting complex 1 via ligand exchange for surface carboxylates and activating the thermally.. he resulting catalyst consisting of small supported metallic particles was found to be more active than the reference materials prepared from multisource homometallic Pd and i precursors.