Missing Carbodiimide and Oxide Carbodiimide of Scandium: Sc2(CN2)3 and Sc2O2(CN2)

The new scandium(III) carbodiimides Sc₂(CN₂)₃ and Sc₂O₂(CN₂) were prepared by solid-state metathesis reactions between Li₂(CN₂) and ScCl₃ and, regarding Sc₂O₂(CN₂), Sc₂O₃ was added. The X-ray powder diffraction pattern refinements lead to a trigonal-rhombohedral (R3 c) crystal system for Sc₂(CN₂)₃ and to an orthorhombic (Immm) crystal system for Sc₂O₂(CN₂). The structure of Sc₂(CN₂)₃ is isotypic to the well-known rare earth carbodiimides RE₂(CN₂)₃ with the smaller cations RE = Tm, Yb, and Lu, whereas Sc₂O₂(CN₂) is not isotypic to the known RE₂O₂(CN₂) (RE = Y, La, Ce–Gd, except Pm) compounds. Both crystal structures are represented by layered arrangements of scandium, respectively scandium and oxide, alternating with carbodiimide layers.     

Synthesis of Er5(BO3)2F9 and Properties of RE5(BO3)2F9 (RE = Er,Yb)

Er₅(BO₃)₂F₉ was synthesised under conditions of 3 GPa and 800 °C in a Walker‐type multianvil apparatus. The crystal structure was determined on the basis of single‐crystal X‐ray diffraction data, collected at room temperature. Er₅(BO₃)₂F₉ is isotypic to the recently synthesised Yb₅(BO₃)₂F₉ and crystallises in C2/c with the lattice parameters a = 2031.2(4) pm, b = 609.5(2) pm, c = 824.6(2) pm, and β = 100.29(3)°. The physical properties of RE₅(BO₃)₂F₉ (RE = Er, Yb) including high temperature behaviour and single crystal IR‐ / Raman spectroscopy were investigated.     

Synthesis and Crystal Structure of LiY(CN2)2, Having a Structure Related to That of NiAs

The new ternary carbodiimide LiY(CN₂)₂ was synthesized by solid state metathesis reaction between YF₃ and Li₂(CN₂) in a silica tube at 550 °C. The X‐ray single‐crystal structure determination yielded an orthorhombic crystal system (Pbcn, Z = 4, a = 982.0(3), b = 698.5(2), c = 613.4(2) pm). The crystal structure can be considered related to the NiAs structure. The carbodiimide ions are arranged in layers following the motif of a hexagonal closest packing of sticks. Lithium and yttrium cations occupy all octahedral voids in an ordered fashion, alternating on top of each other along the hcp stacking direction.     

Die Kristallstrukturen der Cyanidofluoridoborate K[BFx(CN)4–x], x = 0–4

The crystal structure of K[BF₃(CN)] (Pbcn (Nr. 60) with a = 13.3486(15) b = 6.5239(7) c = 10.0085(11) Å, and eight formula units per unit cell) has been determined and the one of K[BF₂(CN)₂] was confirmed and improved. The different networks in the complete series of borates K[BF_x(CN)_4–x], x = 0–4 are compared and discussed.     

Rebuttal of the Existence of Solid Rare Earth Bicarbonates and the Crystal Structure of Holmium Nitrate Pentahydrate

The synthesis routes of Gd(HCO₃)₃ · 5H₂O and Ho(HCO₃)₃ · 6H₂O, which are the only known bicarbonates of rare earth metals, were refuted and the published crystal structures were discussed. Because of the structural relationship of Ho(HCO₃)₃ · 6H₂O to rare earth nitrate hexahydrates, 1 the synthesis of holmium nitrate hydrate was considered and the crystal structure of Ho(NO₃)₃ · 5H₂O was solved by single crystal X‐ray diffraction measurements. Ho(NO₃)₃ · 5H₂O was determined to crystallize in the triclinic space group P1 (no. 2) with a = 6.5680(14) Å, b = 9.503(2) Å, c = 10.462(2) Å, α = 63.739(14)°, β = 94.042(2)° and γ = 76.000(16)°. The crystal structure consists of isolated [Ho(H₂O)₄(NO₃)₃] polyhedra and non‐coordinating water molecules. It is isotypic to other rare earth nitrate pentahydrates.     

New Ternary Boride Carbides RE10B9+xC10–x (RE = Gd,Tb; x ≈︁ 0.2): Infinite Boron Carbon Branched Chains

New ternary rare earth metal boride carbides with compositions close to RE₁₀B₉C₁₀ (RE = Gd, Tb) were prepared from the elements by melting around 1800 K followed by annealing in silica tubes at 1270 K for one month. The crystal structure of the terbium compound was solved by single‐crystal X‐ray diffraction. It crystallizes in a new structure type in the monoclinic space group P2₁/c, a = 7.937(1), b = 23.786(2), c = 11.172(1) Å, β = 133.74(1)°, Z = 4, R1 = 0.045 (wR2 = 0.11) for 5713 reflections with I_o > 2σ(I_o). In the structure BC₂ units and single carbon atoms are attached to a zigzag boron chain forming the unprecedented B₁₈C₁₈ branching unit with a B–B distance of 2.42(2) Å between these units. In addition isolated carbon atoms occupy the centres of elongated octahedra formed by rare earth metal atoms. Disorder in the terbium position together with anomalous displacement ellipsoids for carbon atoms except of those in the BC₂ fragments can be rationalized in terms of a slight deviation in stoichiometry, Tb₁₀B_9+xC_10–x (x ≈? 0.2). The terbium compound is ferromagnetic below T_C ≈? 45 K. Due to the presence of moderately narrow domain walls the magneto‐crystalline energy is small.     

Photomagnetic Switching of the Complex [Nd(dmf)4(H2O)3(μ‐CN)Fe(CN)5]⋅H2O Analyzed by Single‐Crystal X‐Ray Diffraction

X‐ray vision : Single‐crystal XRD experiments (see picture) reveal the excited‐state structure of the photomagnetic heterobimetallic title complex. The system shows a decrease in all the iron–ligand bond lengths, suggesting that photoexcitation involves a ligand‐to‐metal charge transfer or a change in the superexchange coupling between the metal centers.

     

A New Main Group Metal Coordination Polymer: Synthesis,Structure, and Dielectric Constant Property of [Na(C6H4N5)(H2O)2]n

The reaction of NaOH with 4‐(2H‐tetrazol‐5‐yl)pyridine affords the first tetrazole‐pyridine sodium coordination polymer with chain structure, [Na(C₆H₄N₅)(H₂O)₂]_n ( 1 ). The compound could be characterized by single‐crystal X‐ray diffraction analysis. The temperature dependence of dielectric permittivity remains unchanged almost within the measured temperature range of 80 K to 270 K at 1 <SC>MH</SC>z, and the frequency dependence of the permittivity showed rapidly drops from 31.5 to 4.3 within the measured frequency range of 200 to 1 MHz at room temperature.     

Pr3Mo4B6O24(OH)3: High-Pressure/High-Temperature Synthesis of an Acentric Rare Earth Molybdenum Borate

We report on the synthesis of a new praseodymium molybdenum borate under high-pressure/high-temperature conditions. The new compound with the sum formula Pr₃Mo₄B₆O₂₄(OH)₃ crystallizes acentrically in the monoclinic space group Cm displaying a new structure type. The structure was solved via single-crystal structure determination. Additionally, the proposed structural model was confirmed by powder X-ray diffraction, second harmonic generation measurement, and single-crystal infrared and Raman spectroscopic investigation.     

Photomagnetic Switching of Heterometallic Complexes [M(dmf)4(H2O)3(μ‐CN)Fe(CN)5]⋅H2O (M=Nd,La, Gd,Y) Analyzed by Single‐Crystal X‐ray Diffraction and Ab Initio Theory

Single‐crystal X‐ray diffraction measurements have been carried out on [Nd(dmf)₄(H₂O)₃(μ‐CN)Fe(CN)₅]?H₂O ( 1 ; dmf=dimethylformamide), [Nd(dmf)₄(H₂O)₃(μ‐CN)Co(CN)₅]?H₂O ( 2 ), [La(dmf)₄(H₂O)₃(μ‐CN)Fe(CN)₅]?H₂O ( 3 ), [Gd(dmf)₄(H₂O)₃(μ‐CN)Fe(CN)₅]?H₂O ( 4 ), and [Y(dmf)₄(H₂O)₃(μ‐CN)Fe(CN)₅]?H₂O ( 5 ), at 15(2) K with and without UV illumination of the crystals. Significant changes in unit‐cell parameters were observed for all the iron‐containing complexes, whereas 2 showed no response to UV illumination. Photoexcited crystal structures have been determined for 1 , 3 , and 4 based on refinements of two‐conformer models, and excited‐state occupancies of 78.6(1), 84(6), and 86.6(7) % were reached, respectively. Significant bond‐length changes were observed for the Fe–ligand bonds (up to 0.19 Å), the cyano bonds (up to 0.09 Å), and the lanthanide–ligand bonds (up to 0.10 Å). Ab initio theoretical calculations were carried out for the experimental ground‐state geometry of 1 to understand the electronic structure changes upon UV illumination. The calculations suggest that UV illumination gives a charge transfer from the cyano groups on the iron atom to the lanthanide ion moiety, {Nd(dmf)₄(H₂O)₃}, with a distance of approximately 6 Å from the iron atom. The charge transfer is accompanied by a reorganization of the spin state on the {Fe(CN)₆} complex, and a change in geometry that produces a metastable charge‐transfer state with an increased number of unpaired electrons, thus accounting for the observed photomagnetic effect.     

Hydrated Rare Earth Structural Networks containing the Phenylene‐1, 2‐dioxydiacetate (PDDA) Ligand

Reaction of LnCl₃ with Na₂(PDDA) (PDDA = phenylene‐1, 2‐dioxydiacetate) in a 1 to 2 mol ratio in aqueous solution yielded [Ln₂(PDDA)₃(H₂O)₆] · 2H₂O, structurally characterized for Ln = Ce ( 1 ), Sm ( 2 ) (redetermination), Tb ( 3 ) and Y ( 4 ) in a monoclinic C2/c array, a second related structural form [orthorhombic, Pbcn] being obtained for Tb ( 5 ), Ho ( 6 ) and Er ( 7 ). The ‘domains of existence' of these two previously described forms are now extended to Ce–Dy, Y, and Eu–Er, respectively. Reaction under the same conditions for the heavier Yb³⁺ ion yielded [Yb₂(PDDA)₃(H₂O)₆]_(∞|∞) · 4H₂O ( 8 ), orthorhombic, Pbca. In the case of Ln = La the bimetallic species [NaLa(PDDA)₂(H₂O)₂]_(∞|∞) · 4H₂O ( 9 ) was obtained, while reaction of LnCl₃ with Na₂(PDDA) in a 1 to 3 mol ratio led to the isolation of the isotypic (monoclinic, P2₁/c) [NaLn(PDDA)₂(H₂O)₂]_(∞|∞) · 4H₂O) for Ln = Ce ( 10 ) and Sm ( 12 ). With the smaller Ln = Yb, the more definitively bimetallic [NaYb(PDDA)₂(H₂O)₂]_(∞|∞) · 3H₂O ( 13 ) (triclinic, P$\bar{1}$ )) was obtained, the trihydrate solvation ascribed differing from that recorded (dihydrate) in a cosynchronous report.     

Synthesis and Investigation of 1,3‐Bis(5‐nitraminotetrazol‐1‐yl)propan‐2‐ol and its Salts

1,3‐Bis(5‐nitraminotetrazol‐1‐yl)propan‐2‐ol ( 5 ) was prepared by the reaction of 5‐aminotetrazole and 1,3‐dichloroisopropanol under basic conditions. Obtained 1,3‐bis(5‐aminotetrazol‐1‐yl)propan‐2‐ol ( 3 ) was nitrated with 100 % nitric acid. In this context in situ hydrolysis of the nitrate ester was studied. Metal and nitrogen‐rich salts of the neutral compound 5 were prepared and analyzed. Crystal structures of three salts and the sensitivities toward impact, friction and electrostatic discharge were determined as well. The performance values of the compounds were calculated using the EXPLO5 program. A detailed comparison of the different salts is also enclosed.     

Composition and Crystal Structure of SmSb2O4Cl Revisited – and the Analogy of Sm1.5Sb1.5O4Br

The quaternary halide‐containing samarium(III) oxidoantimonates(III) Sm_1.3Sb_1.7O₄Cl and Sm_1.5Sb_1.5O₄Br were synthesized through solid‐state reactions from the binary components (Sm₂O₃, Sb₂O₃ and SmX₃, X = Cl and Br) at 750 °C in evacuated fused silica ampoules. They crystallize tetragonally in the space group P4/mmm, like the basically isotypic bismuthate(III) compounds SmBi₂O₄Cl and SmBi₂O₄Br, but show larger molar volumes and therefore contradict an ideal composition of “SmSb₂O₄X” (X = Cl and Br). Both single‐crystal X‐ray diffraction and quantitative electron‐beam microprobe analysis revealed the actual compositions of the investigated antimony(III) compounds, which can be understood as heavily Sm³⁺‐doped derivatives of “SmSb₂O₄X” hosts at the Sb³⁺ site. (Sm1)³⁺ is coordinated eightfold by oxygen atoms in the shape of a cube. The mixed‐occupied (Sb/Sm2)³⁺ cation has four oxygen atoms and four halide anions as neighbors forming a square antiprism. The oxygen atoms and anions establish alternating layers parallel to the ab‐plane, which alternate when stacked along [001].     

Discrete [Yb(NCS)3(H2O)5] Molecules in Pentaaquatriisothiocyanatoytterbium(III) Monohydrate

Single crystals of [Yb(NCS)₃(H₂O)₅] · H₂O were synthesized from a salt‐metathesis reaction between stoichiometric amounts of aqueous solutions of Yb₂(SO₄)₃ · 8H₂O and Ba(NCS)₂ · 3H₂O driven by the precipitation of Ba(SO₄), followed by isothermic evaporation of the filtered‐off solution at room temperature under atmospheric conditions. These crystals of the title compound came as transparent, colorless and hygroscopic needles. According to the X‐ray diffraction structure analysis [Yb(NCS)₃(H₂O)₅] · H₂O crystallizes in the monoclinic space group P2₁ with the lattice parameters a = 845.38(5), b = 719.26(4), c = 1219.65(7) pm, β = 103.852(3)° for Z = 2. The acentric crystal structure contains crystallographically unique Yb³⁺ cations, each surrounded by three thiocyanate anions, all grafting with their nitrogen atoms, and five water molecules forming a neutral [Yb(NCS)₃(H₂O)₅] complex with square antiprismatic shape, completed by a sixth interstitial water molecule. ATR‐FT infrared and single‐crystal Raman spectra of [Yb(NCS)₃(H₂O)₅] · H₂O confirm these findings.     

A Highly Reactive Seven‐Coordinate Osmium(V) Oxo Complex: [OsV(O)(qpy)(pic)Cl]2+

Seven‐coordinate ruthenium oxo species have been proposed as active intermediates in catalytic water oxidation by a number of highly active ruthenium catalysts, however such species have yet to be isolated. Reported herein is the first example of a seven‐coordinate group 8 metal‐oxo species, [Os^V(O)(qpy)(pic)Cl]²⁺ (qpy=2,2′:6′,2′′:6′′,2′′′‐quaterpyridine, pic=4‐picoline). The X‐ray crystal structure of this complex shows that it has a distorted pentagonal bipyramidal geometry with an Os?O distance of 1.7375 Å. This oxo species undergoes facile O‐atom and H‐atom‐transfer reactions with various organic substrates. Notably it can abstract H atoms from alkylaromatics with C? H bond dissociation energy as high as 90 kcal mol^?1. This work suggests that highly active oxidants may be designed based on group 8 seven‐coordinate metal oxo species.     

Bulky Cations and Four different Polyiodide Anions in [Lu(Db18c6)(H2O)3(thf)6]4(I3)2(I5)6(I8)(I12)

Black single crystals of [Lu(Db18c6)(H₂O)₃(thf)₆]₄(I₃)₂(I₅)₆(I₈)(I₁₂) were obtained from lutetium, I₂ and Db18c6 (dibenzo‐18‐crown‐6) in THF solution. In the bulky cation, Lu³⁺ is surrounded by nine oxygen atoms, six of Db18c6 and three of water molecules to which two THF molecules are attached each. Meanwhile, four polyiodide anions, (I₃)^–, (I₅)^–, (I₈)^2– and (I₁₂)^2–, in a 2:6:1:1 ratio form a three‐dimensional network and leave space for the bulky cations.     

Completing the Series: New Coordination Networks of Composition 3∞[RE2(ADC)3(H2O)6]·2H2O with RE = Pr,Nd, Sm,Eu, Tb,Dy, Ho,Er, Y and ADC2– = Acetylenedicarboxylate (–O2C–C≡C–CO2–)

The crystal structures of ³_∞[RE₂(ADC)₃(H₂O)₆] · 2H₂O (RE = Pr, Nd, Sm, Eu, Tb, Dy) were solved and refined from X‐ray single crystal data. They crystallize in a structure type already known for RE = La, Ce and Gd (P1 , no. 2, Z = 2), which is characterized by REO₉ polyhedra forming dimeric units being the nodes of a 3D framework structure linked by ADC^2– anions (^–O₂C–C≡C–CO₂^– = acetylenedicarboxylate). From synchrotron powder diffraction data it was shown that isostructural coordination networks are formed for RE = Ho, Er, Y, whereas for RE = Tm, Yb, Lu a new structure type crystallizing in a highly complex crystal structure with a large orthorhombic unit cell is found. All compounds are obtained by slow evaporation of an aqueous solution containing RE(OAc)₃ · xH₂O and acetylenedicarboxylic acid (H₂ADC). The coordination networks of composition ³_∞[RE₂(ADC)₃(H₂O)₆] · 2H₂O were thoroughly investigated by thermal analysis and for RE = Eu, Tb, a strong red and green photoluminescence was observed and investigated by means of UV/Vis spectroscopy.     

High-spin- and low-spin-state structures of [Fe(chloroethyltetrazole)6](ClO4)2 from synchrotron powder diffraction data

The spin-crossover complex [Fe(teec)(6)](ClO(4))(2) (teec = chloroethyltetrazole) exhibits a 50 % incomplete spin crossover in the temperature range 300-30 K. Time-resolved synchrotron powder diffraction experiments have been carried out to elucidate its structural behavior. We report crystal structure models of this material at 300 K (high spin) and 90 K (low spin), as solved from synchrotron powder diffraction data by using Genetic Algorithm and Parallel Tempering techniques and refined with Rietveld refinement. During short synchrotron powder diffraction experiments (five minutes duration) two distinguishable lattices were observed the quantities of which vary with temperature. The implication of this phenomenon, that is interpreted as a structural phase transition associated with the high-to-low spin crossover, and the structural characteristics of the high-spin and low-spin models are discussed in relation to other compounds showing a similar type of spin-crossover behavior.