Volume 61, Issue 7

Light blue [Cu(CN)en 2 ]I was prepared by reaction of copper iodide with ethylenediamine (en) and potassium cyanide in acetonitrile in air. It crystallizes in the space group C2 (No. 5) with a = 11.082(6), b = 7.155(2), c = 9.017(3) Å , β = 127.00(3)°, and Z = 2. The structure was refined from 1069 unique reflections and 90 parameters. The refinement converged to R1=0.018 and wR2=0.041 (all reflections). Copper has a trigonal bi-pyramidal environment formed by two en molecules and one CN− anion. The iodine anion shows no direct contact to the Cu 2+ center. The propeller shaped complexes [Cu(CN)en 2 ] + are all oriented parallel in the crystal structure. [Cu(CN)en 2 ] + cations and I − anions form a zincblende related arrangement.

The crystal structures of several new compounds have been determined using X-ray analysis. The intermetallic compound HoZn 5 Al 3 (a = 8.586(3), c = 16.538(5) Å , RF = 0.0413, RW = 0.0521) has its own structure type (space group I4/mmm), which has been found for the first time. The following compounds are isostructural with the previous one: YZn 5.52 Al 2.48 (a = 8.6183(1), c = 16.5048(3) Å , RI = 0.078, RP = 0.116), DyZn 4.96 Al 3.04 (a = 8.5887(1), c = 16.5002(3) Å , RI = 0.077, RP = 0.114), ErZn 5.37 Al 2.63 (a = 8.5525(2), c =16.3997(5) Å , RI = 0.081, RP = 0.111), TmZn 5.64 Al 2.36 (a = 8.70429(8), c = 16.3943(4) Å , RI = 0.088, RP = 0.095), LuZn 5.58 Al 2.42 (a = 8.5616(1), c= 16.3052(3) Å , RI =0.081, RP =0.101). The intermetallic compound Yb 4 Zn 20.3 Al 12.7 (a = 8.6183(1), c = 16.5048(3) Å , RI = 0.085, RP = 0.112) adopts the Yb 8 Cu 17 Al 49 - type structure (space group I4/mmm). The relationship between the HoZn 5 Al 3 -type and the Yb 8 Cu 17 Al 49 -type structures is discussed.

Crystals of Bi 3 Ni were synthesized using iodine as mineralizer. X-ray diffraction on a single-crystal including transmission-optimized measurement and optimized absorption correction (μ(Mo-K α ) = 1302 cm −1 ) results in a structure model (Pnma; a = 887.96(7), b = 409.97(3), c = 1147.8(1) pm) with significant deviations in interatomic distances compared with previous data from X-ray and neutron investigations. From quantum chemical calculations and from the structural chemistry of the subhalides related to Bi 3 Ni the chemical structure of the intermetallic compound can be derived. In the crystal structure the Ni atoms have a capped trigonal prismatic coordination of Bi atoms with strong bonds Ni-Bi and Ni-Ni. The prisms constitute rods 1 ∞ [NiBi 1 / 1 Bi 6 / 3 ] by sharing the non-capped square faces. The bonding between the intermetallic rods is clearly weaker than inside them, leading to a preservation of this structural fragment in the subhalides of Bi 3 Ni. In accordance with the low temperature superconductivity of the compound, its electronic band structure shows steep and flat bands at the Fermi level. DFT and ELF calculations reveal a separation of delocalized conduction electrons inside the prism rods and largely localized valence electrons between them.

The reaction of a melt of unsubstituted imidazole with praseodymium metal yields bright green crystals of 3D-[Pr(Im) 3 (ImH)]@ImH. Imidazolate ligands coordinate η 1 via both N atoms their 1,3 positioning within the heterocycle being responsible for the connection of praseodymium atoms. A 3-dimensional network is formed with imidazole molecules from the melt intercalated in the crystal structure. The imidazole molecules can be released and temperature dependent reversibly be exchanged with gas molecules including argon. Thus the solvent free high temperature synthesis of rare earth elements with amine melts can also be utilized for “crystal engineering” and the synthesis of compounds with material science aspects. Furthermore 3D-[Pr(Im) 3 (ImH)]@ImH is the first unsubstituted imidazolate of the lanthanides.

Materials chemistry under high pressures is an important research area opening new routes for stabilizing novel materials or original structures with different compositions (oxides, oxoborates, nitrides, nitridophosphates, sulfides,. . .). Due to the varieties of chemical compositions and structures involved, high pressure technology is also an important tool for improving the investigations on chemical bonding and consequently the induced physico-chemical properties. Two different approaches can be described: (i) the chemical bond is pre-existing and in such a case, high pressures lead to structural transformations, (ii) the chemical bond does not exist and high pressures are able to help the synthesis of novel materials. In both cases the condensation effect (ΔV < 0 between precursors and the final product) is the general rule. In addition, through the improvement of the reactivity, high pressures can lead to materials that are not reachable through other chemical routes.

New NH 4 M II M III F 6 and M II M III F 5 ・ 2H 2 O compounds with the pyrochlore and weberite structures, respectively, are reported. Structures of NH 4 CoCrF 6 , AlZnF 5 ・ 2H 2 O, and GaMnF 5 ・ 2H 2 O were refined using X-ray diffraction data from single crystals. The structures of Mg II Al III F 5 ・H 2 O and NH 4 Mg II Al III F 6 were refined from powder X-ray diffraction data. Magnetic susceptibility data indicates antiferromagnetic ordering in NH 4 Co II V III F 6 at 7 K but no ordering in NH 4 Co II Cr III F 6 down to 4.2 K. Electrical conductivity presumably due to protons was observed in MgAlF 5 ・ (H 2 O) 2 .

The ternary compounds (RE 3 N)Sn with RE = La, Ce, Pr, Nd, Sm were prepared starting from the elements. The compounds with RE = La, Ce, Pr were obtained as single phase materials according to X-ray powder diffraction patterns, which also indicate the cubic inverse perovskite crystal structure (space group Pm3̄m, La: a = 509.48(2) pm, Ce: a = 501.59(2) pm, Pr: a = 497.53(2) pm, Nd: a = 494.70(5) pm, Sm: a =488.35(9) pm). Chemical analyses proof the correct composition and particularly the absence of nonmetallic constituents next to nitrogen. All studied compounds show metallic characteristics in the electrical resistivity. Magnetic susceptibility measurements indicate (La 3 N)Sn to be a Pauli-paramagnet. Initially observed superconductivity was traced down to be due to thin La films on the surface of the grains. The Ce and Pr containing compounds show the behavior of 4f 1 ions and 4f 2 ions, and order antiferromagnetically at 6.8(2) K and 48(1) K, respectively.

2-Lithiobenzothiazole reacts with freshly generated [W(CO) 5 (THF)] to give the anionic ylidene complex (1). Treatment of 1 with allyl bromide yields complex [W(CO) 5 (1-allylbenzothiazolin-2- ylidene)] (2) while the reaction in wet CH 2 Cl 2 leads to the formation of a mixture of 2 (major) and [W(CO) 5 (1-H-benzothiazolin-2-ylidene)] (3) (minor). Complex 2 reacts in a transmetallation reaction with [Rh(coe) 2 (μ-Cl)] 2 (coe = cyclooctone) to give the dicarbene complex [Rh(Cl)(η 1 - NHC)(η 2 -NHC)] (NHC = 1-allylbenzothiazolin-2-ylidene) with one carbene ligand coordinated via the C2 carbon atom and the other one coordinating with both the C2 carbon atom and the allyl group.

The title compound was discovered as an impurity phase in many GdCoSi samples. It crystallizes in the hexagonal space group P6 3 /m with a = 11.7787(5) and c = 4.1640(2) Å . Using X-ray powder diffraction, an ordered distribution between Co and Si was found but one site is not fully occupied by Co for steric reasons. Magnetization measurements reveal that Gd 6 Co 1.67 Si 3 exhibits a ferromagnetic transition at TC = 294(2) K, a Curie temperature similar to that reported for pure gadolinium. This magnetic ordering has been confirmed by electrical resistivity investigations.

Na 2 Rb 2 SiO 4 crystallizes in a hitherto unknown A 2 B 2 CX 4 type of structure. The ortho-silicate anions and sodium cations form a three-dimensional structure of connected tetrahedral and trigonalbipyramidal units. The larger rubidium cations complement the cationic part of the structure and display the motif of corrugated hexagonal layers with Rb-Rb distances of less than 400 pm. Single crystal structure data (space group Pbca, Z = 8, a = 983.20(7), b = 1092.26(6), c = 1113.04(8) pm) are given and a comparison to other A 2 B 2 CX 4 -type of structures is presented.

The reaction of dialkylzinc compounds R 2 Zn (R = Me, Et) with N,N-dimethylhydrazine and trimethylsilanol in a 4 : 2 : 2 ratio leads to the formation of tetra(alkylzinc) tris-siloxide monohydrazide aggregates, [(RZn) 4 (NHNMe 2 )(OSiMe 3 ) 3 ] [R = Me (1) and Et (2)]. These compounds are aggregates of mirror symmetry, containing the novel Zn 4 N 2 O 3 core. Both compounds have been characterised by 1 H, 13 C and 29 Si NMR and IR spectroscopy, by mass spectrometry and by elemental analysis, and 2 also by X-ray crystallography. The structure can be derived from a heterocubane, in which one anionic vertex is replaced by an NHNMe 2 group contributing two N atoms to the core constitution. By applying a ratio of hydrazine : silanol of 2 : 1 in a reaction with R 2 Zn (R = Me, Et, iPr), compounds of the general formula [(RZn) 4 (NHNMe 2 ) 2 (OSiMe 3 ) 2 ] [R = Me (3), Et (4), iPr (5)] are obtained. These aggregates contain a Zn 4 N 4 O 2 core. Upon employing a hydrazine : silanol ratio of 5 : 1 in a reaction with diisopropyl zinc, the compound [(iPrZn) 4 (NHNMe 2 ) 3 (OSiMe 3 )] results, containing a Zn 4 N 6 O unit. Compounds 3 - 6 have been characterised by 1 H, 13 C and 29 Si NMR and IR spectroscopy, by mass spectrometry and by elemental analysis. The topologic relationship between the pure hydrazides [(RZn) 4 (NHNMe 2 ) 4 ], the mixed aggregates [(RZn) 4 (NHNMe 2 ) 3 (OR’)], [(RZn) 4 (NHNMe 2 ) 2 (OR’) 2 ] and [(RZn) 4 (NHNMe 2 ) 3 (OR’) 3 ] and the pure alkoxides [(RZn) 4 (OR’) 4 ] is discussed.

The new isotypic intermetallic phases Ba 5 M III 5 M IV (M III = Al, Ga; M IV = Sn, Pb) have been synthesized from stoichiometric amounts of the elements at maximum temperatures of 900 to 1000 ◦C. They crystallize in the hexagonal space group P6̄m2 (Ba 5 Al 5 Sn: a = 605.05(8), c = 1109.0(2) pm, R1 = 0.0137; Ba 5 Ga 5 Sn: a = 599.45(5), c = 1086.00(7) pm, R1 = 0.0485; Ba 5 Al 5 Pb: a = 606.9(2), c = 1112.0(4) pm, R1 = 0.0409 and Ba 5 Ga 5 Pb: a = 601.76(7), c = 1091.51(13) pm, R1 = 0.0295), forming a new structure type. Similar to the Zintl phases Ba 2 M IV (Co 2 Si structure type, orthorhombic, space group Pnma; Ba 2 Sn: a = 861.52(14), b = 569.85(9), c = 1056.9(2) pm, R1 = 0.0217 and Ba 2 Pb: a = 865.12(13), b = 569.1(2), c = 1061.8(2) pm, R1 = 0.0470), these new ternary phases contain isolated M IV atoms (coordinated by 11 Ba atoms). In addition, sheets of 3- and 4-bonded Al/Ga atoms similar to those in Ba 3 Al 5 are present. In accordance with this, a formal subdivision of Ba 5 M III 5 M IV into Ba 3 M III 5 ・ Ba 2 M IV can be performed to describe the observed intergrowth or chemical twinning of two different binary intermetallics to give the new ternary compounds. Beyond structural aspects, also the nature of the chemical bonding (as studied by FP-LAPW calculations) in these new, non-electron precise compounds in the vicinity of the Zintl border can be interpreted in this vein.

The heterocyclic hydrazine derivatives N-aminopyrrole, H 2 N-NC 4 H 4 , and N-aminopiperidine, H 2 N-NC 5 H 10 , reacted with the hydrides H-Al(CMe 3 ) 2 or GaH 3 NMe 2 Et by the release of elemental hydrogen and the formation of the corresponding aluminum and gallium hydrazides. These products are dimerized in the solid state via Al-N-Al or Ga-N-Ga bridges and possess four-membered E 2 N 2 heterocycles with two exocyclic N-N bonds.

Single crystals of Pt 2 Sn 2 Zn 3 , the first ternary compound in the system Pt/Sn/Zn, have been synthesised from the elements. Pt 2 Sn 2 Zn 3 exhibits a new structure type (hP14, P6 3 /mmc, Z = 2, a = 4.3367(5), c = 15.532(3) Å , 402 reflections, 14 variables, R 1 (F) = 0.025, wR 2 (I) = 0.059) with motifs of the binary compounds. One Pt atom has a cubic environment (PtSn 6 Zn 2 ), the second one forms an Edshammer polyhedron (PtSn 2 Zn 9 ). Pt 2 Sn 2 Zn 3 is one of the few examples of a ternary Sn/Zn compound of a transition metal.

The title compound was prepared by the reaction of [Me 4 N] 2 WOS 3 with AgCN in MeCN at room temperature and slow crystallisation in the refrigerator. It was characterized by IR and mass spectroscopy. It crystallizes in the orthorhombic space group Pnma (No. 62) with unit cell dimensions a = 19.648(7), b = 27.878(12), c = 11.494(3) Å , Z = 8. The crystal structure was determined from single crystal diffractometer data (Mo-Kα radiation) and refined to R = 0.077. The structure is composed of mixed double layers containing the linear trinuclear anion [(WOS 3 ) 2 Ag] 3− and cations separated by a layer formed by cations and solvating acetonitrile molecules.

The formation of Au 3 Sn heteroclusters completes the homologous series of M 3 Sn clusters observed for transition metal main-group polyphosphides. Au 3 SnCuP 10 is cubic, space group F4̅3̅m (No. 216) with lattice parameter a = 10.3953(5) Å . The structure refinement yielded R1 = 0.0353 and wR2 = 0.0726 for 154 F 2 values and 13 variables. Disordered Au 3 Sn heteroclusters occupy all octahedral, and adamantane like P 10 cages one half of the tetrahedral voids of a face-centred cubic ( fcc) arrangement of copper. Ordered and orientationally disordered Au 3 Sn heteroclusters have been observed for Au 3 SnP 7 , embedded in a 1 ∞ [P 7 ] polyphosphide unit formed by six-membered phosphorus rings in chair conformation which are linked by a P-bridge. Au 3 SnP 7 is monoclinic, space group P2 1 /m (No. 11) with lattice parameters of a = 6.219(2), b = 10.836(2), c = 6.318(2) Å , β = 108.65(2)°, V = 403.4(2) Å 3 , R1 = 0.0412 and wR2 = 0.0745, 1261 F 2 values and 56 variables. Au 3 SnP 7 with disordered Au 3 Sn clusters has slightly larger lattice parameters of a = 6.343(3), b = 10.955(3), c = 6.372(3) Å , β = 108.63(2)°, V = 419.6(2) Å 3 , R1 = 0.0324 and wR2 = 0.0691, 1131 F 2 values and 58 variables.

The complex [Rh(CO)Cl{Me 2 PC(Me)=C(Me)BMe 2 } 2 ] (5) has been prepared again in order to prove its structure with weak bonding interactions between the basic rhodium centre and the Lewisacidic Me 2 B group of the donor/acceptor ligand Me 2 PC(Me)=C(Me)BMe 2 (1). For further investigations additional ligands with P-donor and B-acceptor centres, e. g. Ph 2 PC(Ph)=C(Ph)BPh 2 (2), B(OCH 2 PMe 2 ) 3 (3), and B(CH 2 CH 2 PMe 2 ) 3 (4), have been prepared and the coordinating properties have been studied by reactions of 1 and 4 with [(π-C 5 Me 5 )Rh(CO) 2 ] and Pd(PPh 3 ) 4 , respectively. Because single crystals of the products [(π-C 5 Me 5 )Rh(CO)Me 2 PC(Me)=C(Me)BMe 2 ] (6), [(π-C 5 Me 5 )Rh(CO){Me 2 PC(Me)=C(Me)BMe 2 } 2 ] (7) as well as [Pd{B(CH 2 CH 2 PMe 2 ) 3 }] (8) or [(Ph 3 P)Pd{B(CH 2 CH 2 PMe 2 ) 3 }] (9) could not be generated, quantum chemical calculations have been used to elucidate the coordination geometry expected for 5, 8 and 9. The calculations support the structure of 5 within the expected limitations of the experimental and theoretical methods and - in spite of the extremely soft coordination sphere of 8 and 9 - are in accord with spectroscopic results for the cage structures.

The reaction of the cycloheptatrienyl-toluene sandwich complex [(η 7 -C 7 H 7 )Mo(η 6 - C 6 H 5 Me)]BF 4 with tricyclohexylphosphine in acetonitrile furnishes the cationic half-sandwich cycloheptatrienyl complex {(η 7 -C 7 H 7 )Mo[P(C 6 H 11 ) 3 ](CH 3 CN) 2 }BF 4 (1). Treatment of 1 with NaBH 4 in ethanol results in the formation of the tetrahydroborate complex {(η 7 -C 7 H 7 )Mo(η 2 - BH 4 )[P(cyclo-C 6 H 11 ) 3 ]} (2), in which the borohydride ligand is coordinated to the molybdenum atom through two three-center, two-electron bonds. The complex is stable in ethanol and water. The expected formation of a metal trihydride of the type {(η 7 -C 7 H 7 )MoH 3 [P(cyclo-C 6 H 11 ) 3 ]} as a hydrolysis product could not be observed. Since this behaviour differs from the reactivity reported for related cyclopentadienyl-ruthenium complexes, a comparative computational study on the model complexes [(η 5 -C 5 Me 5 )RuH 3 (PMe 3 )] (4) and [(η 7 -C 7 H 7 )MoH 3 (PMe 3 )] (5) was performed revealing that the classical trihydride form [MH 3 ] represents the global minimum for the ruthenium complex 4, whereas the dihydrogen-hydride form [MH(η 2 -H 2 )] is more stable for the molybdenum counterpart.

The compounds Eu 2 Rh 3 Ga 9 and Eu 2 Ir 3 Ga 9 were synthesized by melting the elements in sealed tantalum tubes with subsequent annealing at 600 °C. Both gallides are isotypic with Y 2 Co 3 Ga 9 (space group Cmcm, Pearson symbol oC56, Z = 4) as evidenced by single crystal structure analysis: a = 12.9902(6), b = 7.6141(4), c = 9.7433(5) Å , RF = 0.025, 617 structure factors, 42 variable parameters for Eu 2 Rh 3 Ga 9 , and a = 13.0371(7), b = 7.6017(4), c = 9.6972(6) Å , RF = 0.032, 645 reflections, 42 variables for Eu 2 Ir 3 Ga 9 . Magnetic susceptibility measurements as well as X-ray absorption spectra indicate the 4f 7 electronic configuration of europium (Eu 2+ ) with significant admixture of the 4f 6 state in both compounds.

Single crystals of Cs 2 K 2 [Pt 12 O 8 (SO 4 ) 12 ] (R3̄, Z = 3, a = 1198.9(3), c = 2768.9(9) pm, R all = 0.1154) were obtained by the reaction of Cs 2 [Pt(NO 2 ) 4 ], K 2 [Pt(NO 2 ) 4 ] and conc. sulfuric acid at 400 °C in a sealed glass ampoule. The compound contains the cluster anion [Pt 12 O 8 (SO 4 ) 12 ] 4− . It consists of six Pt 2 6+ dumbbell shaped cations that are linked by eight oxide ions and twelve sulfate anions to form a distorted Pt 12 icosahedron. The arrangement of the cluster anions in the crystal structure provides two voids for the cations. The larger one is occupied by the Cs + ions while the K + ions reside in the smaller one. For the Cs + ions the coordination number is 15 while the K + ions have a coordination number of 13.

The total conductivity of the solid solutions (Ce 1−x Zr x )0.8Gd 0.2 O 1.9 and (Ce 1−x Zr x ) 0.8 Y 0.2 O 1.9 was measured in air as a function of temperature (T = 300 °C- 600 °C) and composition (x = 0.0 - 0.9). A deep minimum of the bulk ionic conductivity was found for equal fractions of ceria and zirconia. It indicates enhanced defect association and ordering of the oxygen vacancies around x = 0.5. X-ray analysis (Guinier technique) showed the diffraction pattern of the cubic fluorite structure for all investigated compositions 0 < x < 1. The lattice parameter decreased linearly with increasing zirconia content x.