ALBERT

Description: . Black platelets of Bi 39.67(7) Ru 2 Br 35.0(2) were crystallized from a melt of Bi, BiBr 3 , and Ru. In the tetragonal crystal structure [ P 4/ mbm , a = 1311.92(6) pm, c = 3018.2(4) pm at 155(5) K], cluster cations [(Bi 8 2+ )Ru 2+ (Bi 8 2+ )] are embedded in a matrix of disordered bromido-bismuthate(III) groups. A thorough analysis of the disorder in the anionic part enabled the unambiguous assignment of the cluster charge. The η 4 -coordination of the two Bi 8 2+ square antiprisms to the Ru II atom in the sandwich complex resembles the bonding of Bi 5 + and Bi 8 2+ in the clusters [(Bi 5 + )Ru + (Bi 4 Br 4 )Ru + (Bi 5 + )] and [(Bi 8 2+ )Ru + (Bi 4 Br 4 )Ru + (Bi 5 + )] as well as of Bi 4 2– in 1 ∞ [(Bi 4 2– )Ru + (Bi 4 Br 4 )Ru + ]. By combining crystal chemical considerations for all mentioned compounds and using quantum chemical calculations, a common bonding scheme for the coordination compounds of bismuth polycations and polyanions was established. The η 4 -coordinating bismuth polycations and polyanions act as six electron donors, comparable to nido -carborane ligands, Zintl anions E 9 4– and E 5 6– ( E = Si to Pb), cyclopentadienyl ligands, or the cyclobutadiene dianion. The electron count for the transition metal is 18 in all finite clusters.

Description: The capability of Yersinia ruckeri to survive in the aquatic systems reflects its adaptation (most importantly through the alteration of membrane permeability) to the unfavorable environments. The nonspecific porins are a key factor contributing to the permeability. Here we studied the influence of the stimuli, such as temperature, osmolarity, and oxygen availability on regulation of Y. ruckeri porins. Using qRT-PCR and SDS-PAGE methods we found that major porins are tightly controlled by temperature. Hyperosmosis did not repress OmpF production. The limitation of oxygen availability led to decreased expression of both major porins and increased transcription of the minor porin OmpY. Regulation of the porin balance in Y. ruckeri , in spite of some similarities, diverges from that system in Escherichia coli . The changes in porin regulation can be adapted in Y. ruckeri in a species-specific manner determined by its aquatic habitats. The capability of Yersinia ruckeri to survive in the aquatic systems reflects its adaptation to the unfavorable environments. The nonspecific porins are a key factor contributing to the permeability. We studied the influence of the stimuli, such as temperature, osmolarity, and oxygen availability on regulation of Y. ruckeri porins.

Description: Melting reactions of copper, CuI, selenium, and Bi 2 Se 3 yielded black, shiny needles of Cu 4 BiSe 4 I = Cu 4 BiSe 2 (Se 2 )I. The compound decomposes peritectically above 635(5) K and crystallizes in the orthorhombic space group Pnma with a = 960.1(1) pm, b = 413.16(3) pm, and c = 2274.7(2) pm ( T = 293(2) K). In the crystal structure, strands [BiSeSe 2/2 (Se 2 ) 2/2 ] 3– run along [010]. Therein, the bismuth(III) cation is coordinated by five selenium atoms, which form a square pyramid. The copper(I) cations are coordinated tetrahedrally by selenide, diselenide and iodide ions. Edge-sharing of these tetrahedra results in zigzag chains of copper cations with short distances of 262.7(4) pm. Enhanced dispersion of the 3 d bands, the Crystal Orbital Hamilton Populations (COHP), and disynaptic ELI-D basins indicate weakly attractive d 10 ··· d 10 interactions between the copper cations. The semiconducting properties and the calculated electronic band structure suggest an electron-precise compound. In copper-deficient Cu 3.824(8) BiSe 4 I, the Cu···Cu distances are 5 pm shorter, and Raman spectroscopy indicates the presence of diselenide(1–) radical anions besides the diselenide(2–) groups. As a result, in Cu 3.824(8) BiSe 4 I, selenium coexists in the oxidations states –II, –I, and –0.5.

Description: The reaction of antimony and selenium in the Lewis-acidic ionic liquid 1-butyl-3-methyl-imidazolium tetrachloridoaluminate, [BMIm]Cl · 4.7AlCl 3 , yielded dark-red crystals of [Sb 2 Se 2 ]AlCl 4 . The formation starts above 160 °C; at about 190 °C, irreversible decomposition takes place. The compound crystallizes in the triclinic space group P with a = 919.39(2) pm, b = 1137.92(3) pm, c = 1152.30(3) pm, α = 68.047(1)°, β = 78.115(1)°, γ = 72.530(1)°, and Z = 4. The structure is similar to that of [Sb 2 Te 2 ]AlCl 4 but has only half the number of crystallographically independent atoms. Polycationic chains 1 ∞ [Sb 2 Se 2 ] + form a pseudo-hexagonal arrangement along [011 ], which is interlaced by tetrahedral AlCl 4 – groups. The catena -heteropolycation 1 ∞ [Sb 2 Se 2 ] + is a sequence of three different four-membered [Sb 2 Se 2 ] rings. The chemical bonding scheme, established from the topological analysis of the real-space bonding indicator ELI-D, includes significantly polar covalent bonding in four-member rings within the polycation. The rings are connected into an infinite chain by homonuclear non-polar Sb–Sb bonds and highly polar Sb–Se bonds. Half of the selenium atoms are three-bonded.

Description: Black, shiny crystals of the molecular cluster compounds (Te 10 )[ M (Te X 4 )(Te X 3 )] 2 ( M / X = Rh/Cl ( 1 ), Ir/Br ( 2 )), (Te 10 )[Ru(TeI 4 )(TeI 2 )] 2 ( 3 ), (Te 10 )[ M (TeI 4 )(TeI 2 )] 2 (TeI 4 )(Te 2 I 2 ) ( M = Rh ( 4 ), Ir ( 5 )) as well as the one-dimensional cluster polymer (Te 10 I 2 )[Ir(TeI 4 )] 2 (Te 4 )I 2 ( 6 ) were synthesized by melting reactions of an electron-rich transition metal M ( M = Ru, Rh, Ir) with tellurium and Te X 4 ( X = Cl, Br, I). X-ray diffraction on single-crystals revealed that the compounds crystallize in the triclinic space group type P . 4 and 5 show [3+1]-dimensional modulations of their structures. All compounds contain binuclear complexes with central μ-η 4 :η 4 -bridging Te 10 units and terminal halogenidotellurate(II) groups. Each of the transition metal cations is in a slightly distorted octahedral coordination by six tellurium atoms; the two [ M Te 6 ] octahedra share a common edge. With the tellurium atoms acting as electron-pair donors, the 18 electron rule is fulfilled for the electrophilic M atoms. The central tricyclo [5.1.1.1 3, 5 ]-decatellurium molecule consists of two ecliptically stacked Te 4 rings, which are linked through two tellurium atoms. The symmetric or asymmetric 3c4e bonds along these almost linear bridges are in analogy to polyanionic forms of tellurium, while the tricyclic conformation is stabilized by the strong bonding to the transition-metal cations. Multi-center bonding (3c4e) is also present in the terminal square [Te +II X 4 ] 2– and the T-shaped [Te +II X 3 ] – groups. The crystal structures of 4 and 5 are organized in layers of (Te 10 )[ M (TeI 4 )(TeI 2 )] 2 n+ clusters ( n ≤ 2) that are quite robust upon oxidation or reduction as shown by molecular calculations. These clusters alternate with incommensurately modulated layers that probably consist of TeI 4 2– anions and a previously unknown Te 2 I 2 molecule. The uncertainty arises primarily from equal scattering powers of I and Te atoms as well as from the known flexibility of the electron count of the Te 10 unit. In 6 , neutral Te 4 rings concatenate (Te 10 I 2 )[Ir(TeI 4 )] 2 clusters into chains, which run parallel to the a axis.

Description: . The reaction of the electrophilic transition metal iridium with tellurium, indium, and bromine resulted in black, shiny crystals with the composition [Ir 2 Te 14 Br 12 ] 2 (InBr 4 ) 2 . X-ray diffraction on single-crystals revealed a triclinic structure (space group P ) that contains two crystallographically distinct, centrosymmetric clusters, (Te 10 )[Ir(TeBr 3 ) 2 ] 2 + and (Te 10 )[Ir(TeBr 4 )(TeBr 2 )] 2 + , as well as two tetrahedral InBr 4 – anions per unit cell. The center of the positively charged cluster is a Te 10 · – radical anion. This biconvex tricyclo [5.1.1.1 3, 5 ] unit consists of two angulated Te 4 rings that are linked by two almost linear μ-Te bridges. The radical causes an intense single ESR signal at g = 1.999. Molecular DFT-calculations show that the unpaired electron populates an orbital of the Te 10 -unit. Computational variation of the number of electrons causes noticeable variations in the Te–Te distances, providing strong evidence for the Te 10 · – radical. The decatellurium unit coordinates two iridium(III) cations as a bridging bis-tetradentate ligand. Two terminal bromidotellurate(II) groups complete the slightly distorted octahedral coordination of each transition metal atom. The two [IrTe 6 ] polyhedra share a common edge. The constitutions of the terminal ligands differ, including only TeBr 3 – anions in one type of clusters, but a combination of TeBr 4 2– and TeBr 2 groups in the other. The coordinating tellurium atoms of the central Te 10 · – and of the terminal groups act as electron pair donors, thereby fulfilling the 18-electron-rule for the iridium(III) cations.

Description: . Uniform nanocrystals of the intermetallic compounds Bi 2 Ir (diameter ≥ 50 nm) and Bi 3 Ni (typical size 200 × 600 nm) were obtained by a microwave-assisted polyol process at 240 °C. The method was also applied to the spatially confined reaction environment in the microporous exo -template SBA-15 resulting in Bi 3 Ni particles of about 6 nm. Non-crystalline bundles of parallel Bi 3 Ni nanofibres that have an individual diameter of less than 1 nm were obtained by reductive pseudomorphosis of the subiodide Bi 12 Ni 4 I 3 at room temperature. Magnetic susceptibility measurements demonstrate coexistence of ferromagnetism and superconductivity in a single phase for the nanostructured Bi 3 Ni materials. Curie temperature, coercive field, remnant magnetization, saturation moment, diamagnetic screening, and critical field vary with particle size. The crystal structure of Bi 2 Ir was determined by Rietveld refinement of powder X-ray diffraction data. Bi 2 Ir crystallizes in the monoclinic arsenopyrite type (space group P 2 1 / c ), a superstructure of the markasite type, with a = 690.11(1), b = 678.85(1), c = 696.17(1) pm, and β = 116.454(1)°. In contrast to most of the other phases of this type, the Bi 2 Ir is not a diamagnetic semiconductor but a weakly paramagnetic semimetal. Conductivity measurements down to 4 K and magnetization measurements in a field of μ 0 H = 10 mT down to 1.8 K give no evidence for a transition into the superconducting state. Bonding analysis shows prevailing contribution of Bi–Bi interactions to the conduction, whereas Bi–Ir bonding is mostly covalent and localized.

Description: The reaction of selenium and NbCl 5 with arsenic in the Lewis-acidic ionic liquid BMImCl · 4.8AlCl 3 at 100 °C yielded dark-red block-shaped crystals of Nb 2 Se 4 (AlCl 4 ) 4 , which immediately decompose when exposed to humid air. Arsenic takes the part of the reducing agent for niobium as well as selenium. The crystal structure was described in the monoclinic space group P 2 1 / n (no. 14) with a = 898.0(1) pm, b = 991.3(1) pm, c = 1629.1(2) pm, and β = 92.43(1)° at 296(1) K. The unit cell contains two C 2h symmetric Nb 2 (Se 2 ) 2 (AlCl 4 ) 4 molecules. The latter consist of a central rectangular bipyramid [Nb 2 (Se 2 ) 2 ] 4+ and four η 2 -coordinating AlCl 4 – tetrahedra. Diamagentism of the compound and DFT-based real-space bonding analysis imply a chemical bond between the niobium(IV) cations, which are 292.2(2) pm apart. Nb 2 Se 4 (AlCl 4 ) 4 can be interpreted as the AlCl 3 adduct of NbSe 2 Cl 2 .

Description: The bimetallic subsulfide Bi 8 Ni 8 S was synthesized by reduction of Bi 8 Ni 8 SI 2 with n- BuLi. Bi 8 Ni 8 S is metastable and decomposes exothermically at about 180 °C. In a pseudomorphosis, the shiny black crystals of the precursor were preserved, while the iodide ions were extracted and the pre-formed [Bi 8 Ni 8 S] fragments rearranged into a pseudo-hexagonal rod packing [space group Pbam , a = 1750.14(7) pm, b = 1007.7(2) pm, c = 419.6(3) pm]. The rods have an effective diameter of about 1 nm and consist of an outer octagonal tube of bismuth atoms and an inner octagonal tube of nickel atoms. This arrangement markedly resembles the columnar Ta 4 Te 4 Si structure type. The difference comes with the disulfide groups that reside on the central axis. Interatomic distances inside the rods are almost not affected by the reduction, and thus the electronic band structure is not much altered. Yet, the additional electrons raise the Fermi level into a local maximum of the density of states and occupy predominantly antibonding Ni–Ni and S–S states. The dominant Bi–Ni multicenter bonding is accompanied by localized two-center bonds between nickel atoms. The charges of the nickel atoms as well as ELI-D basin populations of Ni–Ni and Ni–Bi bonds change considerably, indicating that the tube is (un)charging quite flexibly and acts as an electron reservoir. In contrast to the iodide precursor, the weak Pauli paramagnetism of Bi 8 Ni 8 S is slightly enhanced and spin correlations are observed below 20 K.

Description: Black Cu 2 Bi 2 S 3 (AlCl 4 ) 2 and orange Ag 2 Bi 2 S 3 (AlCl 4 ) 2 were synthesized by solvent-free reaction (polycrystalline powders) as well as in Lewis-acidic ionic liquids (crystals) at temperatures of 200 °C or lower. X-ray diffraction on single-crystals of Cu 2 Bi 2 S 3 (AlCl 4 ) 2 revealed two centrosymmetric polytypes: a rhombohedral one, space group R c [ a = 658.02(3) pm, c = 6794.3(3) pm], with six formula units in the unit cell (6R polytype), and a hexagonal one, space group P 6 3 / m [ a = 658.71(6) pm, c = 2265.5(3) pm], with two formula units (2H polytype). Ag 2 Bi 2 S 3 (AlCl 4 ) 2 is homeotypic and crystallizes in the acentric hexagonal space group P 2 c with a = 691.65(3) pm, c = 2207.86(9) pm, and two formula units per unit cell (2H′ polytype). All structures consist of 2 ∞ [( M + ) 2 Bi 2 S 3 ] layers ( M = Cu, Ag) separated by double layers of AlCl 4 – tetrahedra and differ mainly in their stacking sequences and the orientation of the AlCl 4 – groups. The sulfidometalate layer is a honeycomb-like network with M + and S 2– ions in plane, whereas pairs of Bi 3+ cations occupy positions above and below the plane. The analysis of chemical bonding reveals strong covalent two-center two-electron bonds in the five-atomic bipyramidal Bi 2 S 3 unit ( D 3 h symmetry) and covalent bonding with much higher ionic component to the coin metal cations. The DFT-optimized shape of an isolated hypothetical Bi 2 S 3 molecule differs only marginally from that in the layer. Hence, the compounds might be interpreted as Bi 2 S 3 molecules embedded in M AlCl 4 salts. Optical bandgaps of 1.6 eV ( M = Cu) and 2.2 eV ( M = Ag) were deduced from diffuse reflectance measurements. DFT-based quantum chemical calculations indicate direct bandgaps of the same magnitude.