Band 74, Heft 5

The salt [Rh(III)(phpy) 2 (dtoxa)]Cl with phpy = 2-(2-pyridyl)phenyl anion and dtoxa = dithiooxamide has been characterized by its crystal structure and its electronic spectra. Since Rh(III) is rather redox-inert, the lowest-energy excited state of the complex cation is of the IL (dtoxa) type. In the solid state as well as in solution the complex is luminescent and displays a dtoxa IL phosphorescence at λ max  = 607 nm with φ ϕ  = 10 −3 and τ  = 3.7 ns in CH 2 Cl 2 .

A new Mn(II) complex [Mn 2 (L)(H 2 O) 3 ] · (H 2 O) 4.8 ( 1 ) was synthesized via the hydrothermal reaction of MnCl 2  · 4H 2 O with N 4 , N 4′ -di(5-isophthalyl)biphenyl-4,4′-dicarboxamide (H 4 L). Complex 1 is characterized by single-crystal and powder X-ray diffraction, infrared   spectroscopy, and elemental and thermogravimetric analyses. 1 exhibits a uninodal 5-connected 3D bnn framework structure with (4 6 .6 4 ) topology. The magnetic properties of 1 were investigated.

The hydrothermal reaction of Co(II) nitrate with 5-(pyridin-4-yl)isophthalic acid (H 2 L) yields a new complex [Co(L)(H 2 O) 5 ] · 4(H 2 O) ( 1 ). When 4,4′-bipyridine (bpy) as auxiliary ligand and Zn(II) nitrate were used in the same reaction system, [Zn(L)(bpy)] · 0.5(DMF) · 0.5(H 2 O) ( 2 ) could be obtained. Complexes 1 and 2 have been characterized by single-crystal X-ray diffraction, infrared spectroscopy, and elemental and thermogravimetric analyses. Complex 1 displays a discrete mononuclear structure, whereas 2 exhibits a binodal (3,5)-connected twofold interpenetrated three-dimensional hms framework architecture with (6 3 )(6 9 ,8) topology. The fluorescence properties of 2 were also investigated.

33 S nuclear quadrupole resonance (NQR) frequencies of 33 S-enriched S -4-phenyl 4-toluenethiosulfonate were observed in the range of 22.96–23.31 MHz at temperatures between 110 and 300 K. A single sharp signal was observed at all the temperatures. The two-dimensional (2D) nutation echo method was applied at 150 K, providing the 33 S electric field gradient (EFG) tensor information, the quadrupolar coupling constant, C Q , of 42.3 MHz and the asymmetry parameter, η Q , of 0.80(9). Quantum chemical calculations were performed to obtain the 33 S EFG tensor orientations with respect to the molecular frame.

Natural lead dioxide samples ( β modification) from Cap Garonne, Mine du Pradet, France and Mount Trevasco, Italy were studied by single crystal X-ray and electron diffraction, clearly manifesting the rutile-type structure. A needle from the Mount Trevasco sample was investigated on a single crystal diffractometer: P 4 2 / mnm , a  = 495.81(10), c  = 338.66(7) pm, wR  = 0.0513, 117 F 2 values (all data) and nine variables (293 K data). An additional data set at T  = 90 K gave no hint for structural distortions.

Cubic C -type samarium sesquioxide, Sm 2 O 3 , was prepared by thermal decomposition of samarium carbonate. Its crystal structure was refined based on neutron powder diffraction data [space group Ia 3̅, a  = 1092.77(6) pm] in order to accurately determine the oxygen atom positions. Isotopically enriched 154 Sm 2 O 3 was used for the neutron diffraction work because of the enormous absorption cross section of the natural isotopic mixtures for thermal neutrons. Crystal structure refinements by the Rietveld technique confirm the cubic bixbyite type and yield structure data of high accuracy. Interatomic distances between Sm1 (Wyckoff site 8 a ) and oxygen are 6 × 235.0(2) pm, and between Sm2 (Wyckoff site 24 d ) and oxygen 2 × 231.6(2) pm, 2 × 233.7(2) pm, 2 × 240.2(2) pm with a weighted average of d ̅(Sm–O) = 235.1(2) pm.

Phase-pure samples of the antimonides PrPdSb and NdPdSb were prepared by arc-melting pieces of the elements and subsequent annealing. The samples were investigated by powder and single crystal X-ray diffraction: NdPtSb type, space group P 6 3 mc , a  = 458.70(5), c  = 780.55(6) pm, wR 2 = 0.0272, 244 F 2 values, 11 variable parameters for PrPdSb and a  = 458.18(4), c  = 771.25(6) pm, wR 2 = 0.0317, 229 F 2 values, 11 variable parameters for NdPdSb. The palladium and antimony atoms form slightly puckered Pd 3 Sb 3 hexagons which are rotated by 60° in every other layer. The rare earth ( RE ) atoms are coordinated by two Pd 3 Sb 3 hexagons with the RE –Pd shorter than the RE –Sb contacts. The 121 Sb Mössbauer spectra at T  = 5 K confirm the antimonide character with isomer shifts of −7.55 (PrPdSb) and −7.47 mm · s −1 (NdPdSb). In agreement with the crystal structures, each spectrum could be fitted with one quadrupole split signal.

Rod-shaped single crystals of Sr 4 Pt 10 In 21 were prepared from the elements in glassy-carbon crucibles in a high-frequency furnace. The structure of Sr 4 Pt 10 In 21 was refined from single-crystal X-ray diffractometer data: C 2/ m , Ho 4 Ni 10 Ga 21 type, a  = 2322.62(7), b  = 450.27(2), c  = 1958.09(7) pm, β  = 133.191(3)°, wR  = 0.0464, 3200 F 2 values and 107 variables. The three-dimensional [Pt 10 In 21 ] δ− polyanionic network is stabilized through substantial Pt–In (269–313 pm Pt–In) and In–In (294–362 pm In–In) bonding. All platinum atoms have slightly distorted tri-capped trigonal prismatic coordination and the two crystallographically independent strontium atoms are located in penta-capped pentagonal prisms.

Eu 2 Mg 4 Si 3  ≡ (2Eu 2+ )(4Mg 2+ )(3Si 4− ) is an electron-precise Zintl phase. Its Hf 2 Co 4 P 3 -type structure contains three crystallographically independent europium sites. The divalent state of europium was manifested through 151 Eu Mössbauer spectroscopy. In the paramagnetic regime ( T  = 78 K) the isomer shifts range from −9.16 to −11.29 mm s −1 . Eu 2 Mg 4 Si 3 shows complex magnetic hyperfine field splitting at T  = 5.7 K with a superposition of three subspectra with magnetic hyperfine fields of 5.4 (Eu2), 20.4 (Eu1) and 22.4 (Eu3) T.

The synthesis and structural characterization of the new olefinic complex [Rh( η 5 -C 5 H 5 )(coe)(P t Bu 2 H)] ( 2 , coe =  cis -cyclooctene) is reported. The title compound was easily prepared in good yield by a thermolytic approach using [Rh( η 5 -C 5 H 5 )(coe) 2 ] ( 1 ) and the secondary phosphane in toluene under reflux conditions. The compound 2 has been characterized by NMR spectroscopy and microanalysis. Single crystals of 2 were grown from n -hexane and the molecular structure has been established by X-ray diffraction.