Band 235, Heft 3

The ternary rare earth gallides RE RhGa 3 with RE  = La, Ce and Pr were synthesized by arc-melting and subsequent annealing in a muffle furnace. The gallides were characterized through Guinier powder patterns and the structure of LaRhGa 3 was refined from single-crystal X-ray diffraction data: SrPdGa 3 type, Cmcm , a  = 639.2(2), b  = 1030.9(2), c  = 589.3(2) pm, w R2 = 0.0964, 416 F 2 values and 19 variables. The rhodium and gallium atoms build up a three-dimensional polyanionic network [RhGa 3 ] which is stabilized through Rh–Ga (245–251 pm) and Ga–Ga (267–295 pm) bonds and filled by the lanthanum atoms. The crystal chemical relationship with the structures of LaRh 2 Ge 2 (ThCr 2 Si 2 type), LaRh 2 Ga 2 (CaBe 2 Ge 2 type) and LaRhGe 3 (BaNiSn 3 type) is discussed.

Synthesis, structural characterization and chemical bonding peculiarities of two new quaternary selenides of the Tl 4 Sb 8 Sn 5 Se 24 and Tl 5 Sb 2 Sn 4 Se 14−x (x = 0.5) are reported. The crystal structures of these compounds were determined by single crystal X-ray diffraction analysis. The Tl 4 Sb 8 Sn 5 Se 24 phase is a new structure type and crystallizes in the triclinic P  1̅ space group ( a =  7.9061(13) Å, b =  13.9035(16) Å, c =  21.4665(17) Å, α = 80.058(8)°, β = 84.727(10)°, γ = 73.542(12)°, w R 2  = 0.0258, 8200 F 2 values, 373 variables). The Tl 5 Sb 2 Sn 4 Se 14−x (x = 0.5) phase represents a new structure type with a tetragonal unit cell ( P  4 /mbm , a =  8.1570(10) Å, c =  21.946(3) Å, w R 2  = 0.0346, 1953 F 2 values, 44 variables). Crystallographic analysis together with linear muffin-tin orbital band structure calculations reveals that both structures we conform to the concept of Zintl-Klemm and exhibit semiconductor properties.

Structural and packing features of three new amidophosphoric acid esters having a common part X P(O)[OCH 2 C(CH 3 ) 2 CH 2 O], with X  = [(CH 3 ) 3 CNH] ( 1 ), [(CH 3 ) 2 HCNH] ( 2 ) and [C 6 H 11 (CH 3 )N] ( 3 ), are investigated by single crystal X-ray diffraction. The results illustrate that the compounds 1 and 3 crystallize with one independent molecule in the asymmetric unit; whereas, for 2 , the compound crystallizes with three independent molecules in the asymmetric unit. The crystal structures are mostly stabilized via tri-furcated hydrogen bond interactions (C–H · · ·) 2 (N–H · · ·)O=P in 1 and (C–H · · ·) 3 O=P in 3 , while the stability is given by bi-furcated hydrogen bond interactions (C–H · · ·)(N–H · · ·)O=P in 2 . For a better understanding of the nature, strength and energetics associated with the formation of the quoted multi-center hydrogen bond interactions, the Natural Bond Order (NBO) method from Density Functional Theory (DFT) and a topological analysis by means of Atoms In Molecules (AIM) and Hirshfeld surface procedures were performed. These studies reveal that the studied multi-center hydrogen bond interactions of the type O · · · H are favoured in the crystal packing displaying enrichment ratios larger than unity. The detailed nature of the different interactions in these multi-center interactions is studied for the first time in such compounds. It is shown that the N–H · · · O interaction is rather non-covalent closed-shell whereas the C–H · · · O interaction is more van der Waals closed-shell. Stronger hydrogen bond interactions are observed for a lower multiple H-atom acceptor oxygen in three-center hydrogen bond interactions (C–H · · ·)(N–H · · ·)O=P of 2 than for four-center interactions in 1 [i.e. (C–H · · ·) 2 (N–H · · ·)O=P] and 3 [i.e. (C–H · · ·) 3 O=P]. The better H-atom acceptability of the O atom of P=O compared with the esteric O atom is explained by the richer s -character of the hybrid orbital of the O atom acceptor of P=O coupled with enhance of the polarization and charge. The obtained results are also confirmed by Molecular Electrostatic Potential (MEP).

The title compound 1-(2-chlorophenyl)-3,3-bis(methylthio)prop-2-en-1-one ( 1 ) have been synthesized, crystallized and characterized using FT-IR, 1 H NMR, 13 C NMR, LCMS and confirmed by single crystal X-ray diffraction method. In addition, the intermolecular interactions in the crystal structure are analyzed using Hirshfeld surfaces computational method. The ( 1 ) crystallizes in a monoclinic crystal system (space group P  2 1/ c ) with cell parameters a  = 17.0132(9) Å, b  = 8.6521(4) Å, c  = 8.2815(7) Å, β  = 95.512(6) ° and Z  = 4. Intermolecular hydrogen bonds/interactions of the type C · · · H · · · O, C–H · · · S, C–H · · · Cg and C–Cl · · · Cg stabilize the crystal structure. The intermolecular interactions responsible for crystal packing are analyzed using Hirshfeld surfaces computational method, 2D finger print plots, electrostatic potential surfaces, toplogy surfaces [curvedness ( C ) and shape index ( S ), enrichment ratio ( E ) and 3D energy frameworks]. In addition the dielectric studies were performed for the title molecule. The crystal structure database (CSD) analysis was carried out for structural conformation and crystal packing confirmation. Overall structural studies confirmed that the intermolecular interactions of the type S · · · S chalocogen bonds are involved in crystal packing in addition to the C11–H11 · · · O1, C10–H10B · · · O1, two C10–H10 · · · S1, C4–H11 · · · Cg1 and C1–Cl1 · · · Cg1 interactions.

Experimental investigations of crystallization in a family of uranyl triacetate compounds with Na, K, Rb and Cs were performed. The crystal structures of two novel Cs- and Rb-bearing tri(acetato)uranylates were solved, and the content of H 2 O molecules in the crystal structure of K-bearing uranyl triacetate was refined. Synthesized compounds were analyzed using IR spectroscopy and single-crystal X-ray diffraction. Crystal chemical analysis of the M [(UO 2 )(CH 3 COO) 3 ](H 2 O) n family ( M  = Na, K, Rb, Cs; n  = 0–1.0) reveals the sequence of structural transformations depending on the size of alkali cation resulting in the symmetry reduction from cubic P  2 1 3 (for Na), through tetragonal I  4 1 / a (for K and Rb) to triclinic P  1̅ space groups (for Cs), which is in accordance with the principle of morphotropism, suggested by Paul von Groth, founder of the Zeitschrift für Krystallographie journal, in 1870.