Band 80, Heft 9-10

Seven new organoammonium 1,3-dimethylviolurates [R 1 R 2 R 3 NH][1,3-Me 2 Vio] R 1 = R 2 = H, R 3  =  t Bu ( 3 ), R 3 = Cy (cyclohexyl) ( 4 ), R 3  = Ad (adamantyl) ( 5 ), R 3 = C 6 H 2 Me 2 -4,5-NH 2 -2 ( 6 ); R 1  = H, R 2  = R 3  = Et ( 7 ), i Pr ( 8 ); R 1 = H, R 2  + R 3  = (–CH 2 –) 4 ( 9 ) have been prepared by treatment of 1,3-dimethylvioluric acid ( 2 , = HMe 2 Vio) with different primary and secondary amines. All violurate salts form bright blue or red/purple, nicely crystalline solids. The compounds have been characterized by their solid-state IR and solution NMR ( 1 H, 13 C) and UV-spectroscopic data as well as elemental analyses. Structure determinations by single-crystal X-ray diffraction of compounds 4 , 7 and 9 revealed supramolecular self-assembly into different one-dimensional substructures through cation–anion N–H⋯N and N–H⋯O hydrogen bonds. In addition, the molecular and crystal structure of anhydrous 1,3-dimethylvioluric acid ( 2 ) has also been determined.

The crystal structure of the phosphide Ta 0.88(1) Fe 1.12(1) P has been determined from X-ray powder diffraction data: full-profile refinement, orthorhombic space group Pnma , a  = 6.1036(2) Å, b  = 3.5774(1) Å, c  = 6.9742(2) Å, R I  = 0.042. Examination of the X-ray emission spectra (XES) has revealed that the main maximum of the FeLα band coincides with the high-energy feature of the P L II,III bands, indicating strong hybridization of P s and Fe d electrons. High intensity of the FeKβ″ satellite has been observed and explained. Two components appear in the 57 Fe Mössbauer spectruma measured at temperatures in the range 80–300 K, Fe1 (77(2)%) and Fe2 (23(2)%). The paramagnetic component reflects Fe in the crystallographic position 4 c . The moderate value of the quadrupole splitting of 0.3758 mm s −1 indicates a slight anisotropy of the electric field created by Fe1 in its nearest environment. The second component (Fe2) is attributed to Fe atoms statistically substituting Ta atoms in the crystal structure. Its broader linewidth and distinct isomer shift support this assignment. The relative intensities and hyperfine parameters remain constant with temperature, indicating two thermally stable Fe environments. Results of ab initio calculations carried out using the fully relativistic spin-polarized linear muffin-tin orbital method show good agreement with the experimental data.

Samples of YPdCd, Y 2 Pd 2 Cd and Y 2 Cu 2 Cd were synthesized from the elements by induction melting. The three cadmium phases were characterized through their Guinier powder patterns. YPdCd crystallizes with the hexagonal ZrNiAl-type structure (space group P 6 ‾ $\overline{6}$ 2 m ; a  = 756.0(4) and c  = 384.7(2) pm). The structure of Y 2 Pd 2 Cd was refined from single-crystal X-ray diffractometer data: Mo 2 B 2 Fe type, tetragonal space group P 4/ mbm , a  = 765.33(3), c  = 370.30(2) pm, w R 2 = 0.0254, 289 F 2 values and 12 variables. Y 2 Pd 2 Cd is a 1:1 intergrowth structure of CsCl and AlB 2 related slabs of compositions ‘YCd’ and ‘YPd 2 ’. The palladium dumb-bells (279 pm Pd–Pd) and the cadmium atoms (301 pm Cd–Pd) form a two-dimensional [Pd 2 Cd] substructure that is separated by yttrium layers in c direction. Consistent with their crystal structures, the 113 Cd solid-state MAS-NMR spectra of Y 2 Pd 2 Cd and isotypic Y 2 Cu 2 Cd show only one signal characterized by strong Knight shift contributions.

Nine new tetrelides RET 3 X 2 ( RE = rare earth element, T = Rh, Ir and X = Si, Ge, Sn) were synthesized from the elements by arc-melting and subsequent annealing between T = 870 and 1,170 K for 10 days. Several other members of the RET 3 X 2 series were reinvestigated by powder X-ray diffraction in order to assign the correct structure type. The structures of LaRh 3 Ge 2 , CeIr 3 Si 2 and EuIr 3 Ge 2 were refined from single-crystal X-ray diffractometer data of trillings. Their ErRh 3 Si 2 -type structure, space group Imma , is an orthorhombically distorted superstructure variant of CeCo 3 B 2 which itself is a coloring variant of the CaCu 5 type (space group P 6/ mmm ). The symmetry reduction induces the trilling formation. Based on the powder and single-crystal diffraction data, most of the RET 3 X 2 phases could be assigned to the ErRh 3 Si 2 type. The RET 3 X 2 phases show Kagome networks built up by the rhodium or iridium atoms and interconnected by the tetrel elements. The rare earth atoms fill cavities with coordination number 18 (orthorhombically distorted hexa-capped hexagonal prisms). The powder data for the stannides RE Rh 3 Sn 2 ( RE = La, Ce, Pr) showed only the CeCo 3 B 2 subcell data. Preliminary single-crystal data indicate a slightly higher rare earth content RE 1+x Rh 3 Sn 2 in the incommensurate composite structures. Temperature dependent magnetic susceptibility data of PrRh 3 Si 2 and EuIr 3 Ge 2 show stable trivalent praseodymium and divalent europium. PrRh 3 Si 2 and EuIr 3 Ge 2 show ferromagnetic ordering at T C = 4.9(5) and 33.3(5) K, respectively. The LaRh 3 Sn 2 sample was characterized through its 119 Sn Mössbauer spectrum, showing an isomer shift value of 1.71(1) mm s −1 .

The dimeric complex [{Cu( μ -I)( A )} 2 ] ( 1 2 ) has been isolated from the reaction of copper(I) iodide with the cyclic (alkyl)(amino)carbene (CAAC) containing a 1,1′-ferrocenylene (fc) backbone fc(CPh 2 –C–NMes) ( A , Mes = mesityl), whereas analogous reactions with conventional CAACs have exclusively afforded monomeric complexes [CuI(CAAC)]. The reaction of tetracarbonylnickel(0) with A furnished the dicarbonyl complex [Ni(CO) 2 ( A )] ( 2 ), whereas tricarbonyl complexes [Ni(CO) 3 (CAAC)] have always been obtained from analogous reactions with conventional CAACs. [{Cu( μ -I)( A )} 2 ] ( 1 2 ) and [Ni(CO) 2 ( A )] ( 2 ) have been structurally characterised by single-crystal X-ray diffraction.

The complexes [Cd(mpca·H)Cl 2 ] · H 2 O ( 1 ) and [Zn(mpca·H)Cl 2 ] ( 2 ) have been synthesized and characterized by single-crystal and IR spectroscopya (mpcaH = 2-morpholine-pyridine-4-carboxylic acid). Both complexes crystallize in the triclinic space group P 1 ‾ $\overline{1}$ , and the cadmium and zinc ions exhibit distorted trigonal bipyramidal and tetrahedral coordination geometries, respectively. In compound 1 , the carboxylate moieties show different μ 1 - η 1 : η 1 and μ 1 - η 1 : η 0 coordination modes, while in 2 , only the μ 1 - η 1 : η 0 mode is observed.

The management of agricultural waste, such as rice husk ash (RHA), is a major environmental issue, particularly because it is often burned in the open air, leading to smog and air pollution, besides greenhouse gas emissions. This article discusses the potential of RHA as a sustainable supplementary cementitious material with added value in agricultural waste reutilization and enhanced properties for construction applications. The rheological and mechanical properties of cement mortar are systematically evaluated by partially replacing ordinary Portland cement (OPC) with RHA (5–25 % by weight). Mortar cubes (50 mm cubes) incorporating RHA demonstrate significant improvements in durability and sustainability metrics. The results reveal that RHA incorporation increases setting time and reduces water absorption and chloride penetration, with up to a 70 % decrease in chloride ingress at just 10 % RHA replacement. Compressive strength exceeds standard cement mortar after 28 days, especially at 5–10 % RHA substitution, indicating better mechanical performance. Although workability is slightly degraded with greater RHA content, this issue is compensated by enhanced durability and environmental benefits. The use of RHA for sustainable production of durable and environment-friendly cement mortar promotes greener construction practices and substantial reductions in greenhouse gas emissions. This study reveals a scalable, sustainable approach to agricultural waste management and construction innovation.