Volume 72, Issue 8

The two isotypic rubidium chalcogenido diferrates Rb 12 [Fe 2 Q 6 ]( Q 2 ) 3 ( Q =S/Se), which both form needles with green-metallic lustre, were synthesized from Rb 2 S, elemental iron, rubidium and sulfur ( Q =S) or from the pure elements ( Q =Se) at maximum temperatures of 500–800°C. Their triclinic crystal structures were determined by means of X-ray single crystal data (space group P 1̅, a =863.960(10)/903.2(3), b =942.790(10)/982.1(3), c =1182.70(2)/1227.4(4) pm, α =77.4740(10)/77.262(6), β =71.5250(10)/71.462(6), γ =63.7560(10)/63.462(5)°, Z =1, R 1=0.0308/0.0658 for Q =S/Se). The structures contain isolated dinuclear anions [Fe III 2 Q 6 ] 6− composed of two edge-sharing [Fe Q 4 ] tetrahedra ( d Fe − Q =223.4–232.3/236.2–244.8 pm), which are also found in the two polymorphs of the pure alkali diferrates Rb 6 [Fe 2 Q 6 ]. The diferrate ions are arranged in layers running in the a / b plane around z =0. Inbetween (around z≈12$z \approx {1 \over 2}$), two crystallographically different disulfide/diselenide ions Q22−$Q_2^{2 - }$ ( d Q − Q =211.1–213.4/237.9–241.1 pm), which are arranged in slightly puckered 3 6 nets, are intercalated. The intra-anionic distances and angles, the Rb coordination numbers and the molar volumes of these two ‘double-salts’ are in accordance with their corresponding reference compounds, Rb 6 [Fe 2 Q 6 ] and Rb 2 Q 2 . In addition, the two polymorphs of Rb 6 [Fe 2 Se 6 ], which are both isotypic with the sulfido analogous (Cs 6 [Ga 2 Se 6 ]-type, monoclinic, space group P 2 1 /c , a =827.84(5), b =1329.51(7), c =1074.10(6) pm, β =127.130(5)°, R 1=0.0443 and Ba 6 [Al 2 Sb 6 ]-type, orthorhombic, space group Cmce , a =1963.70(3), b =718.98(3), c =1348.40(7) pm, R 1=0.0264) were prepared and characterized to complete the series of alkali diferrates(III) with oxido, sulfido and selenido ligands. The electronic band structures of the three Rb salts Rb 6 [Fe 2 Q 6 ], which have been calculated within the GGA+ U approach applying an AFM spin ordering in the dimers and appropriate Hubbard parameters, allow a comparison of the chemical bonding characteristics (e.g. covalency) and the magnetic properties (magnetic moments) within the series of chalcogenido ligands. An analysis of the spin densities enables a comparative consideration of the mechanisms crucial for the magnetic ordering in chalcogenido ferrates. Ultimately, the electronic structure of the new compound Rb 12 [Fe 2 S 6 ](S 2 ) 3 nicely compares with those of the S 2 -free reference compound Rb 6 [Fe 2 S 6 ].

Cu(II) heterogenized on sodium carboxymethyl cellulose (Na-CMC) has been thoroughly characterized by different techniques. Cu(II)-CMC has been applied for the first time in the homocoupling reaction of a variety of terminal alkynes. The catalyst furnished good to excellent yields of the desired products and could be reused six times without loss of catalytic activity. The Cu(II)-CMC catalysis protocol is a new efficient route to synthesize 1,3-diynes under mild conditions.

Reexamination of the syntheses and crystal structures as well as studies of the thermal decomposition of the heavy alkaline earth metal permanganates Ca[MnO 4 ] 2 ·4 H 2 O, Sr[MnO 4 ] 2 ·3 H 2 O and Ba[MnO 4 ] 2 are the focus of this work. As an alternative to the very inelegant Muthmann method, established for the synthesis of Ba[MnO 4 ] 2 a long time ago, we employed a cation-exchange column loaded with Ba 2+ cations and passed through an aqueous potassium-permanganate solution. We later used this alternative also with strontium- and calcium-loaded columns and all the compounds synthesized this way were indistinguishable from the products of the established methods. Ca[MnO 4 ] 2 ·4 H 2 O exhibiting [CaO 8 ] polyhedra crystallizes in the orthorhombic space group Pccn with the lattice parameters a =1397.15(9), b =554.06(4) and c =1338.97(9) pm with Z =4, whereas Sr[MnO 4 ] 2 ·3 H 2 O with [SrO 10 ] polyhedra adopts the cubic space group P 2 1 3 with a =964.19(7) pm and Z =4. So the harder the AE 2+ cation, the higher its demand for hydration in aqueous solution. Consequently, the crystal structure of Ba[MnO 4 ] 2 in the orthorhombic space group Fddd with a =742.36(5), b =1191.23(7) and c =1477.14(9) pm with Z =8 lacks any crystal water, but contains [BaO 12 ] polyhedra. During the thermal decomposition of Ca[MnO 4 ] 2 ·4 H 2 O, the compound expels up to two water molecules of hydration, before the crystal structure collapses after the loss of the third H 2 O molecule at 157°C. The crystal structure of Sr[MnO 4 ] 2 ·3 H 2 O breaks down after the expulsion of the third water molecule as well, but this already occurs at 148°C. For both the calcium and the strontium permanganate samples, orthobixbyite-type α -Mn 2 O 3 and the oxomanganates(III,IV) AE Mn 3 O 6 ( AE =Ca and Sr) remain as final decomposition products at 800°C next to amorphous phases. On the other hand, the already anhydrous Ba[MnO 4 ] 2 thermally decomposes to hollandite-type BaMn 8 O 16 and BaMnO 3 at 800°C.

An efficient one-pot synthesis of α-aminophosphonates of cytosine with aldehydes, diisopropyl H -phosphite, and cytosine with the help of simple magnesium methanolate was discovered. α-Aminophosphonates of cytosine were obtained in good yields under mild conditions. The reaction tolerates both electron-donating and electron-withdrawing substituents of aromatic and aliphatic aldehydes.

In this work, a coordination polymer formed from 4,5-diamino-3-methyl-4 H -1,2,4-triazol-1-ium chloride (DAMT·HCl) and HgCl 2 formulated as [Hg 5 ( μ -DAMT) 2 ( μ -Cl) 6 ( μ 3 -Cl) 2 Cl 2 ] n has been prepared and characterized by elemental analysis, FT-IR, 1 H NMR spectroscopy, and single-crystal X-ray diffraction. X-ray analysis of the complex revealed an organic-inorganic hybrid coordination polymer containing three different mercury atoms with coordination numbers of 4 (HgN( μ -Cl) 2 ( μ 3 -Cl)), 5 (Hg( μ -Cl) 3 ( μ 3 -Cl)Cl), and 6 (HgN 2 ( μ -Cl) 2 ( μ 3 -Cl) 2 ) and seesaw, octahedral, and square pyramidal geometries, respectively. The polymeric chains are extended to a three-dimensional (3D) array by C–H···Cl and N–H···Cl interactions. In addition to these hydrogen bonds, there are Hg···Cl interactions with the mercury atoms with coordination numbers 4 and 5 to complete their pseudo-square planar and -octahedral geometries, respectively.

Two metal-organic coordination polymers constructed from tris( p -carboxylphenyl)phosphine oxide (TPOH 3 ), namely, [Zn(TPOH)(2,2′-bipy)(H 2 O)·H 2 O·DMF] n ( 1 ) and [Zn 2 (TPOH) 2 (1,4-bix) 2 ·5H 2 O] n ( 2 ) (2,2′-bipy=2,2′-bipydine, 1,4-bix=1,4-bis(imidazol-1-ylmethyl)benzene), were synthesized and identified by IR, elemental analysis and single-crystal X-ray diffraction analysis. Both of the 2,2′-bipy and 1,4-bix ligands tailor the complexes 1 and 2 into chain structures. The thermal behavior and solid state photoluminescence properties correlated with the corresponding structural features were investigated.

A new cadmium-organic network [Cd(L)(SO 4 )] ( 1 ) [L=1,3-di(4-imidazolyl)benzene] has been synthesized and characterized by single-crystal X-ray structure determination, IR spectroscopy, elemental analysis, and powder X-ray diffraction. The complex crystallizes in the orthorhombic system with space group Pnma and displays a binodal (3,5)-connected 2D network with (4 2 .6 7 .8)(4 2 .6) topology. The fluorescence properties of complex 1 were investigated.

A detailed synthetic procedure based on the use of urea, dichlorophthalic acid, respective transition metal halides and [NH 4 ] 2 [MoO 4 ] as a catalyst in the melt or by using 1,2,4-trichlorobenzene as a high-boiling inert solvent is described to gain 2,3,9,10,16,17,23,24-metallooctachlorophthalocyanines (MPcCl 8 compounds with M=Mn, Fe, Co, Ni, Cu). In cases that a first purification by subsequent treatment of the crude materials with HCl, NaOH and HCl would not give rise to analytically pure compounds, a second novel purification by using pyridine is described. The degree of purity, exceeding always 98%, is determined by thermogravimetric analysis. Comparative IR, UV/Vis and PXRD studies of the MPcCl 8 compounds are reported.

Single crystals of Sc 2 Pt 9 Si 3 have been obtained from an arc-melted and inductively annealed sample of the starting composition Sc:4Pt:2Si. The Sc 2 Pt 9 Si 3 structure (Tb 2 Pt 9 Ge 3 type, space group C 2/ c ) was refined from single crystal X-ray diffractometer data: a =1303.4(1), b =749.9(1), c =973.5(1), β =116.44(1)°, wR 2=0.0731, 1643 F 2 values and 67 variables. The structure contains three basic coordination polyhedra Sc@Pt 11 , Si1@Pt 8 and Si2@Pt 8 which show a simple condensation pattern avoiding direct Sc–Si and Si–Si bonding.

The gallium-containing Heusler phases ScRh 2 Ga, ScPd 2 Ga, TmRh 2 Ga and LuRh 2 Ga have been synthesized by arc-melting of the elements followed by different annealing sequences to improve phase purity. The samples have been studied by powder X-ray diffraction. The structures of Lu 0.97 Rh 2 Ga 1.03 ( Fm 3̅ m , a =632.94(5) pm, wR 2=0.0590, 46 F 2 values, seven variables) and Sc 0.88 Rh 2 Ga 1.12 ( a =618.91(4) pm, wR 2=0.0284, 44 F 2 values, six variables) have been refined from single crystal X-ray diffractometer data. Both gallides show structural disorder through Lu/Ga and Sc/Ga mixing. Temperature dependent magnetic susceptibility measurements showed Pauli paramagnetism for ScRh 2 Ga, ScPd 2 Ga, and LuRh 2 Ga and Curie-Weiss paramagnetism for TmRh 2 Ga. 45 Sc and 71 Ga solid state MAS NMR spectroscopic investigations of the Sc containing compounds confirmed the site mixing effects typically observed for Heusler phases. The data indicate that the effect of mixed Sc/Ga occupancy is significantly stronger in ScRh 2 Ga than in ScPd 2 Ga.

A series of non-symmetric 1,3-di(alkyloxy)imidazolium salts were synthesized by stepwise alkylation of 1-hydroxyimidazole-3-oxide. The quaternary salts were subsequently functionalized by bromination in 2-position. A 2-azidoimidazolium salt and an imidazoline-2-thione were prepared exemplarily. Crystal structures of two 2-bromo-1-alkyloxy-3-methyloxyimidazolium tribromides and a mercury(II)-thione complex have been determined by X-ray diffraction.

A zinc(II) complex of cis -1,2-diaminocyclohexane (Dach), [Zn(Dach) 2 ][ZnCl 4 ] ( 1 ), was prepared and its structure was determined by X-ray crystallography. Theoretical (density functional theory) studies were performed for the two model compounds, [Zn(Dach) 2 ][ZnCl 4 ] ( 1 ) and {[Zn(Dach) 2 ][ZnCl 4 ]} 3 ( 1 3 ). The structure of complex 1 is composed of [Zn(Dach) 2 ] 2+ cations and [ZnCl 4 ] 2− anions. The Zn1 atom in the cationic complex adopts a severely distorted tetrahedral geometry, while in the anionic part, Zn2 displays only a slight distortion from tetrahedral coordination. The adjacent cations and anions are associated with each other through hydrogen bonding interactions to form a two-dimensional network in the solid state.