Syntheses of N10‐substituted 7‐Arylpyrrolo[2,1‐c]‐[1,4]benzodiazepine‐5,11‐diones

Pyrrolo[2,1‐c][1,4]benzodiazepine‐5,11‐dione and its 7‐bromo derivative were alkylated at the N10 atom applying various methods. The resulting products were subjected to Suzuki–Miyaura reactions using a catalyst system consisting of Pd(Cl)₂(PPh₃)₂ and sodium tert‐butanolate in toluene. Results of an X‐ray single crystal analysis are presented.     

Bis­(acetato‐O)­tetrakis­(imidazole‐N3)­nickel(II)

In the title compound, [Ni(C₂H₃O)₂(C₃H₄N₂)₄], the Ni atom is coordinated centrosymmetrically by four N and two O atoms in an octahedral coordination [Ni—N = 1.986 (3) and 2.054 (3) Å; Ni—O = 2.697 (3) Å]. The O atoms of the acetate anions form hydrogen bonds to adjacent imidazole moieties, with the free O atom forming a somewhat shorter bond [N?O = 2.679 (3) and 2.870 (4) Å]. The hydrogen bonds give rise to a two‐dimensional layer structure.     

[1,2‐P2S8]2− – a New Member of the Thiophosphate Family: Synthesis,Crystal Structure and Vibrational Spectrum of [NH4(2.2.2‐cryptand)]2[1,2‐P2S8] and [NH4(18‐crown‐6)]2[1,2‐P2S8]·H2O

Colourless block‐shaped crystals of [(NH₄)₂(2.2.2‐cryptand)₂][P₂S₈] ( 1 ) and [(NH₄)₂(18‐crown‐6)₂][P₂S₈]·H₂O ( 2 ) could be obtained by the reaction of an aqueous solution of ammonium hexathiohypodiphosphate, (NH₄)₄P₂S₆·2 H₂O, with sulfur and 2.2.2‐cryptand or 18‐crown‐6. The crystal structures of both compounds have been determined by single‐crystal X‐Ray diffraction analysis. Compound 1 crystallizes in the monoclinic space group C2/c with a = 2032.7(2), b = 1243.6(2), c = 2244.6(2) pm, β = 98.64(1)°, and Z = 8, whereas compound 2 crystallizes also monoclinic in the space group P2₁/c with a = 2121.3(2), b = 865.5(1), c = 2345.4(2) pm, β = 91.96(1)°, and Z = 4. It could be established that the title compounds contain a new type of six‐membered [1,2‐P₂S₄] ring with P – P bond and three S – S linkages. The tetrahedral environment of each phosphorus is completed by a (formally) single and double bonded sulfur atom attached externally to the [1,2‐P₂S₄] ring. These terminal PS₂ units are mesomerically stabilized according to their P – S distances. FT‐IR and FT‐Raman spectra of the title compounds are recorded and interpreted.     

Water-anion vibrational coupling in some crystallohydrates

In treating the vibrational spectra of crystallohydrates, it is usually assumed that the water molecules vibrate independently (or nearly so) from the rest of the structural units and, consequently, the bands which shift on deuteration are automatically assigned to water modes (internal or external). In a number of hydrates of metal carboxylates, however, we were able to detect indications of water-anion vibrational coupling.     

Translation of pseudo-cross-conjugation into chemistry: cycloadditions of mesomeric betaines to the new ring system spiro[indazole-3,3'-pyrrole

Indazolium-3-amidates (X-ray analysis), readily available on trapping the N-heterocyclic carbene indazol-3-ylidene with isocyanates, underwent [3+2]-cycloadditions with activated triple bonds to spiro[indazole-3,3'-pyrroles]. A combination of NMR techniques such as heteronuclear single quantum coherence (HSQC), heteronuclear multiple bond correlation (HMBC), nuclear Overhauser enhancement spectroscopy (NOESY), and 1H/15N correlations were applied to elucidate the structures of the cycloadducts.     

Functionalized esters as bis-electrophiles in a silicon-induced domino synthesis of annulated carbocycles

The reaction of silyl-substituted carbanion 1b with arene-1,2-dicarboxylates 6, 15 yields indenone derivatives 11, 16 in a domino process involving silyl C→O migration and elimination. However, in a competing pathway, the initial addition of 1b leads to lactone formation (8, 17). Substrates 26, 38 containing an ester group and a bromine substituent react with 1b under substitution of the halogen not allowing silyl migration. But desilylation with TBAF gives reactive carbanions providing benzo-annulated cycloalkanones 29, 40.     

Natural radioactivity and human exposure by raw materials and end product from cement industry used as building materials

During the manufacturing process in the cement industry, raw materials of different levels of natural radioactivity are utilized. In this study we present the radiological impact of cements as a building material and the different raw materials used in their manufacture. A total of 218 samples of raw materials and their end product cements were collected from the cement industry of Macedonia (The Former Yugoslav Republic) during the period 2005–2007. The specific activities, evaluated by gamma spectrometry analysis, showed the highest mean specific activity in fly ash (²²⁶Ra, 107 ± 45 Bq kg^?1; ²³²Th, 109 ± 30 Bq kg^?1; ⁴⁰K, 685 ± 171 Bq kg^?1), which is used as a raw material. However, the final cement product usually has relatively lower activity compared with the activity of the raw material and the mean specific activity of the final cement products were lower (²²⁶Ra, 42 ± 10 Bq kg^?1; ²³²Th, 28 ± 6 Bq kg^?1; ⁴⁰K, 264 ± 50 Bq kg^?1). The radium equivalent activity and the hazard index were calculated for each sample to assess the radiation hazard. The mean annual effective dose originating from the cements was found to be 111 ± 22 μSv y^?1, which is below the recommended EC limit of 300 μSv y^?1.     

New Hexachalcogeno–Hypodiphosphates of the Alkali Metals: Synthesis,Crystal Structure and Vibrational Spectra of the Hexathiodiphosphate(IV) Hydrates K4[P2S6] · 4 H2O,Rb4[P2S6] · 6 H2O,and Cs4[P2S6] · 6 H2O

The new hexathiodiphosphate(IV) hydrates K₄[P₂S₆] · 4 H₂O ( 1 ), Rb₄[P₂S₆] · 6 H₂O ( 2 ), and Cs₄[P₂S₆] · 6 H₂O ( 3 ) were synthesized by soft chemistry reactions from aqueous solutions of Na₄[P₂S₆] · 6 H₂O and the corresponding heavy alkali‐metal hydroxides. Their crystal structures were determined by single crystal X‐ray diffraction. K₄[P₂S₆] · 4 H₂O ( 1 ) crystallizes in the monoclinic space group P 2₁/n with a = 803.7(1), b = 1129.2(1), c = 896.6(1) pm, β = 94.09(1)°, Z = 2. Rb₄[P₂S₆] · 6 H₂O ( 2 ) crystallizes in the monoclinic space group P 2₁/c with a = 909.4(2), b = 1276.6(2), c = 914.9(2) pm, β = 114.34(2)°, Z = 2. Cs₄[P₂S₆] · 6 H₂O ( 3 ) crystallizes in the triclinic space group with a = 742.9(2), b = 929.8(2), c = 936.8(2) pm, α = 95.65(2), β = 112.87(2), γ = 112.77(2)°, Z = 1. The structures are built up by discrete [P₂S₆]^4? anions in staggered conformation, the corresponding alkali‐metal cations and water molecules. O ··· S and O ··· O hydrogen bonds between the [P₂S₆]^4? anions and the water molecules consolidate the structures into a three‐dimensional network. The different water‐content compositions result by the corresponding alkali‐metal coordination polyhedra and by the prefered number of water molecules in their coordination sphere, respectively. The FT‐Raman and FT‐IR/FIR spectra of the title compounds have been recorded and interpreted, especially with respect to the [P₂S₆]^4? group. The thermogravimetric analysis showed that K₄[P₂S₆] · 4 H₂O converted to K₄[P₂S₆] as it was heated at 100 °C.