Butallyl­onal 1,4-dioxane hemisolvate

The asymmetric unit of the title compound [systematic name: 5-(1-bromo­prop-2-en-1-yl)-5-sec-butyl­pyrimidine-2,4,6-trione 1,4-dioxane hemisolvate], C11H15BrN2O3·0.5C4H8O2, contains one half-mol­ecule of 1,4-dioxane and one mol­ecule of butallyl­onal, with an almost planar barbiturate ring [largest deviation from the mean plane = 0.049 (5) Å]. The centrosymmetric dioxane mol­ecule adopts a nearly ideal chair conformation. The barbiturate mol­ecules are linked together by an N—H⋯O hydrogen bond, giving a single-stranded chain. Additionally, each dioxane mol­ecule acts as a bridge between two anti­parallel strands of hydrogen-bonded barbiturate mol­ecules via two hydrogen bonds, N—H⋯O(dioxane)O⋯H—N. Thus, a ladder structure is obtained, with the connected barbiturate mol­ecules forming the ‘stiles’ and the bridging dioxane mol­ecules the ‘rungs’

Polymorphic form II of 4,4′-methyl­enebis(benzene­sulfonamide)

In the title compound, C13H14N2O4S2 (alternative names: diphenyl­methane-4,4′-disulfonamide, nirexon, CRN: 535–66-0), the two benzene rings form a dihedral angle of 70.8 (1)°. There are two sets of shorter (H⋯O < 2.1 Å) and longer (H⋯O > 2.4 Å) N—H⋯O hydrogen bonds per sulfonamide NH2 group, which together result in hydrogen-bonded sheets parallel (102). Adjacent sheets are connected to one another by an additional N—H⋯N inter­action so that a three-dimensional network of hydrogen-bonded mol­ecules is formed. The investigated polymorph is identical with the form II previously described by Kuhnert-Brandstätter & Moser [(1981). Mikrochim. Acta, 75, 421–440]

Benzyl­sulfamide

The crystal of the title compound [systematic name: 4-(benzyl­amino)­benzene­sulfonamide], C13H14N2O2S, displays a hydrogen-bonded framework structure. Mol­ecules are doubly N—H⋯O hydrogen bonded to one another via their NH2 groups and sulfonyl O atoms. These inter­actions generate a hydrogen-bonded ladder structure parallel to the a axis, which contains fused R 2 2(8) rings. The NH group serves as the hydrogen-bond donor for a second set of inter­molecular N—H⋯O=S inter­actions

Degradation assessment of archaeological oak (Quercus spp.) buried under oxygen-limited condition

The biological deterioration of archaeological wood under oxygen-limited conditions varies due to the limited activities of microorganisms. It is essential to expand the knowledge of the degradation types and the status of archaeological monuments for selecting the proper consolidates. The physical, chemical, and anatomical properties of approximately 600-650 year old archaeological oak collected from an archaeological site in Iasi-Romania were analysed to assess the quality and to identify the degradation types. The results were compared with similar tests on recently-cut oak. X-ray photoelectron spectroscopy (XPS) revealed the presence of more lignin-related peaks in the archaeological oak, which likely reflected the degradation of the wood carbohydrates as evidenced by the decreased oxygen-to-carbon ratio Cox/Cnon-ox. The differences in cellulose crystallinity were not significant suggesting that any cellulose degradation occurred in the amorphous regions. This was also reflected in the dynamic water vapor sorption analysis where the differences in sorption isotherms and hysteresis of archaeological and recently-cut oaks were marginal. Microscopic analysis of the oak cells illustrated bacterial degradation patterns, while the field emission scanning electron microscopy (FESEM) showed the presence of erosion bacteria in the archaeological oak collected from the site with low oxygen conditions

Synthesis and solid-state characterisation of 4-substituted methylidene oxindoles

Background 4-substituted methylidene oxindoles are pharmacologically important. Detailed analysis and comparison of all the interactions present in crystal structures is necessary to understand how these structures arise. The XPac procedure allows comparison of complete crystal structures of related families of compounds to identify assemblies that are mainly the result of close-packing as well as networks of directed interactions. Results Five 4-substituted methylidene oxindoles have been synthesized by the Knoevenagel condensation of oxindole with para-substituted aromatic aldehydes and were characterized in the solid state by x-ray crystallography. Hence, the structures of (3E)-3-(4-Bromobenzylidene)-1,3-dihydro-2H-indol-2-one, 3a, (3E)-3-(4-Chlorobenzylidene)-1,3-dihydro-2H-indol-2-one, 3b, (3E)-3-(4-Methoxybenzylidene)-1,3-dihydro-2H-indol-2-one, 3c, (3E)-3-(4-Methylbenzylidene)-1,3-dihydro-2H-indol-2-one, 3d and (3E)-3-(4-Nitrobenzylidene)-1,3-dihydro-2H-indol-2-one, 3e, were elucidated using single crystal X-ray crystallography. Conclusions A hydrogen bonded dimer molecular assembly or supramolecular construct was identified in all the crystal structures examined along with a further four 1D supramolecular constructs which were common to at least two of the family of structures studied. The 1D supramolecular constructs indicate that once the obvious strong interaction is satisfied to form hydrogen bonded dimer it is the conventionally weaker interactions, such as steric bulk and edge-to-face interactions which compete to influence the final structure formation

Gliquidone

The title compound {systematic name: N-cyclo­hexyl­carba­moyl-4-[2-(7-meth­oxy-4,4-dimethyl-1,3-dioxo-1,2,3,4-tetra­hydro­isoquinolin-2-yl)eth­yl]benzene­sulfonamide}, C27H33N3O6S, displays an intra­molecular N—H⋯O=S inter­action, as well as inter­molecular N—H⋯O=C hydrogen bonds. The latter inter­actions lead to the formation of hydrogen-bonded chains parallel to the c axis. The conformation of the sulfonyl­urea fragment is in agreement with a recent theoretical study [Kasetti et al. (2010 ▶). J. Phys. Chem. B, 114, 11603–11610]

2,3-Difluoro-N-(2-pyrid­yl)benzamide

The title compound, C12H8F2N2O, crystallizes with two independent mol­ecules in the asymmetric unit. The independent mol­ecules differ slightly in conformation; the dihedral angles between the benzene and pyridine rings are 51.58 (5) and 49.97 (4)°. In the crystal structure, mol­ecules aggregate via N—H⋯Npyridine inter­actions as hydrogen-bonded dimers with the structural motif R 2 2(8), and these dimers are linked via C—H⋯O inter­actions to form a supra­molecular chain

Polythia­zide

The crystal structure of the title compound, C11H13ClF3N3O4S3 (systematic name: 6-chloro-2-methyl-3-{[(2,2,2-trifluoro­eth­yl)sulfan­yl]meth­yl}-3,4-dihydro-2H-1,2,4-benzothia­diazine-7-sul­f­on­amide 1,1-diox­ide; CRN: 346–18–9), exhibits a two-dimensional network of hydrogen-bonded mol­ecules parallel to (01). The NH and NH2 groups act as donor sites and the sulfonyl O atoms as acceptor sites in N—H⋯O hydrogen bonds, and a C—H⋯O interaction also occurs. The thiadiazine ring adopts an envelope conformation with the N atom bonded to sulfur at the tip of the flap, and the methyl substituent is in an axial position