2-(4-Methyl­anilino)acetohydrazide

In the title mol­ecule, C9H13N3O, the non-hydrogen atoms of the hydrazide group are essentially planar [maximum deviation = 0.028 (1) Å for one of the N atoms]. The mean plane of this group forms a dihedral angle of 83.34 (5)° with the plane of the benzene ring. In the crystal structure, mol­ecules are linked by inter­molecular N—H⋯O, N—H⋯N and weak C—H⋯N hydrogen bonds into a two-dimensional network parallel to the ab plane. Additional stabilization is provided by a weak C—H⋯π inter­action

4-Amino-3-[(4-methoxy­phen­yl)amino­meth­yl]-1H-1,2,4-triazole-5(4H)-thione

The mol­ecule of the title compound, C10H13N5OS, is approximately planar, the dihedral angle between the triazole and benzene rings being 4.53 (10)°. The amino group adopts a pyramidal configuration. In the crystal structure, mol­ecules are linked into two-dimensional networks parallel to (001) by inter­molecular N—H⋯S and N—H⋯N hydrogen bonds. In addition, an S⋯S short contact of 3.3435 (7) Å is observed

Diethyl 4-hy­droxy-4-methyl-6-oxo-2-phenyl­cyclo­hexane-1,3-dicarboxyl­ate

In the title mol­ecule, C19H24O6, the cyclo­hexa­none ring adopts a chair conformation. The dihedral angle between the phenyl ring and the best plane through the six atoms of the cyclo­hexa­none ring is 89.68 (7)°. In the crystal structure, mol­ecules are linked via pairs of inter­molecular O—H⋯O hydrogen bonds into centrosymmetric dimers and these dimers are connected by C—H⋯O inter­actions into columns down the a axis

Tribological properties of the directionally oriented warp knit GFRP composites

Recently, directionally oriented warp knit structures have gained prominence as reinforcements in composite materials due to their superior isotropic behaviour compared to other types of textile reinforcements. In the present study, composites prepared from four types of directionally oriented warp knit glass preforms with three different thermoset resins have been considered for the tribological characterisation. The tribological tests have been conducted on a reciprocating sliding test rig with ball-on-plate configuration. The tests were conducted in dry (unlubricated) and wet (aqueous) conditions at a fixed applied load (100 N) by varying the sliding distance. E-glass warp knitted preforms were used for the study including biaxial, biaxial non-woven, triaxial and quadraxial fabrics. The matrices were three different thermoset resins namely polyester, vinyl ester and epoxy resin. 13 14 15 16 17 18 19 The main aim of the study was to identify a composite having the best tribological performance, with regard to types of preform and matrix resin. Moreover, the results obtained from the tests have been used to develop a wastage map for these composites, as a function of sliding distance and type of preform in order to have a clear understanding of the tribological process.Fundação para a Ciência e a Tecnologia (FCT

6-(4-Bromo­phen­yl)-2-eth­oxy-4-(2,4,5-trimethoxy­phen­yl)nicotinonitrile1

There are two mol­ecules in the asymmetric unit of the title compound, C23H21BrN2O4, which differ in the conformation of their ethoxy residues, i.e. almost co-planar with the pyridine ring in one mol­ecule [C—O—C—C = −174.0 (2)°] but almost perpendicular in the other [C—O—C—C = 92.8 (3)°]. The dihedral angles between the central pyridine ring and the 4-bromo­phenyl and 2,4,5-trimethoxy­phenyl rings are 11.05 (12) and 63.78 (12)°, respectively, in one mol­ecule; the corres­ponding angles in the other mol­ecule are 30.38 (13) and 65.38 (13)°, respectively. In the crystal structure, pairs of mol­ecules are arranged in a face-to-face sandwich structure which further stacks along the b axis. The crystal packing features C—H⋯π inter­actions and Br⋯O [3.5417 (17) Å], Br⋯C [3.748 (3) Å], C⋯N [3.376 (4) Å] and C⋯O [3.351 (3)–3.409 (3) Å] contacts. Finally, π⋯π inter­actions [centroid⋯centroid distances = 3.6346 (19) and 3.6882 (19) Å] are observed

Ethyl 2-[(2,6-dimethyl­phen­yl)hydrazono]-3-oxobutanoate

The title compound, C14H18N2O3, crystallizes with two independent mol­ecules in the asymmetric unit, having closely comparable geometries. Both mol­ecules are essentially planar [maximum deviations from the mean plane of 0.069 (1) and 0.068 (1) Å for the two mol­ecules] and contain an intra­molecular N—H⋯O hydrogen bond which generates a ring with graph-set motif S(6). In the crystal, the mol­ecules are linked into chains along the c axis by inter­molecular C—H⋯O hydrogen bonds, and inter­molecular C—H⋯π inter­actions are also present

4-Amino-3-(p-tolyl­oxymeth­yl)-1H-1,2,4-triazole-5(4H)-thione

In the title triazole compound, C10H12N4OS, the triazole ring is essentially planar [maximum deviation = 0.009 (1) Å] and forms a dihedral angle of 5.78 (4)° with the benzene ring. In the crystal structure, mol­ecules are linked into dimers by centrosymmetric N—H⋯S inter­actions. These dimers are linked into two-mol­ecule-wide tapes by N—H⋯N and S⋯S [3.2634 (3) Å] inter­actions. In addition, they are further inter­connected by weak N—H⋯S inter­actions into sheets parallel to the ab plane. The crystal structure is further stabilized by weak inter­molecular C—H⋯π inter­actions

(E)-1-(4-Bromo­phen­yl)ethan-1-one semicarbazone

In the title compound, C9H10BrN3O, the hydrazone portion and aliphatic chain are essentially coplanar [maximum deviation 0.057 (15) Å] and the mean plane makes a dihedral angle of 70.9 (6)° with the benzene ring. The main feature of the crystal structure is the inter­molecular N—H⋯O hydrogen bond, which links mol­ecules into zigzag chains along the a axis. These chains are further stacked along the b axis. The crystal structure features non-classical inter­molecular C—H⋯O inter­actions. The crystal studied was a nonmerohedral twin, with a twin ratio of 0.505 (1):0.495 (1)

(E)-1-(4-Fluoro­phen­yl)ethan-1-one semicarbazone

In the title compound, C9H10FN3O, the semicarbazone group is nearly planar, with the maximum deviation of 0.044 (1) Å for one of the N atoms. The mean plane of semicarbazone group forms a dihedral angle of 30.94 (4)° with the benzene ring. The mol­ecules are linked into a supra­molecular chain by N—H⋯O hydrogen bonds formed along the c axis. The crystal structure is further stabilized by weak inter­molucular C—H⋯π inter­actions; the closest C⋯Cg contact is 3.6505 (11) Å