3,6-Dimethyl-N 1,N 4-bis­(pyridin-2-yl)-1,2,4,5-tetra­zine-1,4-dicarboxamide

In the title mol­ecule, C16H16N8O2, four atoms of the tetra­zine ring are coplanar, with the largest deviation from the plane being 0.0236 (12) Å; the other two atoms of the tetra­zine ring deviate on the same side from this plane by 0.320 (4) and 0.335 (4) Å. Therefore, the central tetra­zine ring exhibits a boat conformation. The dihedral angles between the mean plane of the four coplanar atoms of the tetrazine ring and the two pyridine rings are 26.22 (10) and 6.97 (5)°. The two pyridine rings form a dihedral angle of 31.27 (8)°. In the molecule, there are a number of short C—H⋯O interactions. In the crystal, molecules are linked via a C—H⋯O interaction to form zigzag chains propagating along the [010] direction

N 1,N 4,3,6-Tetra­methyl-1,2,4,5-tetra­zine-1,4-dicarboxamide

The asymmetric unit of the title compound, C8H14N6O2, contains two independent mol­ecules. In one mol­ecule, the amide-substituted N atoms of the tetra­zine ring deviate from the plane [maximum deviation = 0.028 (1) Å] through the four other atoms in the ring by 0.350 (2) and 0.344 (2) Å, forming a boat conformation, and the mean planes of the two carboxamide groups form dihedral angles of 10.46 (13) and 20.41 (12)° with the four approximtely planar atoms in the tetra­zine ring. In the other mol­ecule, the amide-substituted N atoms of the tetra­zine ring deviate from the plane [maximum deviation = 0.033 (1) Å] through the four other atoms in the ring by 0.324 (2) and 0.307 (2) Å, forming a boat conformation, and the mean planes of the two carboxamide groups form dihedral angles of 14.66 (11) and 17.08 (10)° with the four approximately planar atoms of the tetra­zine ring. In the crystal, N—H⋯O hydrogen bonds connect mol­ecules to form a two-dimensional network parallel to (1-1-1). Intra­molecular N—H⋯N hydrogen bonds are observed

N,N′-Bis(2,6-diisopropyl­phen­yl)-3,6-di­methyl-1,2,4,5-tetra­zine-1,4-dicarboxamide

In the title mol­ecule, C30H42N6O2, the amide-substituted N atoms of the tetra­zine ring deviate from the approximate plane of the four other atoms in the ring by 0.457 (3) and 0.463 (3) Å, forming a boat conformation. The two benzene rings form a dihedral angle of 47.69 (9)°. Intra­molecular N—H⋯N and weak C—H⋯O hydrogen bonds are observed

1-{[3-(2-Chloro-3,3,3-trifluoro­prop-1-en­yl)-2,2-dimethyl­cyclo­propan-1-yl]carbon­yl}-3-(methyl­sulfon­yl)imidazolidin-2-one

In the title mol­ecule, C13H16ClF3N2O4S, the imidazolidine ring is approximately planar, the largest deviation from this plane being 0.025 (3) Å. The cyclo­propane ring forms a dihedral angle of 64.1 (2)° with the imidazolidine ring. In the crystal, C—H⋯O hydrogen bonds are observed

3,6-Bis(4-chloro­phen­yl)-N 1,N 4-bis­(1-phenyl­eth­yl)-1,2,4,5-tetra­zine-1,4-di­carboxamide

In the title mol­ecule, C32H28Cl2N6O2, the amide-substituted N atoms of the tetra­zine ring deviate from the approximate plane of the four other atoms in the ring by 0.468 (3) and 0.484 (3) Å, forming a boat conformation. The dihedral angle between the two phenyl rings is 67.0 (1)° and that between the two chloro-substituted benzene rings is 73.8 (1)°. Two intra­molecular N—H⋯N hydrogen bonds are observed

3-(2-Chloro-3,3,3-trifluoro­prop-1-en-1-yl)-2,2-dimethyl-N-[3-(trifluoro­meth­yl)phen­yl]cyclo­propane­carboxamide

In the title mol­ecule, C16H14ClF6NO, the cyclo­propane ring forms a dihedral angle of 70.82 (18)° with the benzene ring. The torsion angles about the ethyl­ene and amide bonds are −2.2 (5) (Cl—C—C—C) and 0.8 (5)° (O—C—N—C). A supra­molecular chain propagated by glide symmetry along [001] and mediated by N—H⋯O hydrogen bonds is observed in the crystal packing

2,5-Bis(9H-carbazol-9-yl)thio­phene

The mol­ecules of the title compound, C28H18N2S, are built up from two triply-fused rings and one five-membered ring, with dihedral angles of 66.12 (8) and 70.96 (7)° between the central thio­phene ring and the two triply-fused rings

2,7-Dichloro-4-(chloro­acet­yl)fluorene

There are two mol­ecules in the asymmetric unit of the title compound, C15H9Cl3O. The fluorene rings of the two mol­ecules are both coplanar within 066 (3) Å. In the crystal, C—H⋯O and C—H⋯Cl hydrogen bonds link the mol­ecules into sheets running parallel to (100)

Effect of Original Layer Thicknesses on the Interface Bonding and Mechanical Properties of Ti-Al Laminate Composites

It is of great significance in high-temperature aeroengine applications for large-surface-area TiAl laminate composites to be fabricated into Ti-Al3Ti parts by plastic forming and subsequent vacuum hot pressing. Then the original layer thicknesses have an important influence on the interface bonding and mechanical properties of TiAl laminate composites, but only few reports about it have been published so far. In the present study, vacuum hot pressing was employed to fabricate TiAl laminate composites using Ti and Al foils of different thickness. The resulting interface bond and mechanical properties of TiAl laminate composites were then studied to determine the optimum sheet configuration and thickness. To further assess their formability and develop a forming limit diagram (FLD), 0.1/0.15 TiAl laminate composites were operated on bending and forming tests to provide guidance for subsequent plastic forming of complex geometries. The results indicated that hot pressed laminates composed of alternating 0.1 (Al) and 0.15 (Ti) mm thick sheets exhibited enhanced superior interface bonding and mechanical properties compared with 0.2/0.25 and 0.4/0.4 sheets. The 0.1/0.15 TiAl laminate composites had excellent bending characteristics and reasonable formability. Fabrication of a drawn cup further confirms the potential for hot pressed TiAl laminate composites to be fabricated into complex shapes

3,6-Dimethyl-N 1,N 4-bis­(1-phenyl­eth­yl)-1,4-dihydro-1,2,4,5-tetra­zine-1,4-dicarboxamide

In the title mol­ecule, C22H26N6O2, the central tetra­zine ring exhibits a boat conformation, and the two phenyl rings form a dihedral angle of 88.39 (6)°. In the crystal, weak N—H⋯O and C—H⋯O hydrogen bonds link mol­ecules into layers parallel to the ab plane