In the title hydrated salt, C19H25N2 +·I−·H2O, the 4-(diethyl­amino)­phenyl unit of the cation is disordered over two positions in a 0.847 (3):0.153 (3) ratio. The cation is twisted, with dihedral angles between the pyridinium and benzene rings of 11.25 (13) and 10.7 (8)° for the major and minor components, respectively. In the crystal, the three components are linked into a centrosymmetric 2:2:2 unit by O—H⋯I and C—H⋯O hydrogen bonds. π–π inter­actions with centroid–centroid distances of 3.5065 (7)–3.790 (9) Å are also present.

In the title benzene-solvated heteroleptic lithium complex, [Li(C25H21P2S2)(C10H8N2)]·C6H6, the LiI ion is four-coordinated in a distorted tetra­hedral geometry by two S atoms and two N atoms of the two chelating ligands, viz. bis­(diphenyl­thio­phosphino­yl)methyl and 2,2′-bipyridine. The 2,2′-bipyridine mol­ecule is slightly twisted with a dihedral angle between the pyridine rings of 7.35 (12)°. Intra­molecular C—H⋯S hydrogen bonds are present. In the crystal, mol­ecules are stacked along the c axis by π–π inter­actions, with centroid–centroid distances of 3.6021 (15) and 3.6401 (16) Å. The crystal structure also features weak C—H⋯π inter­actions.

The asymmetric unit of the title compound, C9H11N3O2, contains two mol­ecules (A and B), which exist in Z conformations with respect to their C=N double bond. The dihedral angles between the benzene ring and the pendant hy­droxy­carbamimidoyl and acetamide groups are 28.58 (7) and 1.30 (5)°, respectively, in mol­ecule A and 25.04 (7) and 27.85 (9)°, respectively, in mol­ecule B. An intra­molecular N—H⋯N hydrogen bond generates an S(6) ring in both mol­ecules. Mol­ecule A also features an intra­molecular C—H⋯O inter­action, which closes an S(6) ring. In the crystal, the mol­ecules are linked by N—H⋯O, N—H⋯N, O—H⋯O, O—H⋯N, C—H⋯O and C—H⋯N hydrogen bonds and C—H⋯π inter­actions, generating a three-dimensional network.

The asymmetric unit of the title compound, 2C2H6N5 +·C4O4 2−, contains two 3,5-diamino-4H-1,2,4-triazolium cations and one squarate dianion. The squaric acid mol­ecule donated one H atom to each of the two 3,5-diamino-1,2,4-triazole mol­ecules at their N atoms. The squaric acid dianion has four C—O bonds which are shorter than a normal single C—O bond (1.426 Å) and are slightly longer than a normal C=O bond (1.23 Å), which indicates the degree of electron delocalization in the dianion. In the crystal, the cations and dianions are linked by N—H⋯N and N—H⋯O hydrogen bonds into a three-dimensional network.

Flavodoxins, which exist widely in microorganisms, have been found in various pathways with multiple physiological functions. The flavodoxin (Fld) containing the cofactor flavin mononucleotide (FMN) from sulfur-reducing bacteria Desulfovibrio gigas (D. gigas) is a short-chain enzyme that comprises 146 residues with a molecular mass of 15 kDa and plays important roles in the electron-transfer chain. To investigate its structure, we purified this Fld directly from anaerobically grown D. gigas cells. The crystal structure of Fld, determined at resolution 1.3 Å, is a dimer with two FMN packing in an orientation head to head at a distance of 17 Å, which generates a long and connected negatively charged region. Two loops, Thr59–Asp63 and Asp95–Tyr100, are located in the negatively charged region and between two FMN, and are structurally dynamic. An analysis of each monomer shows that the structure of Fld is in a semiquinone state; the positions of FMN and the surrounding residues in the active site deviate. The crystal structure of Fld from D. gigas agrees with a dimeric form in the solution state. The dimerization area, dynamic characteristics and structure variations between monomers enable us to identify a possible binding area for its functional partners.

The title compound, [Cu6I6(C2H6N2S)6], was obtained from the reaction of copper(I) iodide with N-methyl­thio­urea (Metu) in equimolar amounts in acetonitile. The complex consists of two six-membered trinuclear Cu3S3I3 cores that combine through triply bridging Metu, forming a hexa­nuclear core which has -3 symmetry. The CuII atom is coordinated by three S atoms of Metu and one iodide ion in a distorted tetra­hedral geometry. The crystal structure is stabilized by N—H⋯I hydrogen bonds and cuprophilic inter­actions [Cu⋯Cu = 3.0264 (9) Å].

The title compound, C16H13Cl2F3N2, exists in an E conformation with respect to the C=N bond [1.2952 (11) Å] and the C—N—N=C torsion angle is 175.65 (8)°. The dihedral angle between the benzene rings is 42.09 (4)°. An intra­molecular C—H⋯F hydrogen bond generates an S(6) ring. In the crystal, the mol­ecules are linked into [101] chains by C—H⋯F hydrogen bonds.

The title dammarane tritepene, 3α,20(S)-dihy­droxy­dammar-24-ene, which crystallized out in a hydrated form, C30H52O2.1.075H2O, was isolated from the Aglaia eximia bark. The three cyclo­hexane rings adopt chair conformations. The cyclo­pentane has an envelope conformation with the quaternary C at position 14 as the flap atom with the maximum deviation of 0.288 (2) Å. The methyl­heptene side chain is disordered over two positions with 0.505 (1):0.495 (1) site occupancies and is axially attached with an (+)-syn-clinal conformation. The hydroxyl group at position 3 of dammarane is in a different conformation to the corresponding hydroxyl in Dammarenediol II. In the crystal, the dammarane and water mol­ecules are linked by ODammarane—H⋯Owater and Owater—H⋯ODammarane hydrogen bonds into a three-dimensional network.

In the title compound, C22H19N5OS·H2O, the naphthalene ring system and the benzene ring [dihedral angle = 85.19 (8)°] make dihedral angles of 87.02 (9) and 14.41 (10)°, respectively, with the pyrazole ring. The mean plane through the 2-methyl­enehydrazinecarbothio­amide group [C—N—N—C(=S)—N; maximum deviation = 0.022 (1) Å] is slightly twisted from the pyrazole ring [dihedral angle = 5.60 (11)°]. In the crystal, mol­ecules are linked by N—H⋯S, N—H⋯O, O—H⋯S, O—H⋯N and C—H⋯S hydrogen bonds into sheets parallel to the ab plane. π–π inter­actions are also observed [centroid-to-centroid distances = 3.7778 (12) and 3.7010 (12) Å].

In the title compound, C23H17Cl2F3N4O3, the triazole ring makes dihedral angles of 50.27 (6) and 82.78 (7)° with the quinoline ring system and the dichloro-substituted benzene ring. The dihedral angle between the quinoline and dichloro-substituted benzene rings is 38.17 (4)°. In the crystal, mol­ecules are linked via C—H⋯N, C—H⋯F and C—H⋯O hydrogen bonds into a three-dimensional network. The crystal is further consolidated by C—H⋯π contacts to the triazole ring and inversion-related π–π inter­actions between the benzene and pyridine rings of quinoline systems [centroid–centroid distance = 3.7037 (7) Å].

In the cation of the title compound, C9H12NO2 +·Cl−, the dihedral angle between the 2-oxoethanaminium N—C—C(=O)– plane [maximum deviation = 0.0148 (12) Å] and the benzene ring is 7.98 (8)°. The meth­oxy group is approximately in-plane with the benzene ring, with a C—O—C—C torsion angle of −2.91 (18)°. In the crystal, the cations and chloride anions are connected by N—H⋯Cl and C—H⋯Cl hydrogen bonds, forming a layer parallel to the bc plane. A C—H⋯π inter­action further links the layers.

In the title compound, C14H15N5O4, the central –C=N—N—C(=O)—C– bridge is nearly planar [maximum deviation = 0.037 (1) Å] and forms dihedral angles of 7.37 (9) and 73.33 (5)°, respectively, with the benzene and imidazole rings. The dihedral angle between the benzene and imidazole rings is 66.08 (9)°. The meth­oxy and nitro groups are nearly coplanar with the benzene and imidazole rings, respectively, with a C—O—C—C torsion angle of 5.9 (2)° and an O—N—C—C angle of −0.2 (2)°. In the crystal, mol­ecules are linked by a pair of N—H⋯O hydrogen bonds with an R 2 2(8) ring motif, forming an inversion dimer. The dimers are further inter­connected by C—H⋯O hydrogen bonds into a sheet parallel to the (111) plane. A C—H⋯π inter­action is also observed between the sheets.

In the title compound, C11H11FN4OS, an intra­molecular N—H⋯O hydrogen bond generates an S(6) ring. In the crystal, mol­ecules form chains through N—H⋯O hydrogen bonds, which are extended by N—H⋯S hydrogen bonds into an infinite three-dimensional network.

In the title mol­ecule, C21H19N3O2, the central pyridine ring makes dihedral angles of 14.46 (9) and 34.67 (8)° with the 4-amino- and 4-eth­oxy-substituted benzene rings, respectively. The eth­oxy group is essentially coplanar with the attached benzene ring [C—O—C—C torsion angle = 178.70 (16)°] as is the meth­oxy group with the pyridine ring [C—O—C—N torsion angle = −3.0 (3)°]. In the crystal, mol­ecules are linked by N—H⋯N hydrogen bonds into chains along [201]. Weak C—H⋯O hydrogen bonds and C—H⋯π inter­actions are also present.

In the title compound, C26H18N2O3, the maximum deviations from planarity for the tetra­hydro-1H-naphtho­[2,3-c]pyrrole and indoline rings systems are 0.091 (1) and 0.012 (2) Å, respectively. These ring systems make a dihedral angle of 89.95 (6)° with each other and they make dihedral angles of 73.42 (8) and 71.28 (9)°, respectively, with the benzene ring. In the crystal, inversion dimers linked by pairs of N—H⋯O hydrogen bonds generate R 2 2(8) loops and C—H⋯O inter­actions connect the dimers into corrugated sheets lying parallel to the bc plane.

The asymmetric unit of the title compound, C22H22O4, consists of two independent mol­ecules (A and B). The cyclo­hexene rings adopt slightly distorted sofa conformations in both mol­ecules. The dihedral angles between the benzene rings are 74.16 (13) and 71.85 (13)° in mol­ecules A and B, respectively. In the crystal, weak C—H⋯O hydrogen bonds link the mol­ecules into a ribbon-like structure along the b axis. Weak C—H⋯π inter­actions are also observed.

The mol­ecule of the title compound, C16H10N2OS, is approximately planar, the dihedral angle between the 1,3-benzothia­zolo[3,2-a]imidazol-3(2H)-one and the benzyl­idene moieties being 4.10 (8)°. A weak intra­molecular C—H⋯S inter­action generates an S(6) ring. No inter­molecular hydrogen bonds are observed in the crystal structure.

The title compound, C21H17NO2, exists in an E conformation with respect to the C=C bond. The pyridine ring forms dihedral angles of 5.57 (7) and 82.30 (9)°, respectively, with the central benzene ring and the terminal phenyl ring. The dihedral angle between the benzene and phenyl rings is 87.69 (8)°. No significant inter­molecular inter­actions are observed.

The asymmetric unit of the title compound, C23H18N2O3S, contains two mol­ecules with comparable geometries. In one mol­ecule, the pyrazole ring forms dihedral angles of 61.65 (11), 47.88 (11) and 63.20 (14)° with the three benzene rings. The corresponding values for the other mol­ecule are 77.19 (11), 43.55 (11) and 63.56 (15)°. In the crystal, both mol­ecules are linked into inversion dimers by pairs of C—H⋯S hydrogen bonds, generating R 2 2(14) loops in each case.

In the title compound, C8H12N2O, the piperidine ring exhibits a chair conformation and its least-squares plane (all atoms) makes a dihedral angle of 32.88 (12)° with the propane­nitrile unit (r.m.s. deviation = 0.001 Å). In the crystal, mol­ecules are linked by C—H⋯O hydrogen bonds, forming chains along [001].

In the title compound, C24H18N2O3S, the benzofuran ring system (r.m.s. deviation = 0.010 Å) forms dihedral angles of 83.13 (17) and 8.92 (14)° with the benzene and thia­zole rings, respectively. The dihedral angle between the benzene and thia­zole rings is 84.51 (19)°. The mol­ecular structure features an intra­molecular C—H⋯O hydrogen bond, which closes an S(6) ring. There are no inter­molecular hydrogen bonds observed in this structure.

In the cation of the title compound, C18H23N2 +·C7H7O4S−·H2O, one ethyl group of the diethyl­amino unit is disordered over two sets of sites in a 0.665 (6):0.335 (6) ratio. The styrylpyridinium unit is nearly planar, with a dihedral angle between the pyridinium and benzene rings of 4.27 (8)°. In the crystal, the anion ring is almost perpendicular to the aromatic rings of the cation; the sulfonate-substituted benzene ring forms dihedral angles of 89.60 (8) and 89.37 (8)°, respectively, with the pyridinium and benzene rings of the cation. In the crystal, the three components are linked into a three-dimensional network by O—H⋯O and C—H⋯O hydrogen bonds. π–π inter­actions with centroid–centroid distances of 3.6999 (9) and 3.7106 (9) Å are also present.

The asymmetric unit of the title compound, C6H11N3O, consists of two independent mol­ecules in which the cyclo­pentane rings adopt envelope conformations with CH2 grouping as the flap and the semicarbazone groups are essentially planar, with maximums deviation of 0.0311 (12) and 0.0285 (12) Å. In the crystal, N—H⋯O, N—H⋯N and C—H⋯O hydrogen bonds link the mol­ecules to form sheets lying parallel to the ab plane.

In the title compound, C20H21N3O2S, the 2,3-dihydro-1H-pyrazole ring is nearly planar (r.m.s. deviation = 0.023 Å) and forms dihedral angles of 16.96 (6) and 38.93 (6)° with the benzene and phenyl rings, respectively. The dihedral angle between the benzene and phenyl rings is 55.54 (6)°. The mol­ecular conformation is consolidated by an intra­molecular C—H⋯O hydrogen bond, which forms an S(6) ring. In the crystal, inversion dimers linked by pairs of N—H⋯Op (p = pyrazole) hydrogen bonds generate R 2 2(10) loops. The dimers are linked by C—H⋯O hydrogen bonds into sheets lying parallel to (100).

In the title compound, C16H16BrNO, the dihedral angle between the benzene rings is 69.8 (2)°. In the crystal, N—H⋯O hydrogen bonds link the mol­ecules into C(4) chains propagating in [100]. Adjacent mol­ecules in the chains are also linked by C—H⋯O inter­actions which, along with the N—H⋯O hydrogen bonds, generate R 2 1(6) loops.