The structure of the title molecule, C16H19N5O7, is mainly determined by the steric effect of a bulky 2,4,6-trinitrophenyl group attached to the N atom of a pyrrolidine ring. Both pyrrolidine rings adopt an envelope conformation, with one of the methylene C atoms as the flap in each case, and the N—C—C—N torsion angle along the bond connecting the two pyrrolidine rings is −174.9 (2)°. The benzene ring of the 2,3,5-trinitrophenyl substituent is deformed and the r.m.s. deviation of its six atoms from the best plane is 0.026 Å. The N atoms of the two nitro groups in the ortho positions deviate from the best plane of the benzene ring by −0.033 (5) and 0.385 (5) Å. These groups, as well as the pyrrolidine ring, are twisted relative to the aromatic ring in the same direction, their best planes forming dihedral angles of 30.2 (2), 64.8 (1) and 46.6 (2)°, respectively, with the ring. An intramolecular C—H⋯O hydrogen bond occurs. In the crystal, there is a short [O⋯C = 3.019 (4) Å] contact between a nitro O atom and a C atom of the benzene ring bearing the nitro group and a C—H⋯O interaction between a methyl H atom and another nitro O atom.
The asymmetric unit of the title compound, C10H8·2C16H14N4, consists of one molecule of N,N′-bis(pyridin-2-yl)benzene-1,4-diamine (PDAB) and one half of the centrosymmetric naphthalene molecule. The PDAB molecule adopts a non-planar conformation with an E configuration at the two partially double exo C N bonds of the 2-pyridylamine units. In the crystal, N—H⋯N hydrogen bonds between the PDAB molecules generate a cyclic R
2(8) motif, leading to the formation of PDAB tapes extending along . The tapes are arranged into (010) layers and the naphthalene molecules are enclosed in cavities formed between the PDAB layers.
The asymmetric unit of the title compound, 2C16H14N4·C8H6N2, consits of one molecule of N,N′-bis(pyridin-2-yl)benzene-1,4-diamine (PDAB) and one half-molecule of quinoxaline (QX) that is located around an inversion centre and disordered over two overlapping positions. The PDAB molecule adopts a non-planar conformation with an E configuration at the two partially double exo C N bonds of the 2-pyridylamine units. In the crystal, these self-complementary units are N—H⋯N hydrogen bonded via a cyclic R
2(8) motif, creating tapes of PDAB molecules extending along . Inversion-related tapes are arranged into pairs through π–π stacking interactions between the benzene rings [centroid–centroid distance = 3.818 (1) Å] and the two symmetry-independent pyridine groups [centroid–centroid distance = 3.760 (1) Å]. The QX molecules are enclosed in a cavity formed between six PDAB tapes.
A third polymorph of the title compound, C16H14N4, has been obtained. The molecule adopts a non-planar conformation with an E configuration at the two partially double exo C N bonds of the 2-pyridylamine units. Like in the triclinic form [Bensemann et al. (2002 ▶). New J. Chem.
26, 448–456], the recognition process between 2-pyridylamine units takes place through formation of a cyclic R
2(8) hydrogen-bond motif, leading to the creation of tapes parallel to .
An earlier developed alkylating path leading to tetraalkylated diaminomaleonitrile derivatives was explored. Attempts to explain the reactivity of the representative dialkylated diaminomaleonitrile 2,3-bis[(3-pyridylmethyl)amino]-2(Z)-butene-1,4-dinitrile during the alkylation reaction were performed using X-ray and density functional theory (DFT) studies. The condensed Fukui functions accompanied by softness indices were found to be useful in explaining its reactivity observed during the reaction. The values of the Fukui functions and condensed softness for electrophilic attack calculated from Mulliken, Löwdin, and natural population analyses closely corresponded to the experimental observations. When 2,3-bis[(3-pyridylmethyl)amino]-2(Z)-butene-1,4-dinitrile disodium salt was treated with dimethyl sulfate at lower temperatures the alkylation reaction prevailed, whereas at higher temperatures the alkylating agent acted as a hydride anion acceptor, which favored the elimination reaction. The tetraalkylated dinitrile 2,3-bis[methyl(3-pyridylmethyl)amino]-2(Z)-butene-1,4-dinitrile was used in the synthesis of tribenzoporphyrazine bearing methyl(3-pyridylmethyl)amino groups, which was subsequently subjected to solvatochromic and metallation studies. The changes observed during metallation seem to result from the coordination of the 3-pyridyl group by a palladium ion. This could influence the configuration of the methyl(3-pyridylmethyl)amino moiety, causing more effective donation of a lone pair of electrons from peripheral nitrogen to the macrocyclic ring.
Electronic supplementary material
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Alkylations; Density functional theory; Diaminomaleonitrile; Tribenzoporphyrazine; X-ray structure determination
p-Phenylenediamine can be obtained as the dihydrate, C6H8N2·2H2O, (I), and in its anhydrous form, C6H8N2, (II). The asymmetric unit of (I) contains one half of the p-phenylenediamine molecule lying about an inversion centre and two halves of water molecules, one lying on a mirror plane and the other lying across a mirror plane. In (II), the asymmetric unit consists of one molecule in a general position and two half molecules located around inversion centres. In both structures, the p-phenylenediamine molecules are arranged in layers stabilized by N—H⋯π interactions. The diamine layers in (I) are isostructural with half of the layers in (II). On dehydration, crystals of (I) transform to (II). Comparison of their crystal structures suggests the most plausible mechanism of the transformation process which requires, in addition to translational motion of the diamine molecules, in-plane rotation of every fourth p-phenylenediamine molecule by ca 60°. A search of the Cambridge Structural Database shows that the formation of hydrates by aromatic amines should be considered exceptional.
In the title compound, [Co(CO3)(C10H9N3)2]Br, a distorted octahedral coordination of the CoIII atom is completed by four N atoms of the two chelating di-2-pyridylamine ligands and two O atoms of the chelating carbonate anion. The di-2-pyridylamine ligands are nonplanar and the dihedral angles between the 2-pyridyl groups are 29.11 (9) and 37.15 (12)°. The coordination cation, which has approximate C
2 symmetry, is connected to the bromide ion via an N—H⋯Br− hydrogen bond. The ionic pair thus formed is further assembled into a dimer via N—H⋯O interactions about an inversion centre. A set of weaker C—H⋯O and C—H⋯Br− interactions connect the dimers into a three-dimensional network.
The structure of the title compound, C12H16N5
+·I−, shows that the methylation reaction with CH3I occurred at the imine N atom at position 5 of the 3,6,7,8a-tetrahydro-2H-diimidazo[1,2-c:1′,2′-e]pyrido[1,2-a][1,3,5]triazine system. In the cation, the sp
3-hybridized C atom belonging to the fused dihydropyrine and dihydro-1,3,5-triazine rings deviates by 0.514 (3) Å from the best plane defined by the remaining cationic non-H atoms. The fused dihydropyridine and dihydro-1,3,5-triazine rings are each in a half-chair conformation with the sp
3-hybridized C atom as a flap. The iodide anion is 3.573 (2) Å from the methylated N atom and exhibits five short C—H⋯I− contacts with distances less than 3.16 Å. The structure has been determined from a non-merohedral twin with twin law [−1 0 0 0 − 1 0 0.115 0 1], minor domain = 0.1559 (12).
The asymmetric unit of the title compound, C12H8N2·C10H10N2·2H2O, contains one half-molecule of phenazine, one half-molecule of naphthalene-1,5-diamine and one water molecule. The phenazine and naphthalene-1,5-diamine molecules are located on inversion centers. The water molecules serve as bridges between the naphthalene-1,5-diamine molecules and also between the naphthalene-1,5-diamine and phenazine molecules. The naphthalene-1,5-diamine and water molecules are connected via N—H⋯O and O—H⋯N hydrogen bonds, forming a T4(2) motif. They are arranged into a two-dimensional polymeric structure parallel to (10) in which the water molecule is a single donor and a double acceptor, whereas the amino group is a double donor and a single acceptor in the hydrogen bonding. These two-dimensional assemblies alternate with the layers of phenazine molecules arranged into a herringbone motif. Each phenazine molecule is hydrogen bonded to two water molecules and thus a three-dimensional framework of hydrogen-bonded molecules is generated.
In the title compound, C10H9NO, the amino and the hydroxy groups act both as a single donor and a single acceptor in hydrogen bonding. In the crystal, molecules are connected via chains of intermolecular ⋯N—H⋯O—H⋯ interactions, forming a two-dimensional polymeric structure resembling the hydrogen-bonded molecular assembly found in the crystal structure of naphthalene-1,5-diol. Within this layer, molecules related by a translation along the a axis are arranged into slipped stacks via π–π stacking interactions [interplanar distance = 3.450 (4) Å]. The amino N atom shows sp
3 hybridization and the two attached H atoms are located on the same side of the aromatic ring.
The title compound, C8H10N8S2·2C2H6SO, was obtained unintentionally during an attempt to prepare a thiolate derivative of trimethyltin. The complete disulfide molecule is generated by twofold rotation symmetry and the C—S—S—C torsion angle around the S—S bond is −85.70 (10)°. The molecules are connected via N—H⋯N hydrogen bonds into strongly corrugated layers parallel to (001), generating an R
2(8) motif. The solvent molecule, which exhibits minor disorder of its S atom [site occupancies = 0.9591 (18) and 0.0409 (18)], is linked to this layer via a pair of N—H⋯O interactions.
In the title inclusion compound, 2C24H40O5·C8H6N2, the unit cell contains two molecules of cholic acid (3α,7α,12α-trihydroxy-5β-cholan-24-oic acid) and one molecule of quinoxaline which implies disorder of the quinoxaline in the space group P21. The amphiphilic molecules of cholic acid assemble, in an antiparallel arrangement, via O—H⋯O hydrogen bonds, into typical corrugated host bilayers which are lipophilic on the outside and lipophobic on the inside. The host framework belongs to the so called α-trans subtype. The quinoxaline molecules are accommodated in lipophilic channels formed between neighboring bilayers with only van der Waals interactions between host and guest. There is a crystallographic twofold screw axis directed along an empty channel in the host framework; however, neighboring guests in any one channel are related by a unit-cell translation along the b axis. Thus, the overall structure is a 1:1 superposition of two such channels related by the crystallographic twofold screw axis.
The asymmetric unit of the title compound, 2C8H6N2·C6H7NO·2H2O, contains two quinoxaline molecules, one molecule of 3-aminophenol and two water molecules which are hydrogen bonded to form a two-dimensional polymeric structure. Each of the symmetry-independent quinoxaline molecules forms separate stacks of different symmetry. In one set of stacks, the molecules are related by a screw axis and are slightly tilted [dihedral angle = 7.12 (1)°]. In the second set of stacks, adjacent molecules are parallel and related by an inversion center [interplanar distances = 3.376 (4) and 3.473 (4) Å].