Carbazole Plane Research Articles

Organometallic modification approach to the control of push–pull architectures: Synthesis, properties and radical polymerization of chromium N-vinylcarbazole derivatives

In an effort to combine the donor character of the carbazole unit with the electron-withdrawing nature of the chromiumtricarbonyl moiety, which can be further modified by exchange of the CO ligand, a new series of vinyl-type monomers with organometallic push–pull chromophores, ( N-vinylcarbazole)Cr(CO) 2L (L = CO ( 2), PPh 3 ( 4), ( C 3 H 5 ) + BF 4 - ( 5)) and ( N-vinylcarbazole)bisCr(CO) 3 ( 3), have been synthesized and isolated, wherein 2 could be converted into 3 under appropriate conditions. All compounds were characterized spectroscopically, and X-ray crystal structure analyses were performed for 2– 4. The coordination-induced geometrical changes occur predominantly on the N-center and its attached double bond. PPh 3 replaces a CO group leading to the N-vinyl double bond length shortening from 1.274 (12) to 1.245 (9) Å. The distance of Cr from the carbazole plane, which allows estimates of the strength of the metal–ligand π-bonding, is shorter in 3 than in 2 as a result of an electronic communication between the two Cr(CO) 3 groups on each aryl ring of carbazole molecule. Electronic absorption and fluorescence spectral features of these complexes have been studied in terms of the electronic nature of the ligands. The change from 2 to 3 causes a subtle red-shift of the absorption bands due to the electronic transitions within dinuclear-carbazole ring system. The polymerization studies of these complexes under free-radical conditions lead to a better understanding of how the organometallic moiety affects the vinyl polymerization. The intriguing effect of the organometallic moiety on the intrachain excimer formation in the resultant polymers have been shown to be likely.

9-Ethyl-3-methyl-1,6-dinitrocarbazole

The title compound, C15H13N3O4, crystallizes in the triclinic space group P\overline 1. The 6-nitro and methyl groups are essentially planar with the carbazole moiety, while the 1-nitro group is twisted out of the carbazole plane. Two neighboring mol­ecules are associated with each other through one benzene ring, indicating a weak π–π interaction.

Ondansetron Hydrochloride: a Competitive Serotonin 5-HT3 Receptor Blocker

The methyl substituted imidazole ring in the title compound, 2-methyl-1-(9-methyl-4-oxo-2,3,4,9-tetrahydro-1H-carbazol-3-yl) imidazol-3-ium chloride dihydrate, C18H20N3O+.Cl-.2H2O, is approximately perpendicular to the carbazole plane [dihedral angle 87.0(1) degrees]. The water molecules are involved in an elaborate network of hydrogen bonds that reinforce the stability of the dihydrate and the cohesion of the structure.

Structure of the carbazoleAr 2 trimer from high resolution UV spectroscopy

Highly resolved spectra of the 0 0 0 (S 1←S 0) transition of the carbazoleAr 2 complex were measured by mass-selective resonance-enhanced two-photon ionization with a narrow-band pulsed laser (Δν<140 MHz). The parallel c-type rotational band structure displays regular sharp features which are used to find an accurate set of rotational constants of the trimer. From the experimental result a (2¦0) structure of the investigated complex with the two Ar atoms located on one side of the carbazole plane can be excluded. Two possible (1¦1) structures and consequences for the solvation mechanism are discussed.

Crystal and molecular structure of 9-(2,4,6-trinitroanilino)-carbazole, C18H11N5O6

The crystal structure of 9-(2,4,6-trinitroanilino)-carbazole, C18H11N5O6, has been determined by X-ray diffraction. Crystals are monoclinic, space group P21/c, a = 14.686(11), b = 24.601(12), c = 10.047(5) Å, β = 107.76(5)° at 292 K, with Z = 8. The two nitrogen atoms in the central fragment have a staggered conformation with an N—N distance of 1.381(4) Å, which is considerably shorter than N—N distances in related N-picrylhydrazine molecules. The picryl moiety has a geometry similar to that of related N-picrylhydrazine molecules. The title compound contains an [Formula: see text] intramolecular bond to one of the ortho nitro groups on the picryl ring. The carbazole plane of one molecule and the picryl plane of a neighboring molecule overlap to form an infinite linear chain of the form … DhA:DhA … where D represents the carbazole donor, h the linear chain linkage within the molecule, and A represents the picryl acceptor of one molecule. The two interplanar distances between D of one molecule and A of an adjacent molecule are 3.28(13) and 3.34(13) Å, indicating a strong π-molecular interaction.

Structure, luminescence and polymerization of a diacetylene crystal: 1,6-di-(n-carbazolyl)-2,4 hexadiin (DCH)

Carbazole substituted diacetylene (DCH) crystals are monoclinic (P2 1/c, a = 13.6 Å, b = 4.55 Å c = 17.6 Å, β = 94.0°). The carbazole planes are stacked along β with a distance of 3.35 Å. Polymerization occurs by annealing or by γ-irradiation (P2 1/c, a = 12.9 Å, b = 4.90 Å, c = 17.4 Å, β = 108°). The monomer crystals show strong phosphorescence from four traps, the depths of which are 23, 71, 224 and 369 cm −1 respectively. They also show a broad band fluorescence, which might be an excimer emission.