Triazonine-Based Bistable Photoswitches: Synthesis, Characterization and Photochromic Properties

We disclose here dibenzotriazonines as a new class of nine-membered cyclic azobenzenes displaying a nitrogen function in the saturated ring chain. The specific features of these compounds are (i) a...

Crystal structure of 3,6,6-trimethyl-4-oxo-1-(pyridin-2-yl)-4,5,6,7-tetrahydro-1H-indazol-7-aminium chloride and its monohydrate

The title compounds, C15H19N4O+·Cl−and C15H19N4O+·Cl−·H2O, obtained in attempts to synthesize metal complexes using tetrahydroindazole as a ligand, were characterized by NMR, IR and X-ray diffraction techniques. The partially saturated ring in the tetrahydroindazole core adopts a sofa conformation. An intramolecular N—H...N hydrogen bond formed by the protonated amino group and the N atom of the pyridyl substituent is found in the first structure. In the hydrochloride, the organic moieties are linked by two N—H...Cl−hydrogen bonds, forming aC(4) graph-set. In the hydrate crystal, a Cl−anion and a water molecule assemble the moieties into infinite bands showing hydrogen-bond patterns with graph setsC(6),R64(12) andR42(8). Organic moieties form π–π stacked supramolecular structures running along thebaxis in both structures.

3-Amino-1-(3,4-dimethoxyphenyl)-9,10-dihydrophenanthrene-2,4-dicarbonitrile

In the title compound, C24H19N3O2, the partially saturated ring adopts a distorted half-chair conformation with the methylene-C atom closest to the aminobenzene ring lying 0.664 (3) Å out of the plane defined by the five remaining atoms (r.m.s. deviation = 0.1429 Å. The dihedral angle [32.01 (10)°] between the benzene rings on either side of this ring indicates a significant fold in this part of the molecule. The dimethoxy-substituted benzene ring is almost orthogonal to the benzene ring to which it is attached [dihedral angle = 72.03 (9)°]. The molecule has been observed previously as the major component of a 1:19 co-crystal with 2-amino-4-(3,4-dimethoxyphenyl)-5,6-dihydrobenzo[ha]quinoline-3-carbonitrile [Asiriet al.(2011).Acta Cryst. E67, o2873–o2873]. Supramolecular chains with base vector [201] are formed in the crystal structureviaN—H...O hydrogen bonds between the amino H atoms of one molecule interacting with the methoxy O atoms of a neighbouring molecule. The chains are linked into a three-dimensional architecture by C—H...π interactions.

4a-Methyl-2,3,4,4a-tetrahydro-1H-carbazole-6-sulfonamide

In the title molecule, C13H16N2O2S, the nine non-H atoms comprising the indole residue are approximately coplanar (r.m.s. deviation = 0.031 Å). The partially saturated ring adopts a chair conformation. One amine H forms an intermolecular N—H...O hydrogen bond to a sulfonamide O atom, while the other amine H form is connected to the indole N atom of an adjacent moleculeviaan N—H...N hydrogen bond, resulting in a three-dimensional architecture.

3-Amino-1-(thiophen-2-yl)-9,10-dihydrophenanthrene-2,4-dicarbonitrile

In the title compound, C20H13N3S, the partially saturated ring adopts a twisted half-boat conformation with the methylene C atom closest to the aminobenzene ring lying 0.690 (6) Å out of the plane defined by the five remaining atoms. The dihydrophenanthrene residue has a folded conformation [dihedral angle between the outer benzene rings = 26.27 (18)°]. The thiophen-2-yl ring forms a dihedral angle of 63.76 (19)° with the benzene ring to which it is attached. In the crystal, inversion dimers linked by pairs of N—H...N hydrogen bonds generateR22(12) loops. The dimers are linked into layers in thebcplane by weak C—H...π interactions. The thiophen-2-yl ring is disordered over two essentially coplanar but opposite orientations in a 0.918 (4):0.082 (4) ratio.

Capillary Electrophoresis Coupled To Mass Spectrometry for Forensic Analysis

In this review the most important techniques, which are developed to hyphenate capillary electrophoresis to mass spectrometry (CE-MS), suitable for forensic analysis, are summarized. Analytes of interest are divided into four main parts, namely, compounds with amine containing side chains, compounds with N-containing saturated ring structures, other heterocycles and peptides. Sample pre-treatments and direct injection modes used in CE-MS for forensic analysis are briefly discussed from critical point of view. Special emphasis is placed to point out the advantages of mass spectrometric detection compared to UV- and laser- induced fluorescence (LIF) detections.