High-Energetic Salts and Metal Complexes: Comprehensive Overview with a Focus on Use in Homemade Explosives (HME).

Metal-containing compounds form a large and rapidly expanding group of high-energy materials. Many compounds in this class attract the attention of non-professionals, who may attempt the illegal production of explosives. Several of these substances have been commercially available and pose significant danger if used by terrorists or for criminal purposes.

Forensic analytical aspects of homemade explosives containing grocery powders and hydrogen peroxide.

Homemade explosives become a significant challenge for forensic scientists and investigators. In addition to well-known materials such as acetone peroxide trimer, black powder, or lead azides, perpetrators often produce more exotic and less recognized Homemade Explosives (HMEs). Mixtures of hydrogen peroxide with liquid fuels are widely acknowledged as powerful explosives.

The importance of anchoring ligands of binuclear sensitizers on electron transfer processes and photovoltaic action in dye-sensitized solar cells.

The relatively low photon-to-current conversion efficiency of dye-sensitized solar cells is their major drawback limiting widespread application. Light harvesting, followed by a series of electron transfer processes, is the critical step in photocurrent generation. An in-depth understanding and fine optimization of those processes are crucial to enhance cell performance.

Explosives removal and quantification using porous adsorbents based on poly(2-oxazoline)s with various degree of functionalization.

Polymeric porous adsorbents are reported for removal of explosives, namely picric acid, 1,3,5-trinitro-1,3,5-triazinane (RDX), and pentaerythritol tetranitrate (PETN) and their subsequent quantification using direct analysis with ambient plasma mass spectrometry. The adsorbents are obtained by functionalization of short-chain poly(2-oxazoline)s with methyl ester side chains using 4-(aminomethyl)pyridine with a degree of functionalization equal to 0, 5, 10, and 20%. The subsequent step consist of cross-linking using a high internal phase emulsion procedure by further side-chain amidation with diethylenetriamine as crosslinker.

Blockade of persistent colored isomer formation in photochromic 3H-naphthopyrans by excited-state intramolecular proton transfer.

In photochemistry the excited-state intramolecular proton transfer process (ESIPT) is often observed as a highly efficient singlet excited state depletion pathway, which in the presence of a strong intramolecular hydrogen bond may proceed on a subpicosecond time scale. The present work describes the suppression of unwanted transoid-trans isomer formation in photochromic 3H-naphthopyran derivatives by the introduction of a 5-hydroxy substituent. According to time-resolved spectroscopy experiments and excited-state ab initio calculations, transoid-cis → transoid-trans photoisomerization is reduced by a competitive ESIPT channel in nonpolar solvent (cyclohexane).

Mechanistic insights into photochromic 3H-naphthopyran showing strong photocoloration.

3,3-Diphenylbenzo[f]chromene (1) represents an important architectural platform for photochromic systems. Since the practical utility of such chromophores is largely dependent upon the kinetics of coloration and decoloration, elucidating the mechanistic details of these processes is of great value. Toward this end, we studied the photochromic reaction of (3-(2-methoxyphenyl)-3-phenyl-3H-benzo[f]chromene (2) by both time-resolved UV-vis and mid-IR spectroscopies.

Electronic States of Tris(bipyridine) Ruthenium(II) Complexes in Neat Solid Films Investigated by Electroabsorption Spectroscopy.

We present the electric field-induced absorption (electroabsorption, EA) spectra of the solid neat films of tris(bipyridine) Ru(II) complexes, which were recently functionalized in our group as photosensitizers in dye-sensitized solar cells, and we compare them with the results obtained for an archetypal [Ru(bpy)] ion (RBY). We argue that it is difficult to establish a unique set of molecular parameter values by discrete parametrization of the EA spectra under the Liptay formalism for non-degenerate excited states. Therefore, the experimental EA spectra are compared with the spectra computed by the TDDFT (time-dependent density-functional theory) method, which for the first time explains the mechanism of electroabsorption in tris(bipyridine) Ru complexes without any additional assumptions about the spectral lineshape of the EA signal.

Specific Noncovalent Association of Truncated -Functionalized Triangular Homochiral Isotrianglimines through Head-to-Head, Tail-to-Tail, and Honeycomb Supramolecular Motifs.

Chiral isotrianglimines were synthesized by the [3 + 3] cyclocondensation of (,)-1,2-diaminocyclohexane with C5-substituted isophthalaldehyde derivatives. The substituent's steric and electronic demands and the guest molecules' nature have affected the conformation of individual macrocycles and their propensity to form supramolecular architectures. In the crystal, the formation of a honeycomb-like packing arrangement of the simplest isotrianglimine was promoted by the presence of toluene or -xylene molecules.

Gas-phase generation of dinuclear Au(I)-Au(II) complexes by laser desorption ionization mass spectrometry.

Alkali metal chloroaurates(III) were analysed by laser desorption ionization mass spectrometry. Among a number of generated gas-phase ionic clusters, the unusual ions [MAuCl] (were M stands for Na, K, Rb, Cs) were detected. The spectra of metastable ions and quantum mechanics calculations show the presence of unprecedented Au(I)-Au(II) interactions in the clusters.

Effect of β-Ketoiminato Ancillary Ligand Modification on Emissive Properties of New Iridium Complexes.

A series of new bis(benzo[]quinolinato) Ir(III) complexes with modified β-ketoiminato ancillary ligands were synthesized, and their electrochemical, photophysical properties were determined with the support of theoretical calculations. Moreover, all the synthesized heteroleptic Ir(III) complexes were examined as dopants of the host-guest type emissive layers in solution-processed phosphorescent organic light emitting diodes (PhOLEDs) of a simple structure. As expected on the basis of voltammetry measurements as well as DFT calculations, all the compounds appeared to be green emitters.

Signals of diagnostic ions in the product ion spectra of [M - H] ions of methoxylated flavonoids.

Rationale: The main feature of the fragmentation of [M - H] ions of methoxylated flavonoids is the loss of methyl radical (formation of the [M - H - CH ] product ion). Subsequent decomposition of [M - H - CH ] product ions may be useful for identification of a given compound by HPLC/MS. This paper describes how the selected diagnostic fragment ions can be useful during HPLC/MS(-) analysis of methoxylated flavonoids.

Identification of a biliverdin geometric isomer by means of HPLC/ESI-MS and NMR spectroscopy. Differentiation of the isomers by using fragmentation "in-source".

Abstract: A commercially available biliverdin sample was analyzed by means of HPLC/ESI-MS and NMR spectroscopy. It was been found that beside the main IXα 5,10,15 isomer, the sample contains also the geometric isomer IXα 5,10,15 It was also found the isomers behave differentially upon "in-source" fragmentation in negative ion mode (in contrast to the their behavior upon "in-source" fragmentation in positive ion mode and to their behavior upon MS/MS fragmentation in both modes): the relative abundances of deprotonated molecules and fragment ions are significantly different for both isomers, which can be used as an analytical tool to differentiate between the isomers.

Methyl group transfer upon gas phase decomposition of protonated methyl benzoate and similar compounds.

Gas phase decompositions of protonated methyl benzoate and its conjugates have been studied by using electrospray ionization-collision induced dissociation-tandem mass spectrometry. Loss of CO molecule, thus transfer of methyl group, has been observed. In order to better understand this process, the theoretical calculations have been performed.

Scorpionate complexes of aza-18-crown-6 containing fluoronitrophenyl substituents as studied by electrospray ionization mass spectrometry.

Rationale: Coordination of a metal cation by a nitro group is rare and the interaction between them is usually weak. Examples of complexes in which such an interaction takes place are metal complexes of cyclams containing nitrophenyl or nitrobenzyl substituents. It seemed to be interesting to check if in the complexes of the respective crown ether conjugates the interaction can also take place.

Factors Affecting the Performance of Champion Silyl-Anchor Carbazole Dye Revealed in the Femtosecond to Second Studies of Complete ADEKA-1 Sensitized Solar Cells.

Record laboratory efficiencies of dye-sensitized solar cells have been recently reported using an alkoxysilyl-anchor dye, ADEKA-1 (over 14 %). In this work we use time-resolved techniques to study the impact of key preparation factors (dye synthesis route, addition of co-adsorbent, use of cobalt-based electrolytes of different redox potential, creation of insulating Al O layers and molecule capping passivation of the electrode) on the partial charge separation efficiencies in ADEKA-1 solar cells. We have observed that unwanted fast recombination of electrons from titania to the dye, probably associated with the orientation of the dyes on the titania surface, plays a crucial role in the performance of the cells.

Chiral, triformylphenol-derived salen-type [4 + 6] organic cages.

A one-pot synthesis of chiral [4 + 6] tetrahedral cage compounds containing a salen fragment on each face is presented. The formation of the [4 + 6] products remains in contrast to the reaction of 1,3,5-triformylphloroglucinol with chiral diamines where [2 + 3] keto-enamine pseudocyclophanes are formed exclusively. The presence of OH groups determines the structural and spectroscopic properties of these cage compounds while a change in the reaction conditions facilitates the isolation of the microcrystalline products of the specific surface area varying from 5 to 578 m(2) g(-1).

FAPA mass spectrometry of designer drugs.

Application of a flowing atmospheric-pressure afterglow ion source for mass spectrometry (FAPA-MS) for the analysis of designer drugs is described. In this paper, we present application of FAPA MS for identification of exemplary psychotropic drugs: JWH-122, 4BMC, Pentedrone, 3,4-DNNC and ETH-CAT. We have utilized two approaches for introducing samples into the plasma stream; first in the form of a methanolic aerosol from the nebulizer, and the second based on a release of vapors from the electrically heated crucible by thermal desorption.

Complexation of phosphates by 1,3-bis(3-(2-pyridylureido)propyl)-1,1,3,3-tetramethyldisiloxane.

Rationale: Compounds containing a urea or thiourea moiety form complexes with anions thanks to the ability to form quite strong hydrogen bonds. We have synthesized 1,3-bis(3-(2-pyridylureido)propyl)-1,1,3,3-tetramethyldisiloxane (1). Compound 1 contains two urea moieties connected by a long flexible linker; thus, it should be able to adopt a structure suitable for formation of quite stable complexes with anions.

Dynamic Formation of Noncovalent Calixsalen Aggregates.

A procedure for studying "dynamic structural behavior" of large chiral macrocycles is presented. Ion mobility MS, diffusion-ordered NMR spectroscopy (DOSY NMR), and optical rotation (OR) measurements, supported by calculations, are used together as effective complementary methods to study dynamic formation of noncovalent aggregates. It is shown that the monomer-dimer equilibrium is driven by π-π or CH-π interactions and controlled largely by the substitution pattern of the calixsalen skeleton.

The influence of fluorine position on the properties of fluorobenzoxaboroles.

5-Fluoro-2,1-benzoxaborol-1(3H)-ol, a potent antifungal drug also known as Tavaborole or AN2690, has been compared with its three isomers in terms of its activity against several fungi as well as pKa and multinuclear NMR characterization. The molecular and crystal structure of 6-fluoro-2,1-benzoxaborol-1(3H)-ol was determined and compared with that of AN2690.

New gel-like polymers as selective weak-base anion exchangers.

A group of new anion exchangers, based on polyamine podands and of excellent ion-binding capacity, were synthesized. The materials were obtained in reactions between various poly(ethyleneamines) with glycidyl derivatives of cyclotetrasiloxane. The final polymeric, strongly cross-linked materials form gel-like solids.