Synthesis and reactivity of metal-containing monomers

Acid and neutral Co^II, Cu^II, Ni^II, Zn^II, Fe^II, and Fe^III maleates, fumarates, and itaconates were obtained and characterized. The methods for their synthesis were optimized, and the valence state and coordination of metals were studied. Co^II and Fe^II hydrogen maleates, Co^II maleate, and Co^II fumarate were examined by X-ray diffraction analysis. The ligands based on unsaturated dicarboxylic acids can be mono-, bi-, and tetradentate, which results in the formation of acid salts, chain and three-dimensional coordination polymers, whose double bond is not involved in the coordination. The strong antiferromagnetic exchange (μ_elf=1.41 and 0.34 μ_B at 290 and 80 K, respectively) was detected in Cu^II itaconate. Based on the data of Mössbauer spectroscopy, the partial reduction of Fe^III to Fe^II during the synthesis of Fe^III maleate was shown to occur: δFe=0.43 and 1.27 mm s^?1, ΔE _Q=0.57 and 3.13 mm s^?1 and Γ=0.37 and 0.28 mm s^?1 atT=298 K for Fe^III and Fe^II, respectively.     

Similarities and differences in the electron ionization-induced fragmentation of structurally related N-alkoxymethyl lactams and sultams

Unimolecular fragmentation patterns of the molecular ions of selected lactams and sultams bearing alkoxymethyl group at the nitrogen atom were studied. The main common fragmentation reaction observed for all compounds studied in this work is the elimination of an aldehyde molecule. This reaction is considered to proceed via two different mechanisms. For lactams, hydrogen rearrangement within an alkoxymethyl group is observed, which leads to the appropriate N-methyl derivatives. For sultams, transfer of the methyl group to the nitrogen and oxygen atoms, proceeding through an ion-neutral complex, dominates. Another important fragmentation channel characteristic exclusively for lactams is the loss of an alkyl radical. This process takes place within the N-alkoxymethyl moiety, yielding the appropriate protonated ion of N-formyllactams. This process is accompanied by relatively high kinetic energy release.     

Thermochemical Properties of Neutral Complexes in Layer Silicates I. [Ni(4-Etpy)4(NCS)2] complex in montmorillonite and pillared montmorillonites

The stoichiometry of thermal decomposition and enthalpy and structural changes were studied for the compounds formed by penetration of [Ni(4-Etpy)4(NCS)2] (I) into Ca-montmorillonite (II) or Cr-, Zr- and Al-pillared analogues (III, IV and V, respectively). The mass fractions of complex I in II, III, IV or V are different. It was found for all studied compounds that the release of L (L=4-Etpy) is a three-step process (-2L, -1L, -1L), and differences occurred in enthalpy changes (δH in kJ per mole of I) corresponding to the individual processes. These differences and the changes in diffraction and spectral properties of the species formed after intercalation are assumed to have their roots in different intramolecular guest-host interactions in the studied compounds. This revised version was published online in July 2006 with corrections to the Cover Date.     

Lipids of Capsicum annuum Fruit Pulp

Lipids from fruit pulp of the sweet red pepper (Capsicum annuum, Solanaceae) were characterized. The principal components of the lipids from pepper fruit pulp were neutral lipids with predominance of triacylglycerines (55.8%). The polar lipids contained sulfoquinovosyldiacylglycerines and phosphotidylglycerines. The fatty-acid compositions of the neutral lipids, glycolipids, and phospholipids were determined.     

Multi-Residue Analysis by Liquid Chromatography-Mass Spectrometry Coupling. Application to Drinking and River Waters

Abstract

The coupling between liquid chromatography and mass spectrometry with an APCI or ESI interface (in positive or negative mode) is used here for multi-residue analyses in natural waters, covering basic and neutral pesticides as well as acid pesticides. The methods developed are applied to drinking and, river waters after the samples are concentrated by liquid-liquid extraction or solid phase extraction on C18 cartridges. Comparisons are made between UV detection and mass spectrometry and between two chromatographic methods for acid substances. The quantitation limits range from 0.01 to 0.1 μg/l according to the substance.     

Toxicological screening of human plasma by on‐line SPE‐HPLC‐DAD: identification and quantification of acidic and neutral drugs

A multi‐analyte screening method for the quantification of 50 acidic/neutral drugs in human plasma based on on‐line solid‐phase extraction (SPE)–HPLC with photodiode array detection (DAD) was developed, validated and applied for clinical investigation. Acetone and methanol for protein precipitation, three different SPE materials (two electro‐neutral, one strong anion‐exchange, one weak cation‐exchange) for on‐line extraction, five HPLC‐columns [one C₁₈ (GeminiNX), two phenyl‐hexyl (Gemini C₆‐Phenyl, Kinetex Phenyl‐Hexyl) and two pentafluorophenyl (LunaPFP(2), KinetexPFP)] for analytical separation were tested. For sample pre‐treatment, acetone in the ratio 1:2 (plasma:acetone) showed a better baseline and fewer matrix peaks in the chromatogram than methanol. Only the strong anion‐exchanger SPE cartridge (StrataX‐A, pH 6) allowed the extraction of salicylic acid. Analytical separation was carried out on a Gemini C₆‐Phenyl column (150 × 4.6 mm, 3 µm) using gradient elution with acetonitrile–water 90:10 (v/v) and phosphate buffer (pH 2.3). Linear calibration curves with correlation coefficients r ≥ 0.9950/0.9910 were obtained for 46/four analytes. Additionally, this method allows the quantification of 23 analytes for therapeutic drug monitoring. Limits of quantitation ranged from 0.1 (amobarbital) to 23 mg/L (salicylic acid). Inter‐/intra‐day precisions of quality control samples (low/high) were better than 13% and accuracy (bias) ranged from ?14 to 10%. A computer‐assisted database was created for automated detection of 223 analytes of toxicological interests. Four cases of multi‐drug intoxications are presented. Copyright © 2015 John Wiley & Sons, Ltd.     

Protein Staining Agents from Cationic and Neutral Luminescent Iridium(III) Complexes

Seven luminescent iridium(III) complexes were prepared to investigate the relationships between chemical structures and properties of protein staining. For the first time, the effect of the main ligand, the π conjugation effect of the ancillary ligand, and the charge effect of organometallic complexes on protein staining has been revealed. Most importantly, this study gives the first experimental evidence of the potential applications of charge‐neutral organometallic complexes in protein staining, which could open an avenue of exploiting novel protein staining agents in the future.     

Rhodium(III)-Catalyzed C−H/N−H Functionalization with Hydrogen Evolution

A rhodium(III)-catalyzed C−H/N−H bond functionalization of benzimidates with α-chloroaldehydes to afford isoquinolin-3-ol derivatives is reported. No external oxidants are needed in this process, and interestingly, evolution of hydrogen gas is observed.