Search results for "Reactivity"
showing 10 items of 880 documents
Method development for the determination of 1,1-dimethylhydrazine by the high-performance liquid chromatography-mass spectrometry technique.
2018
Unsymmetrical dimethyl hydrazine is highly toxic, carcinogenic compound, widely used for organic synthesis and drug development. Therefore, due to its high reactivity, direct analysis is problematic. Current study proposes to use derivatization reaction to increase selectivity and sensitivity of high-performance liquid chromatography–mass spectrometry method. Different derivatization agents were tested and optimal reaction media was found. Derivatization was performed by using small amounts of reagents to lower the cost of analysis. The full validation of the method was performed and it can be used in a routine control in pharmaceutical analysis. Method sensitivity is 0.15 ppm, and lineari…
Pairing energy effects in cyanide complexes of CpCrIII
1999
International audience; The steric and electronic factors responsible for the reactivity differences between CN and Cl complexes of CpCrIII were examined by DFT/B3LYP computational techniques. The energy difference between quadruplet and doublet [CpCr(CN)2(PH3)], ΔED–Q, was calculated to be 21.2 kcal mol−1 with the LanL2DZ basis set. Although the high-spin configuration is still the ground state for the cyanide complex, the energy gap is 8.7 kcal mol−1 less than that found for the corresponding chloride species. The difference between quadruplet [CpCr(CN)2(PH3)] and doublet [CpCr(CN)2(PH3)2] less free PH3, ΔECr–P, is also smaller than for the Cl system. The components of ΔECr–P for CN and C…
Expressive suppression and enhancement during music-elicited emotions in younger and older adults
2015
International audience; When presented with emotional visual scenes, older adults have been found to be equally capable to regulate emotion expression as younger adults, corroborating the view that emotion regulation skills are maintained or even improved in later adulthood. However, the possibility that gaze direction might help achieve an emotion control goal has not been taken into account, raising the question whether the effortful processing of expressive regulation is really spared from the general age-related decline. Since it does not allow perceptual attention to be redirected away from the emotional source, music provides a useful way to address this question. In the present study…
The Interaction of Person-Affect-Cognition-Execution (I-PACE) model for addictive behaviors: Update, generalization to addictive behaviors beyond int…
2019
We propose an updated version of the Interaction of Person-Affect-Cognition-Execution (I-PACE) model, which we argue to be valid for several types of addictive behaviors, such as gambling, gaming, buying-shopping, and compulsive sexual behavior disorders. Based on recent empirical findings and theoretical considerations, we argue that addictive behaviors develop as a consequence of the interactions between predisposing variables, affective and cognitive responses to specific stimuli, and executive functions, such as inhibitory control and decision-making. In the process of addictive behaviors, the associations between cue-reactivity/craving and diminished inhibitory control contribute to th…
Reactivity of Nickel(II) Porphyrins in oCVD Processes—Polymerisation, Intramolecular Cyclisation and Chlorination
2019
Abstract Oxidative chemical vapour deposition of (5,15‐diphenylporphyrinato)nickel(II) (NiDPP) with iron(III) chloride as oxidant yielded a conjugated poly(metalloporphyrin) as a highly coloured thin film, which is potentially useful for optoelectronic applications. This study clarified the reactive sites of the porphyrin monomer NiDPP by HRMS, UV/Vis/NIR spectroscopy, cyclic voltammetry and EPR spectroscopy in combination with quantum chemical calculations. Unsubstituted meso positions are essential for successful polymerisation, as demonstrated by varying the porphyrin meso substituent pattern from di‐ to tri‐ and tetraphenyl substitution. DFT calculations support the proposed radical oxi…
Synthesis and characterization of vanadyl(IV) complexes of Schiff bases derived from anthranilic acid and salicylaldehyde (or its derivatives) or ace…
1997
Anhydrous, dimeric vanadyl(IV) complexes of Schiff bases derived from [1+1] condensation of salicylaldehyde (or its derivatives) and anthranilic acid, have been synthesized from CH3CN and were characterized by elemental analysis, FTIR, EPR, absorption, TGA, cyclic voltammetry and room temperature magnetic susceptibility measurements. These complexes were found to be oxidized by air in polar solvents like MeOH and DMF to V-V products. The E(1/2) values were found to be around 660 mV indicating that the carboxylate group favours vanadyl(IV) binding when compared to the alkoxo-bound vanadium complexes. Oxidative instability of these complexes are dependent on the substituent on the salicylalde…
C−C Cross-Couplings from a Cyclometalated Au(III) C∧ N Complex: Mechanistic Insights and Synthetic Developments
2021
Abstract In recent years, the reactivity of gold complexes was shown to extend well beyond π‐activation and to hold promises to achieve selective cross‐couplings in several C−C and C−E (E=heteroatom) bond forming reactions. Here, with the aim of exploiting new organometallic species for cross‐coupling reactions, we report on the Au(III)‐mediated C(sp2)−C(sp) occurring upon reaction of the cyclometalated complex [Au(CCH2N)Cl2] (1, CCH2N=2‐benzylpyridine) with AgPhCC. The reaction progress has been monitored by NMR spectroscopy, demonstrating the involvement of a number of key intermediates, whose structures have been unambiguously ascertained through 1D and 2D NMR analyses (1H, 13C, 1H‐1H CO…
Chemistry and reactivity of dinuclear iron oxamate complexes: alkane oxidation with hydrogen peroxide catalysed by an oxo-bridged diiron(III) complex…
2004
[EN] A new dinuclear iron(III) complex with the tetradentate ligand N,N'-o-phenylenebis(oxamate) (opba) has been synthesised, and structurally, magnetically and electrochemically characterised. It possesses an unprecedented triply bridged Fe-2(mu-O)(mu-RCO2...H2O...O2CR)(2) core, whereby two N-amides from the opba ligand complete the square-pyramidal coordination sphere of the O-carboxylate rich iron site (Fe-N = 2.053 Angstrom and Fe-O = 2.015 Angstrom), The antiferromagnetic exchange interaction between the two high-spin Fe-III ions through the oxo bridge (J = -190 cm(-1); H = -JS(1)(.)S(2)) is weaker than that found in related mu-oxo singly bridged diiron(III) complexes. The lessened ant…
The Benefits of Believing in Chance or Fate: External Locus of Control as a Protective Factor for Coping with the Death of a Spouse
2010
The death of a spouse is an extremely stressful life event that consequently causes a large drop in life satisfaction. Reactivity to the loss, however, varies markedly, a phenomenon that is currently not well understood. Because lack of controllability essentially contributes to the stressful nature of this incident, the authors analyzed whether individual differences in belief in external control influence the coping process. To examine this issue, widowed individuals ( N = 414) from a large-scaled panel study were followed for the 4 years before and after the loss by using a latent growth model. Results showed that belief in external control led to a considerably smaller decline in life …
Addiction Research Unit: Affective and cognitive mechanisms of specific Internet‐use disorders
2021
In the eleventh International Classification of Diseases (ICD-11) of the World Health Organization, gambling disorder and gaming disorder are included in the category 'disorders due to addictive behaviours', which can be specified further as occurring either predominantly offline or predominantly online. Other specific problematic behaviours may be considered for the category 'other specified disorders due to addictive behaviours'. The Research Unit FOR 2974, funded by the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG), focuses on the most prominent online addictive behaviours: gaming, pornography use, buying-shopping and social-networks use. The main goal of the Research…