Incremental NH stretching downshift through stepwise nitrogen complexation of pyrrole: a combined jet expansion and matrix isolation study

Oswald, Sönke; Suhm, Martin A.; Coussan, S.

doi:10.1039/c8cp07053a

“…Figure b and Figure c indicate that the peaks of Zn 2p and C 1 s have no obvious deviation before and after adsorption. In Figure d, both the peaks of Au + (88.7 and 84.25 eV) and Au 3+ (87.19 and 90.61 eV) are observed in the spectra of Au 4f, suggesting partial of Au (III) was reduced to Au(I). As displayed in Figure e, the characteristic silver peaks at 374.12 eV and 368.12 eV imply that the adsorbed Ag(I) was completely reduced to Ag 0 .…”

Section: Resultsmentioning

confidence: 95%

“…Generally, the surface charge of adsorbent and the ionic form of metal ions are highly affected by the pH value of the solution . As shown in Figure a, the adsorption capacity of Au (III) decreases rapidly with the pH value, and it is reduced to zero at pH of 11.…”

Section: Resultsmentioning

confidence: 99%

Fast recovery of Au (III) and Ag(I) via amine‐modified zeolitic imidazolate framework‐8

Zhou

¹

,

Hu

²

,

Xu

³

et al. 2020

Applied Organom Chemis

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In this paper, zeolitic imidazolate framework‐8 modified by the ethanediamine (NH2‐ZIF‐8) was employed for adsorbing Au (III) and Ag(I) from aqueous solutions. The adsorption capacities of NH2‐ZIF‐8 towards Au (III) and Ag(I) were found to be significantly affected by the pH values of the solution. The adsorption kinetics studies show that NH2‐ZIF‐8 presents a fast adsorption property towards metals, attaining 93% of adsorption equilibrium uptake for Au (III) within the first 30 min. This phenomenon can be ascribed to the coordination interaction between the amino group and Au (III). The thermodynamic data suggest that the adsorption of NH2‐ZIF‐8 towards Au (III) is endothermic process, while that for Ag(I) is exothermic. The maximum adsorption capacities of NH2‐ZIF‐8 toward Au (III) and Ag(I) can be achieved to 357 mg·g−1 and 222.25 mg·g−1, respectively. The metal ions interference results show that Cu (II) and Ni (II) hardly have no interference on Au (III) adsorption in e‐waste containing 1500 mg·l−1 Cu (II),100 mg·l−1 Ni (II) and 10 mg·l−1 Au (III); while for Ag(I), Cd (II) and Zn (II) have little interference on Ag(I) adsorption in the hybrid solutions containing Ag(I), Ni (II), Cd (II) and Zn (II) with equal concentration (50 mg·l−1), but Ni (II) interference most. The XPS study shows that partial Au (III) was reduced to Au(I), and that Ag(I) was completely reduced to Ag(0) during the adsorption process. The abundant of active sites of NH2‐ZIF‐8 containing C=N, N‐H, and Zn‐OH groups play a key role in the adsorption of Au (III) and Ag(I). In addition, electrostatic interaction can be responsible for the adsorption of Au (III) by NH2‐ZIF‐8. The regeneration experiments results show that the adsorption capacities of NH2‐ZIF‐8 towards Au (III) and Ag(I) can maintain after three cycles. This work provides a reliable method to improve the adsorption kinetics for metal ions.

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“…Cryogenic spectroscopy allows the isolation of weakly bound complexes of molecules with so‐called tag molecules, that is, noble gases or small molecules such as dinitrogen . These complexes can be analyzed directly or utilized for infrared photodissociation (IRPD) experiments . In IRPD, the complexes are cleaved by absorption of photons, which can be recorded by photon intensity changes or by detection of the generated fragments.…”

Section: Resultsmentioning

confidence: 99%

A Universal Quantitative Descriptor of the Dispersion Interaction Potential

Pollice

¹

,

Chen

²

2019

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London dispersion, universally attractive forces originating from fluctuating dipoles,i so mnipresent in molecules.W hile its understanding has recently made tremendous progress,i ts general appreciation is still lagging behind electrostatics.T his can be explained by the simple tools available to study electrostatic interactions,such as electrostatic potential (ESP) maps and partial charges,a nd al ackt hereof for dispersion. We herein report au niversal quantitative descriptor of dispersion interaction potentials,w hicha llows assessing dispersion visually by London dispersion potential (LDP) maps,and quantitatively using the average LDP on the van der Waals surface.W edemonstrate the utility of these new tools by constructing aq uantitative dispersion energy scale of the elements and common substituents,s tudying non-covalent interactions (NCIs), and developing modern linear free energy relationships in catalysis.

show abstract

“…Cryogenic spectroscopy allows the isolation of weakly bound complexes of molecules with so‐called tag molecules, that is, noble gases or small molecules such as dinitrogen . These complexes can be analyzed directly or utilized for infrared photodissociation (IRPD) experiments . In IRPD, the complexes are cleaved by absorption of photons, which can be recorded by photon intensity changes or by detection of the generated fragments.…”

Section: Resultsmentioning

confidence: 99%

“…One main challenge in interpreting IRPD experiments is ascertaining the influence of the tag(s). The question where tags will bind was tackled recently by studying the stepwise cluster formation of pyrrole with dinitrogen, measuring the corresponding IR spectra and comparing them to computations . The preferred binding sites were found to be the π‐system and the N−H group; they can be rationalized based on the ESP and LDP maps of pyrrole (Figure ).…”

Section: Resultsmentioning

confidence: 99%

A Universal Quantitative Descriptor of the Dispersion Interaction Potential

Pollice

¹

,

Chen

²

2019

View full text Add to dashboard Cite

London dispersion, universally attractive forces originating from fluctuating dipoles,i so mnipresent in molecules.W hile its understanding has recently made tremendous progress,i ts general appreciation is still lagging behind electrostatics.T his can be explained by the simple tools available to study electrostatic interactions,such as electrostatic potential (ESP) maps and partial charges,a nd al ackt hereof for dispersion. We herein report au niversal quantitative descriptor of dispersion interaction potentials,w hicha llows assessing dispersion visually by London dispersion potential (LDP) maps,and quantitatively using the average LDP on the van der Waals surface.W edemonstrate the utility of these new tools by constructing aq uantitative dispersion energy scale of the elements and common substituents,s tudying non-covalent interactions (NCIs), and developing modern linear free energy relationships in catalysis.

show abstract

Incremental NH stretching downshift through stepwise nitrogen complexation of pyrrole: a combined jet expansion and matrix isolation study

Abstract: The NH stretch of pyrrole experiences downshifts when expanded with N2 or embedded in pure/mixed N2 matrices, no blueshift.

Cited by 15 publications

References 43 publications

Fast recovery of Au (III) and Ag(I) via amine‐modified zeolitic imidazolate framework‐8

Fast recovery of Au (III) and Ag(I) via amine‐modified zeolitic imidazolate framework‐8

A Universal Quantitative Descriptor of the Dispersion Interaction Potential

A Universal Quantitative Descriptor of the Dispersion Interaction Potential

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