Gas phase cations

The second ionization energy, /2, of an element is the energy needed to remove an electron from a singly charged gas-phase cation. For copper,... 

Bond Dissociation Energies of Selected Gas-Phase Cations... 

The most comprehensive study of lithium cation basicities for organic bases was conducted by Taft, Gal and coworkers who investigated the effect of molecular structure on the gas-phase cation and proton basicities. Taft s LCA scale was revised and extended, and the lithium cation basicity scale now includes over 200 compounds. In the same work the correlations between gas-phase basicities toward lithium cation (LCB) and proton (GB) were examined. Good correlations are obtained provided that separate lines are drawn for homogeneous families and the differences in slopes are traced back to the different sensitivities to structural effects. Large deviations are explained by either a different attachment center for Li+ and H+ or a chelation effect toward Li+. Figure 5 describes three types of interactions that involve chelation of a lithium cation. 

The Met+—L bond dissociation energies were measured for some Zn-containing gas phase cations using different methods ". Armentrout reviewed guided ion beam studies of transition metal-ligand thermochemistry and reported the following... 

The energy required to dissociate a proton from gas-phase cationic species, BH+, is called the proton affinity of the base B, PA(B), and is measure of both the acidity of BH+ and the basicity of B. 

Fig. 32 The resonance demand r vs. stability relationship for gas-phase cation stabilities. Reproduced with permission from Matsumoto etal. (1995). Copyright 1995...

The identity of the empirical r value for the solvolysis transition state with that for the corresponding gas-phase cation indicates that the structures of the transition states in benzylic solvolyses should be essentially constant and that... 

Figure 16.6 Modulation of cation-n interactions using fluorinated amino acids, (a) Structures of acetylcholine (ACh) and 5-hydroxytryptamine (5-HT). (b) Receptor activation (log[ECS0/ ECso(wt)]) vs. calculated gas phase cation-n binding ability. Data from references [76] and 1771.

Gas-phase cation chemistry of CHnF4 n (0 n=e3) has been investigated using ion-cyclotron resonance spectroscopy 120 the observed stability of the fluoromethyl cations decreases in the sequence ... 

In conclusion, we hope that the bare gas-phase cation computational model will soon join the use of Cl as a replacement for in the historical... 

The role of the coimter anion in MALDI mass spectrometry analysis of PMMA has also been investigated. In the presence of different sodium halides, decreasing ion yields were observed in the order I>Br>Cl. This result has been interpreted in terms of differing abundances of cations made available for gas-phase cationization by laser irradiation of the matrix/analyte/ salt sample, caused by different lattice energies of the salts. ... 

Anicich VG. An index of the literature for bimolecular gas phase cation-molecule reaction kinetics. JPL Publication U.S. (03-19) 2003. p. 1172... 

Soft ionization can be achieved in the gas phase, from the liquid phase, or from the solid phase. Gas-phase cationization techniques have been discussed in previous chapters, especially in Chaps. 5 and 6. Typical examples of liquid-phase ionization techniques are thermospray ionization (TSI) and electrospray ionization (ESI), which are especially important in combining liquid chromatography and mass spectrometry (LC-MS). A wide variety of solid-phase ionization or desorp-tion/ionization techniques have been developed over the years, including field... 

Krossing, I. and Reisinger, A., Chemistry with weakly-coordinating fluorinated alkoxyaluminate anions gas phase cations in condensed phases Coord. Chem. Rev. 250, 2721-2744 (2006). 

Anicich, V.G., 2003. An Index of the Literature for Bimolecular Gas Phase Cation-Molecule Reaction Kinetics. Jet Propulsion I-aboratory—California Institute of Technology, Pasadena, CA, USA, p.ll94, JPI--Ihiblication-03-19. 

Traeger JC, McLoughlin RG (1981) Absolute heats of formation for gas-phase cations. J Am Chem Soc 103 3637-3652... 

Wang, B.H. Dreisewerd, K. Bahr, U. Karas, M. Hillenkamp, F. Gas-Phase Cationization and Protonation of Nai-trals Generated by Matrix-Assisted Laser Desorption. J. Am. Soc. Mass Spectrom. 1993,4,393-398. 

The ECW equation does not apply to gas-phase cation affinities. According to Drago et al. [174], a transfer-energy component is significant in the enthalpy of cation/molecule reactions... 

Table 6.1 Some typical gas-phase cationic Lewis affinity and basicity scaies that can be established from literature data. Only leading references are given. The stoichiometry column refers to the type of adduct (one- or two-ligand adduct) that was studied.

In this chapter, we will follow the definition of affinity and basicity used in the field of gas-phase cation adducts. The affinity and basicity of the ligand are defined as, respectively. 

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