Gutmann acceptor number

Gutmann acceptor numbers were determined in the "usual" way via the chemical shift variation of triphenylphosphine oxide by Osteryoung et al. [26]. While, again, the donor numbers were concentration- and composition-independent for basic melts, the acidic melts showed a strong composition dependence. Nonetheless, the acidity range was comparably small and was found around 100 (which compares to the acidity of trifluoroacetic acid). The donor number for basic melts was found to be 98, which was, of course. 

TTie solution phase ionization potentials of Br in 16 solvents have been determined by photoeiectron emission spectroscopic technique. The values obtained as the threshold energy E for Br" in various solvents are found to be correlated well with the Mayer-Gutmann acceptor number of solvent. The reorganization energy AC, of solvent after the photoionization of Br" has been obtained from the E value. The AG, values are well reproduced by using a simple model which incorporates the dipole-dipole repulsion and the hydrogen-bond formation in the first solvation layer. The solvation structures of Br" determined by EXAFS are used for the AG, calculation. 

The PEE spectra were obtained with the apparatus in this laboratory. The , values measured with 16 solvents are summarized in Table 1. It is found that the E, value correlates with the Mayer-Gutmann acceptor number. 4, . This correlation indicates that the electronic energy states of solvated anions are mainly... 

Fig. 4.17 Plot of the Gibbs energy of transfer of Cl from water to various non-aqueous solvents against the Gutmann acceptor number AN.

Fig. 4.18 Plot of the MSA parameter A estimated in various solvents for the Cl ion (equation (4.9.5)) against the Gutmann acceptor number AN.

Figure 18 Uptake ( /oS) of Lewis acids by PMMA and ArMCU versus the acidic character of the solutes. The %S is the solute per repeat unit molar ratio in the case of PMMA and the solute per nitrogen atom in the case of ArMCU. The solutes were characterized by AN, the Gutmann acceptor number CCI4, 2.3 l-2,dichloroethane (DCE), 6.4 dichloromethane (DCM) (CH2CI2), 13.5 trichloromethane (TCM), (chloroform) 18.7 hexafluoroisopropanol (HFIP), 66.3 and tri-fluoroacetic acid (TFAA), 111.

They found the frequency of this vibration in DMSO to be shifted by more than 150 cm and to be correlated to the Gutmann acceptor number (AN) for the solvents. Based on our analysis, the frequency shift reflects the acidity and, to a lesser extent, the polarity of the solvent, according to the following equation ... 

The Gutmann acceptor numbers (AN) of some solvents are listed in Table 4.9, together with the Kosower Z values and the Dimroth-Reichardt Ej values characterizing the acceptor strengths. 

The data in Table 4.9 indicate that the Gutmann acceptor numbers (AN) follow a sequence similar to Ej and Z values. There is also a close, almost linear, correlation between the heats of solvation of certain anions, e.g., chloride and Fe(CN)6", and the acceptor numbers. 

A cobalt-59 NMR procedure was elaborated by Laszlo and Stockis [La 80] for the determination of H-bond donation of protic solvent. The Co chemical shifts were found to be in linear correlation with the Gutmann acceptor number of the solvents studied. 

It is generally well understood that values of E1/2 can vary markedly as a function of solvent. Numerous papers have been published in this area and they often include correlations between E1/2 and one or more solvent parameters such as the Gutmann donor number, the Gutmann acceptor number, or the Dimroth-Reichardt parameter [14]. In general, values of E1/2 have been shown to correlate with the Gutmann donor number for electrode reactions of the type where n is a... 

---