Soft acids hard bases, hydrogen bonds between

The nucleophilicity scale based on the stretching frequency of the hydrogen bond between a nucleophile and an acid (Nu-HX) 97 was tested against experiment using the hard acids HF, HCN, and BF3 and the soft acid BH3.98 The correlation with the hard acids is excellent but fails when a soft acid is used. A new nucleophilicity index, or = 7 (/xa - /t. )2/I M + b)2] 7a, where //A, and //B, are the chemical potentials of the nucleophilic and electrophilic molecules, respectively, and ijA and i B are their respective hardnesses, has been proposed. This gives the relative nucleophilicity that is... [Pg.258]

HYDROGEN BONDS BETWEEN HARD ACIDS AND SOFT BASES... [Pg.1578]

HYDROGEN BONDS BETWEEN SOFT ACIDS AND HARD BASES... [Pg.1579]

Hydrogen bonds between soft acids and hard bases include the CHJn interaction. Thermochemical studies and... [Pg.1579]

The Lewis acid/base complex is formed via an overlap between a doubly occupied orbital of the donor D and vacant orbital of the acceptor A. This acid/base approach was extended by Pearson who divided Lewis acids and bases into two groups, hard and soft, according to their electronegativity and polarizability (principle of hard and soft acids and bases (HSAB concept). Hard acids (e.g., H, Lf, Na, BF3, AICI3, hydrogen-bond donors HX) and hard bases (e.g., F", CL, HO, RO, H2O, ROH, R2O,... [Pg.67]

Solvation of polyaniline is a result of a number of interactions between polymer dopant and solvent (for example. Bom-type solvation, hydrogen bonding, hard-soft acid base interactions, Lewis acid base (donor-acceptor) interactions). [Pg.520]

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