Gutmann donor numbers

Gomberg-Bachmann reaction 62, 116, 189, 206, 253ff., 261, 273, 301 Gutmann donor numbers 375... 

From experiments as well as from the Gutmann donor number for acetonitrile (only 50% of that for water), it is well known that addition of water to solutions of lithium ions in acetonitrile leads to the formation of a water coordinated Li+ ion. This can be reproduced for HCN as modeled by quantum chemical calculations (RB3LYP/6-311+G ). 

The ability of molecules to accept a hydrogen bond is measured by the Taft-Kamlet solvatochromic parameter, P, (or P for the monomer of self-associat-ing solutes) (see Table 2.3). This, too, is a measure of their basicity (in the Lewis sense), also measured by the Gutmann donor number DN (discussed later). Thus, pyridine has P = 0.64, compared with 0.40 for acetonitrile, but... 

The enthalpy change during donor-acceptor adduct formation has been related by Drago to the sum of two terms (1) the product of the electrostatic properties of the acid and the base, Ef. and E and (2) the product of their tendency toward covalent bonding, Ca and Cb [10]. For the particular case, where the acceptor is specified to be SbCb (and the inert solvent is 1,2-dichloroethane), the negative of this enthalpy change (in kcal mol", 1 cal = 4.184 J) is the Gutmann donor number, DN [2,11]. These concepts are further discussed in Chapter 3. 

Guanosine nucleotide, redox pathways, 43 129 Guided-ion-beam mass spectrometry, metal-0X0 systems, 44 323 Gutmann donor number, 34 174 Gypsum... 

Many of the studies with amides have included evaluation of ligand-field parameters if appropriate. The differences between different amides are quite small. For [NiL6]2+, Dq varies from 749 cm-1 when L is A-methylcaprolactam to 850 cm1 when L is DMF.44,45 However, the spectro-chemical order in complexes [U02L5]2+ is DMA < NMA as DMF < NMF65 compared with NMA < DMA 4 NMF < DMF for Ni2+ neither series follows the order of donor strengths reflected by the Gutmann donor numbers, which rank DMA marginally above DMF as a donor in terms of the enthalpies of adduct formation with SbCls-66... 

TABLE IV. Gutmann Donor Number (DN),(22c) Dielectric Constant ( EL)T(22a)... 

FIG, 2, Plot of infinite dilution Cs shieldings against Gutmann donor numbers for the respective solvents. (33)... 

Alt the analyses of potentials discussed above were carried out for hard donor solvents. Gutmann donor numbers for soft donors are not available. These numbers were not expected [82] to account for soft-soft interactions. 

It has been tried to overcome this drawback by the use of multi-parameter correlation equations. One approach involves the Gutmann donor number (DN) [81]. By this the absorption maximum (v ) observed for a dye in a certain liquid can be calculated from the absorption maximum of the dye in a reference medium (Vmax.o) according to [82-85]... 

Naumann has studied the trifluoromethylation of the tetracarbonyliron dihalides with Cd(CF3)2DME and Cd(CF3)2(CH3CN)2 in several solvents under polar reaction conditions. Polar reaction conditions include the use of solvents of high Gutmann donor number, which are stated to favor the transfer of the softer CFj anion rather than the harder F- anion to the substrate (52). 

Fig. 4.15 Plot of the Gibbs energy of transfer of Na from water to various non-aqueous solvents against the Gutmann donor number DN.

Fig. 4.16 Plot of the MSA parameter estimated in various solvents for the Na+ ion (equation (4.9.4)) against the Gutmann donor number DN.

Polar molecular solutes have been used to probe the donor-acceptor properties of polar solvents. chemical shifts have been measured for interaction between trifluoroiodomethane and the solvent molecule as electron pair donor [24]. As interaction between the donor molecule and the iodine atom in this molecule increases, electron density at the fluorine atoms increases with a resulting positive chemical shift in the NMR signal. An excellent correlation between these shifts and the Gutmann donor number was reported [24]. 

---