Group softness

The course of this reaction could be explained by nucleophilic attack of the isothiocyanato group on C-5 (hard site) of enamine 61, with the formation of 199 by way of intermediate 198. However, this occurs only in N,N-dimethylformamide or acetonitrile solution. The formation of the additional products 2-glycosyliminothiazolo[4,5-d]pyrimidine-4,6-dione (201) by way of intermediate 200, by attack of the isothiocyanato group on the 6-amino group (soft site), was observed when the reaction was performed in oxolane solution. On the other hand, treatment of isothiocyanates 2, 30,... 

To distinguish among major fields nt applications, ferrites can he separated into live groups Soft, square-loop. hard, microwave, and single-crystal lerrites. 

DN Depletion/no effect Cs, Ag, Mo Heterogeneous group soft ions... 

Plus two background coefficients, coordinates, PO4 group soft-restrained with weight 4 13.3 16.8 22.6 67.6... 

These jr-bonding effects are part of the theory of the HSAB Principle. We can also imagine that London dispersion energies between atoms or groups in an A B complex could stabilize it. Since these dispersion energies, or van der Waals energies, depend on the product of the polarizabilities of the two groups, soft-soft combinations would be stabilized in this way. The hydride ion is very polarizable, and its softness depends on this factor, presumably. 

Apart from the local and global softness (hardness), the concept of group softness (hardness) has been introduced [19], especially for studying the electronic effect of substituents in aromatic compounds [25]. It also applies to solids and can be directly calculated according to the additivity rule for local softness, Eq. (23). Yet another related quantity can be defined, which is useful for understanding observed trends and which has considerable predictive value. 

Lewis CL, Anthamatten M (2013) Synthesis, swelling behavior, and viscoelastic properties of functional poly(hydroxyethyl methacrylate) with ureidopyrimidinone side-groups. Soft Matter 9(15) 4058-4066... 

Organomercury halides are accessible by a number of routes (Chapter 2). Generally the Grignard method is quite convenient. The polarizable RHg— group ( soft acid) prefers to bind the heavier halogens (I > Br > Cl), so that if X = Br or I, the product is mainly RHgBr or RHgl. 

Some of the chemical reactions occurred by participation of group of atoms rather than one atom. Krishnamurty et al. [132] explained those kinds of reaction using the concept of group softness. Group softness is the sum of softness values of the group of relevant atoms and it can be written as... 

Krishnamurly S, Pal S (2000) Intermolecular reactivity trends using the concept of group softness. J Phys Chem A 104(32) 7639-7645... 

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