Carboxylates carboxylic

Alteration of positional selectivity will result from built-in solvation of the transition state by an adjacent carboxyl-related function.Aminations will be so affected by carboxyl, carboxylate ion, carboalkoxy and less so by carboxamido groups (cf. Section I,D,2,b, structure 12.) Other substitutions such as alkoxylations can be so affected by carboxamido and amidino groups (cf. Section I,D, 2,b, structure 14). The effect of the cyclic hydrogen-bonded form (63) of 2-carboxamidopyridine on the reactivity of a leaving group is not known. 

Rakhshaee, R., Giahi, M., and Pourahmad, A., Studying effect of cell wall s carboxyl-carboxylate ratio change of Lemna minor to remove heavy metals from aqueous solution, Journal of Hazardous Materials, 163 (1), 165-173, 2009. 

The location of protons in intermolecularly hydrogen-bonded carboxylate-carboxylic acid complexes, for example sodium hydrogen bis(acetate) [1],... 

M Crisma, V Moretto, G Valle, F Formaggio, C Toniolo. First characterization at atomic resolution of the C-activating groups in a peptide synthesis acid chloride, acid azide and carboxylic-carboxylic mixed anhydride. Int J Pept Prot Res 42, 378, 1993. 

Thermodynamically unstable substances (structure below) that serve as enzymatic reaction intermediates and are typically formed by carboxylation carboxyl group transfer) of a sulfhydryl group on a cysteinyl residue of an enzyme. 

Carboxylates Carboxylate salts Carboxylate soaps Carboxy ladon... 

Figure 2. O O hydrogen bond length histograms indicate a difference in the intermolecular potential for various chemical species. Closely matched (symmetric) hydrogen bonds clearly adopt shorter O - O distances. Both X-ray and neutron diffraction data are from the CSD. From top to bottom all O—H O containing species carboxyl-carboxyl, ApKa > 15 carboxyl-carboxylate, ApXa 0 water-water, ApXa 16 hydroxium-water, ApXa 0 carboxyl-water, ApXa 5 water-carboxylate, ApXa 10. The pK values used here are based on typical aqueous values.

Figure 3. O—H bond lengths in O—H---0 hydrogen bonds. The phenomenon of long O—H bonds appdars to be primarily for the cases in which ApKa 0. Neutron diffraction data are from the CSD. From top to bottom all O— carboxyl-carboxylate, ApKa 0 (circles), and carboxyl-carboxyl, Ap/Ca > 15 (crosses) hydroxium-water, Ap a 0 (circles), and water-water, Ap a 16 (crosses) carboxyl-water, ApKa 5 (circles), and water-carboxylate, ApKa 10 (crosses). The p a values used here are based on typical aqueous values.

Interactions between charges and simple dipoles also occur in proteins, and carboxyl-carboxylate interactions (which are acid salts of monobasic carboxylic acids) were examined by Sawyer and James (1982). Fersht et al. (1985) have estimated the free energy change due to a hydrogen bond involving a charged donor or acceptor to be approximately -3 kcal/mol. 

Sulphate Sulphonate Ether sulphate Ether phosphate Ether carboxylate Carboxylate Primary ammonium Secondary ammonium Tertiary ammonium Quaternary ammonium Amine oxide Betaine... 

The use of isonicotinic acid ligands leads to a threefold interpenetrated neutral square grid network in which [Pt(L)2(HL)2] building blocks (L = isonicotinate) (cf. IX), resulting from deprotonation of half of the acid groups, are linked by carboxyl-carboxylate hydrogen bonds (Figure 18) [27c,57]. A network of the same... 

Figure 34 Cross-linking of Ni(p,-SCN)2L2 n coordination polymer via carboxyl-carboxyl hydrogen bonds between isonicotinic acid ligands (L) to give a sheet structure which stacks providing channels that can accommodate polycyclic aromatic hydrocarbon guest molecules, here anthracene [80], Oxygen, nitrogen and key hydrogen atoms are shaded nickel thiocyanate polymer and anthracene guest molecules shown in wireframe style.

Application of Charge-assisted C H O Hydrogen Bonds in Qrganic-Organometallic Crystal Engineering Carboxyl-Carboxylate Hosts with Cationic Metallocene Guests... 

The Sodium Carboxylate/Carboxylic Acid System. This system has been investigated using IR and showing the extremely... 

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