Capacity, basic complex forming

Abuzaid and Nakhla, and Vidic et al. found that the adsorption of phenol by activated carbons from aqueous solutions in the presence of molecular oxygen in the test environment resulted in a threefold increase in the adsorption capacity of the carbon. This has been attributed to the oxygen induced polymerization reactions on the surface of the carbon. Juang et al. studied liquid-phase adsorption of eight phenohc compounds on a PAN-based activated carbon Fiber in the concentration range of 40 to 500 mg/L and observed that the chlorinated phenols showed better adsorption than methyl substituted phenols. Moreno-CastiUa et al. studied the adsorption of several phenols from aqueous solutions on activated carbons prepared from original and deminerahzed bituminous coal and found that the adsorption capacity depended upon the surface area and the porosity of the carbon, the solubility of the phenolic compound, and the hydrophobicity of the substituent. The adsorption was attributed to the electron donor-acceptor complexes formed between the basic sites on the surface of the carbon and the aromatic ring of the phenol. 

As already noted, it is the basic element of all living and once-living tissue. It has the capacity to combine in a multiplicity of complex chains with other elements to form new chemicals. Some of these you know as carbohydrates, fats, and proteins. But there are many others. There are many different carbohydrates, fats, and proteins that in turn can unite in... 

Clay minerals, oxides, and humic substances are the major natural subsurface adsorbents of contaminants. Under natural conditions, when humic substances are present, humate-mineral complexes are formed with surface properties different from those of their constituents. Natural clays may serve also as a basic material for engineering novel organo-clay products with an increased adsorption capacity, which can be used for various reclamation purposes. 

Guanidines are basic molecules (pA of guanidine = 12.5) with a capacity to form intermolecular contacts mediated by H-bonding interactions. Consequently, they are potentially useful pharmacophores in medicinal chemistry, 1 have proven applications as artificial sweeteners,2,3 and are useful as probes in academic studies of intermolecular associations, including su-pramolecular complexes. Expedited access to these molecules via solid-phase synthesis is therefore a worthy goal. This chapter outlines various... 

Vanadium, niobium, and tantalum are metals which possess the capacity of forming both basic and acidic oxides, and, as they also display several degrees of combining power, the types of compounds they produce are very varied and often complex. The chemistry of these elements is, therefore, of considerable interest. In consequence of the difficulty experienced in separating niobium and tantalum satisfactorily, the compounds of these two elements have not been extensively explored their further investigation certainly offers an attractive field for research. 

The first instance involves the Pt(II) fragment "TpPdMe," used not as a catalyst, but rather as a protecting function for alkynes during catalytic, and indeed stoichiometric, processes, a role that followed from the noted stability of TpPtMe(r 2-RC=CR) complexes, and their capacity to release the alkyne by carbonylation.56 63 Thus, ji-complexes with a series of bis (amide)acetylenes (144-149, Scheme 12, Section III.B.l), formed from the polymeric TpPtMe (126), could be subjected to conditions of catalytic hydrogenation, or basic hydrolysis of the pendant functions, without... 

Poly(ethyleneimine) cross-linked (CPEI) with ethylenedichloride forms stable complexes with copper (II) as well as with cobalt (II). The RC1 type of cross-linked poly(ethyleneimine) having an anion-exchange capacity of 6.8 meq g 1 retains copper from CuS04 and cobalt from 1 M aq. CoCl2 solutions [55], PEI is by itself a weak basic anion-exchange resin and forms stable complexes with anions and cations. The process is probably accompanied with chelate ring formation ... 

For each given acid or Lewis acid (electron acceptor), the capacity of an unsaturated system (electron donor) to form a a-complex is proportional to its basicity (donor force), see series (2). At the same time, the increase in relative reactivity of these compounds with respect to electrophilic attack is observed in the similar sequence [34],... 

The TpRe(CO)(PMc3) fragment is isoelectronic with [CpRe(NO)(PPh3)]+ and yet considerably more electron rich. This stronger tt basic character is reflected in its capacity to bind naphthalene, diasterospecifically, in a r] -coordination mode, to prefer ) -thiophene over ) -thiophene coordination and form stable tt complexes with acetone rather than the more common a-bonded species in, for example, [CpRe(NO)(PPh3 )(acetone)]+. 

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