Covalent-bond synthesis

The molecular hybridisation essentially embodies the synthesis of strategically designed of altogether newer breeds of bioactive agents either from two or even more compounds having different characteristic features by the aid of covalent-bond synthesis. 

Weidmann. J.L. Kern. J.M. Sauvage. J.P. Muscat. D. Mullins. S. Kohler, W. Rosenauer. C. Rader, H.J. Martin. K. Geerts, Y. Poly[2]catenanes and cyclic oligo[2]catenanes containing alternating topological and covalent bonds Synthesis and characterization. Chem. Eur. J. 1999, 5. 1841-1851. 

Mathematically, the number of covalent bonds formed per generation (reaction step) in an ideal dendron or den-drimer synthesis varies according to a power function of the reaction steps, as illustrated below (Scheme 42.2). It is clear that covalent bond amplification occurs in all dendritic synthesis strategies. In addition to new architectural consequences, this feature clearly differentiates dendritic growth processes from covalent bond synthesis found in traditional polymer chemistry [14],... 

Properties of zinc salts of inorganic and organic salts are Hsted in Table 1 with other commercially important zinc chemicals. In the dithiocarbamates, 2-mercaptobenzothiazole, and formaldehyde sulfoxylate, zinc is covalendy bound to sulfur. In compounds such as the oxide, borate, and sihcate, the covalent bonds with oxygen are very stable. Zinc—carbon bonds occur in diorganozinc compounds, eg, diethjizinc [557-20-0]. Such compounds were much used in organic synthesis prior to the development of the more convenient Grignard route (see Grignard reactions). 

Synthesis and application in molecular biology of double-helical nucleic acids with covalent-bonded chains 98UK274. 

Alpert has shown [47] that poly(succinimide)-silica can be further hydrolyzed to poly (aspartic acid)-silica or condensed with [3-alanine in aqueous solution to form a covalently bonded copolymer of 2-carboxyethyl aspartamide and aspartic acid. The content of carboxyl groups generated by this way has not been quantified directly, but the cation-exchange hemoglobin capacity has been measured for a series of the packings. Thus, the optimal concentration of poly(succinimide) used in the synthesis was found to be 2 5%. 

Fluorescent nanotubes of polyethyleneimine (PEI) and 3,4,9,10-perylenetetra-carboxylicdianhydride (PTCDA) have been prepared through the alternating deposition of polymers and small functional molecules that form covalent bonds (Figure 7.10) [ 120]. The nanotube synthesis starts with the deposition of P EI in the pores of an AAO membrane as the first layer. The PTCDA solutionis then used to bind to the PEI via covalent bonding (Figure 7.10). The electro-optical properties of the small molecule (PTCDA) are retained in the multilayer films of PEI/PTCDA. The prepared nanotubes retain their fluorescent properties for up to 10 months without... 

An interesting way to prepare shock-resistant coatings [381] follows the synthesis of the ABS-terpolymers, e.g. shock-resistant polystyrene, where a soft, elastomeric phase is incorporated in a hard polymer matrix via covalent bonds. Because organic coatings solidify in situ, elastomeric microgels have been synthesized and mixed to a binder which forms the hard matrix phase before the application of this mixture as a coating material. 

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