Direct condensation coupling

In direct LRET the direct electronic coupling between D and A is negligible and this mechanism is not practically realized in condensed media being non-competitive with the consecutive and superexchange processes. In theoretical consideration of the consecutive LRET a relevant theory ofET in two-term systems can be applied. 

Oligomers of this type have not often been made from nonheterocyclic monomers by direct condensation and ring closure, but the following is an example. Catalytic reduction of o-cyanobenzophenone over Raney nickel yields 1-phenylisoindole accompanied by the oxidative coupling product (175) this structure has been confirmed by X-ray analysis.246... 

This relation gives the mass flux directly without coupling to the condensed phase solution, and can be expressed functionally as... 

Isolated highly dispersed titanium oxide species on silica as photocatal5dic active sites for non-oxidative direct methane coupling, were successfiilly prepared by sol-gel method, in which hydrolysis of TEOS to form Si(OH)4 would be completed, followed by condensation to form Si-O-Ti bonds. It was found that both hydrolysis and condensation time much affected the formation of the isolated highly dispersed species. The sample prepared by the present sol-gel method showed higher activity than those prepared by conventional impregnation method. 

Coupling formation of the biopolymeric linkage that joins two monomers or the new monomer to the chain by either activation-condensation or direct dehydration coupling. 

Phosphodiesteric/peptidic/glycosidic bond formation (coupling reaction) is a nucleophilic substitution reaction of a hydroxy/amino/hydroxy group at a phosphoesteric/carboxyl/ acetal group, resulting in dehydration. The coupling reaction can be conducted in two procedures activation-substitution (via stable activated intermediate) and direct condensation... 

Direct condensation. The direct condensation of biomonomers between the two coupling centers can be initiated by the use of coupling reagents such as carbodiimides ... 

Several fiber treatments are reported in literature [9], namely (a) physical treatments, such as solvent extraction (b) physico-chemical treatments, like the use of corona and plasma discharges or laser, y-ray and UV bombardment and (c) chemical modifications, both by the direct condensation of the coupling agents onto the cellulose surface and by various grafting strategies calling upon polycondensations and free-radical or ionic polymerizations. 

In view of these previous developments, we directly coupled various N-substituted imidazoles, which display nucleophilic reactivity, with 2-bromo-oxazolines to give the imidazolium precursors (Scheme 15.15) [55]. This direct condensation of an oxazoline and an imidazole salt provided a straightforward and modular route to the development of a new family of stereodirecting ligands. NHC - rhodium complexes could be obtained by reaction of the imidazolium salt with [ Rh(p-OtBu)(nbd))2] (nbd, norbornadiene) generated iw sifn [56]. 

The final restriction of simple columns stated earlier was that they should have a reboiler and a total condenser. It is possible to use materials fiow to provide some of the necessary heat transfer by direct contact. This transfer of heat via direct contact is known as thermal coupling. 

Azo-stilbene dyes formed by diazotization of a condensation product containing primary amino groups and coupling with azo dye coupling components, eg. Direct Brown 29 (Cl 40505) (6) ... 

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