Intercalating reagent

Therefore, graphite is preferable in a supported reaction, although the use of intercalated reagents remains possible. 

For detection of DNA fragments, Fe(phen)32+ was used as the electrochemi-cally active intercalation reagent. The constant background current from free Fe(phen)32+ decreased in the presence of the DNA-Fe(phen)32+ complexes. Therefore, this is an indirect amperometric detection method. It was found that a distance of 300 pm, instead of 600 pm, between the working electrode and reference electrode has produced less electrical interference (in the form of a sloping baseline), allowing the use of a separation voltage up to 1200 V (240 V/cm) [745]. 

Intercalated reagent. Melin and Herold have reported the preparation of C24SbCls as black platelets with considerable stability to air. Kagan et al. find that intercalated SbCls differs considerably in reactivity from ordinary SbCls. It reacts with alkyl bromides, iodides, and tosylates to give the corresponding alkyl chlorides. It does not effect aromatic chlorination. In contrast, ordinary SbCls reacts with alkyl bromides to give a-chloro bromides and readily chlorinates aromatic compounds. 

It is used as a fluorinating reagent in semiconductor doping, to synthesi2e some hexafluoroarsenate compounds, and in the manufacture of graphite intercalated compounds (10) (see Semiconductors). AsF has been used to achieve >8% total area simulated air-mass 1 power conversion efficiencies in Si p-n junction solar cells (11) (see Solarenergy). It is commercially produced, but usage is estimated to be less than 100 kg/yr. 

Xenon difluoride may be used as the pure reagent or as a graphi te intercalate for the effective fluonnation of polynuclear aromatics [86 87] (equations 49 and 50)... 

Xenon difluoride [55], xenon difluoride complexed with dialkyl sulfides [59], and xenon difluoride intercalated with graphite [90] are all effective reagents for the fluonnalion of acids, enolates, or enols (Table 2)... 

One of the first applications developed for flow cytometry was cell cycle analysis.2 There are numerous intercalating fluorescent DNA and RNA staining reagents that can be used to determine the amount of DNA in cells, an indicator of cell cycle stage and progression, as demonstrated in Figure 7.3. Nucleic acid dyes may be selective for DNA... 

Two examples of aquation/anation studies of chloro-platinum(II) complexes of possible medical relevance appeared in subsection 1 above 202,207). Aquation of cisplatin is slower in the presence of DNA but not in the presence of phosphate 220). DNA also inhibits substitution in [Pt(terpy)(py)]2+ and related complexes. For reaction of these charged complexes with iodide ion inhibition is attributable to electrostatic interactions - the complex is concentrated on the double helix and thus separated from the iodide, which distances itself from the helix. Intercalation of these complexes within the helix also serves to make nucleophilic approach by neutral reagents such as thiourea more difficult 221). 

Another reagent, hexamethylenetetramine (HMT) has also been used in place of urea for the homogeneous preparation of LDHs. HMT hydrolyzes at high temperature in aqueous solution with the release of ammonia, which makes the solution alkahne, and formaldehyde, which would not be expected to be incorporated into the LDH. Using HMT, well-crystalhzed 1-5 p.m -sized particles of chloride-intercalated LDHs were prepared in a pressure... 

Complexes with less extended aromaticity such as Ru(bpy/phen)2HAT [73-76] (HAT = 1,4,5,8,9,12-hexaazatriphenylene, Fig, 2) and Ru(bpy)2PPZ [77-80] (PPZ = 4,7-phenanthrolino-[6,5-b] pyrazine. Fig. 2) exhibit also characteristics most relevant to intercalation. We can mention (1) a very slow mobility of the HAT complex along the DNA double helix [81], (2) a good protection of the complex versus reagents that remain in the bulk solution [73,79], and (3) a clear hypochromic effect on the MLCT transition in the presence of DNA [73, 75, 79,80]. 

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