Intercalation local environment

Both the V and Li NMR spectra show multiple vanadium and lithium local environments for the as-synthesized material x = 0.15), and the spectra cannot be explained by using a simple model based on the number of crystallographically distinct vanadium sites. On Li-ion intercalation, the V resonances sharpen and shift to higher frequencies (Figure 15) three sharp resonances along with two broader resonances are clearly resolved for the samples prepared at potentials of 3.4 and 3.0 V (x = 0.3 and 0.5, respectively). This behavior is consistent with solid—solution behavior in this potential range and is ascribed to the presence of localized defects at X close to 0 and electron delocalization for 1 > x > 0.05. Three lithium sites were observed in the Li... 

Lithium intercalation in VeOis has been studied by Stallworth et al. ° Variable-temperature Li NMR indicated considerable mobility for Li+ in the intercalated materials. The Li NMR data were compared with ESR spectra and near-edge X-ray absorption fine structure (NEXAFS) data on the same materials, and a correlation between vanadium oxidation state (from NEXAFS data) and NMR shift was observed. The authors explained the shifts in terms of different coupling mechanisms between the and shifts. The shifts were, however, extracted from static NMR experiments, and it is possible that some of the different local environments, typically revealed in a MAS spectrum, were not seen in this study. 

Since square planar platinum(II) complexes have vacant coordination site at the platinum atom, upon intercalation with DNA base pairs, the local environment around the Pt core changes and the mobility of the complexes decreases. Subsequently, a profound impact upon the photoluminescent properties can be envisioned. 

For stationary powders, the various spectra of intercalated species will relfect their mobilities while MAS and CP/MAS spectra will be useful for investigating their structures and local environments. 

Thus, it has been shown in this paragraph, that high-resolution H and Al solid-state NMR is a powerful tool for the characterization of a quality of the synthesized organo-LDH, in terms of degree of order, intercalation behavior, and preservation of the local environment in the metal-hydroxide network after chemical modification. 

Layered titanium phosphates have many potentially important applications in ion exchange, catalysis, intercalation, and sorption. Characterization of metal local environments by solid-state " /" Ti NMR has been difficult. In this work, the local structures around Ti in several representative layered systems, including alpha-, beta-, and gamma-TiP have been characterized, by examining the static NMR spectra of these ma-... 

A similar modulating effect of cholesterol on the location of the local anesthetic tetracaine has been observed recently (5). The uncharged form of the tetracaine molecule intercalates deeply into DHPC bilayers in the gel state and is displaced to an environment close to the lipid-water interface by increasing the hydrostatic pressure, in other words, by increasing... 

As described in the previous section, we incorporated Et as an artificial DNA base at specific sites in duplex DNA (Fig. 12.12) [44-46]. Temperature-dependent absorption and steady-state fluorescence measurements prove the intercalation of the Et moiety in duplex DNA [44], The intercalation properties of the Et moiety do not depend significantly on the local duplex environment. Interestingly, the optical properties of Et seem not to interfere with the presence of the different counterbases T, G, C or A [45]. This result is remarkable with respect to the steric demand of the Et heterocycle and indicates a bulged position of the counterbase. 

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