Decoupling partial

B n.m.r. spectra of tetraborane(8) carbonyl at 32.1MHz have been interpreted to suggest the presence of two isomers (computer-line-narrowed, proton-decoupled, partially relaxed F.T. spectra were used). The two isomers were respectively endo- and exo- for the position of the CO group with respect to the folded ring, in the ratio of ca. 60 to 40. It was not possible to say whether the two isomers had been formed in the synthesis, and subsequently remained static, or whether the two forms were slowly interconverting. ... 

Fig. 13. Proton noise decoupled 25.2 MHz NMR spectrum of averufin (8) derived from [l,2- C]acetate. Spectral width 5000 Hz, pulse delay 1 sec 90° rf pulse (50 /isec) transients 20 K. Insert low power oflf-reasonance proton-decoupled partially relaxed spectrum. [From Gorst-Allman et al. (1977), 7. Chem. Soc. Perkin Trans. /, 2181-2188. Copyright permission from The Chemical Society, London.]...

Figure 2.9. NMR spectra of 3,4-dimethoxy-p-methyl-p-nitrostyrene (9) [CDCI3, 25 C, 20 MHz], (a, b) H broadband decoupled, (a) complete spectrum with CH3 quartets at Sc = 14.1 and 56.0 (b, c) decoupled and coupled partial spectrum of benzenoid and alkene carbon atoms, (c) obtained by gated decoupling...

Conditions (CD3)2CO, 25 °C, 200 MHz H), 50 MHz ( C). (a) //NMR spectrum with expanded sections (b,c) C NMR partial spectra, each with proton broadband decoupled spectrum below and NOE enhanced coupled spectrum above with expanded multiplets at 6c = 76.6 and 83.0. 

Figure 2. Partial 100 MHz P.M.R. Spectrum of 3,4,6-tri-O-acetyl-v-glucal (1) measured for a chloroform -d solution (A normal spectrum of the Hi and H2 resonances respectively (B) frequency sweep spin-decoupled spectrum of the Hi and H2 resonances, with a strong decoupling field centred on the Hs resonance (C), as in (B) above, but with an additional weak radiofrequency field centred on the high field transition of the H2 resonance (D), as in (B) above, but with a weak radiofreauency field centred on the low field transition...

It should be noted that it would have been totally impossible to have effected these decoupling experiments by the field-sweep method a>i has to be scanned ca. 100 Hz to observe the H2 resonances which of course would require < >2 to be scanned by an equal amount. Since it is not possible to obtain a decoupling field of this magnitude, the above experiment would merely result in partial decoupling of the H2 resonances. 

Fig. 5.—Proton-decoupled, C-N.m.r. Spectra (at 22.5 MHz) of the Partial-reductive, [ C]Methylation Studies of —1.5 mM Glycophorin in H2O at 30°. [Spectra of methylated...

These results demonstrate that side-chain liquid crystalline polymers can be synthesized by polymer analogous reactions from theoretically any polymer backbone. When the polymer backbone is rigid, as in the case of PPO, a long spacer is required both to decrease the Tg of the parent polymer and to partially decouple the... 

Find the gain matrix and show that the relative gain parameter is 1. Show how this partially decoupling scheme can be implemented as analogous to Fig. 10.13. 

C NMR of linear cross-linked PS. The proton decoupled 13C NMR spectra of linear and 1% cross-linked PS at 75 MHz in chloroform are illustrated in Figure 3. These spectra are similar to those for linear and cross-linked chloromethylated PS previously reported at lower field (14), although we have been able to resolve more structure in tHe" aliphatic and aromatic regions here. The quarternary and methylene carbon resonances at about 146 ppm and between 40 and 50 ppm respectively, are the most strongly affected by stereochemistry (20). The ortho and meta resonances at 128.4 ppm show partially resolved structure in the linear PS, as does the para carbon at 126.1 ppm. The methine resonance at... 

Whether you believe all that about my spreadsheet is not important here. Certainly, there are many times when performance, decoupling, or a partial spec leads to differences between model and code. So the reviewer is faced with trying to determine whether there is some correspondence between them whether the code conforms to the spec (or refines it). 

We need to decouple the design efforts on the different partial problems, so that we don t have to keep them all in our heads at once — or indeed, in any one head. 

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