M,n-ADEQUATE experiments

A further detractor from the m,n-ADEQUATE experiment is the inherent ambiguity of the two long-range magnetization transfers. As in the HMBC/GHMBC experiment, the m/ci 1 transfer step may afford... 

Aside from the initial applications of the n, 1- and m,n-ADEQUATE experiments in the elucidation of the structure of 5,6-dihydrolamellarin (3, see Sections 4.1, 5.1 and 6.5), the author is unaware of any reported applications of these experiments in the literature.38 Given the potential ambiguities associated with the two long-range magnetization transfer steps of the latter, coupled with the very low sensitivity and the fact that correlations are observed in Fi at the DQ frequency of the coupled carbons rather than at the 13C shift as in the 1,1- or 1,h-ADEQUATE experiments, it is probably quite likely that the m,n-ADEQUATE experiment will continue to be very sparingly utilized for structure elucidation. 

The long-range delays mJcn and /cc were optimized for 69 and 44 ms, respectively, which correspond to 7.25 and 11.4 Hz, respectively. The authors did not report the digitization or the acquisition time for the m,n-ADEQUATE experiment. 

Several variations of the ADEQUATE experiment are possible. We will begin with the 1,1-ADEQUATE experiment, which exploits 1Jcn and 1/cc couplings to allow for the identification of adjacent neighbour carbons. Other variants of the experiment are 1, n-, n, 1-, and m,n-ADEQUATE 40 The schematic representation of the magnetization transfer in the various types of ADEQUATE experiments is shown in Figure 1. 

Consider, now, a second example where the response from the experiment can be adequately modeled by a model that contains linear terms in the design variables, x, and the environmental variables, z, and also cross-product terms xz. Therefore, if there are n design variables, x, x, .. ., x, and m environmental variables, z, z, .. ., z, then the response, y, can be represented by... 

A. N. Prokunin and M. L. Fridman 23 24) seem to be the first investigators to have done the first adequately accurate calculations of power-function fluid helical flow in a circular (tubular) head with a rotary core. At the same time a series of experiments... 

Of the set of experiments carried out, one using cyc/o(-L-[,5NJPhe-L-[ l-I3C]Phe) (117) is the most notable and informative. Incorporation of the precursor into (115) was examined by 13C n.m.r. spectroscopy. The spectrum of (115) showed enrichment of the carbonyl signal of the dioxopiperazine moiety, and of this one only. Further, this signal was split by the adjacent 15N label, establishing that there is (essentially) intact incorporation of the precursor. In the feeding experiment, the labelled precursor was administered together with unlabelled dipeptide, to ensure that the labelled and the unlabelled phenylalanine that could have been formed would have been adequately mixed before recombination. 

Carbocation Intermediates.—Though the nature of the active centres in polymerizations propagated by carboanions has been well known for some time, and reasonably adequately characterized, the corresponding species in cationic propagations has proved difficult to identify with anything like the same certainty. However, the use of super acid media, e.g. FSOaH/SbFj, has now enabled Olah to obtain a n.m.r. spectrum of the elusive styryl carbocation, following experiments such as that in which a racemic mixture of products was obtained from the reaction of (—)-l-phenylethyl chloride with EtaAl, which provided powerful circumstantial evidence for the existence of the ion. More recently a particular definitive paper on and n.m.r. spectra of styryl species has appeared. 

Usually, C is assumed to depend on polymer mass concentration c and temperature T, unless the chain is too short. It can be adequately formulated by free volume theory [3]. On the other hand, Fg is assumed to be a function of c and N (or molecular weight M). The central theme in polymer self-diffusion studies is to evaluate the latter by theory or experiment for a variety of chain architectures and solvent conditions. 

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