NMR INADEQUATE

Hensley ei al.,n reported the only direct experimental observation of head-to-head linkages in PS by 2D INADEQUATE NMR on, 3C-enriched PS. The method did not enable these groups to be quantified with sufficient precision for evaluation of W tc- Zammit el a/.130 studied chain distribution of low molecular weight PS prepared with AIBN initiator by MALDI-TOF. Separate distributions of chains formed by combination and disproportionation were observed. They estimated kJkK. at 90 °C to be 0.057. 

Summary Many cyclic and linear transition metal-silicon compounds have been obtained by the elimination of alkali halides. The structures of these complexes were determined by INEPT and INEPT-INADEQUATE NMR spectroscopy. 

The connectivity in 139 was also successfully analyzed using 2-D 29Si-29Si INADEQUATE NMR spectro-... 

Figure 19 2D INADEQUATE NMR spectrum of knipholone in (CD3)2CO isolated after administration of [13C2]-labelled acetate to Kniphofia pumila. The incorporation pattern of the intact [,3C2] units is marked by thick lines the only such unit that has remained unproven is marked by a dashed thick line. From Ref. 68, reproduced by permission of the American Chemical Society.

In order to conclusively determine the chemical shift of each carbon type in C706-, a 2D INADEQUATE NMR experiment was performed on a carbon-13 enriched fullerene102. This experiment correlates between the 13C NMR absorption of a carbon to that of its bonded neighbor. 

T. Asakura, M. Demura and T. Hayashi, NMR Assignments of Polyolefins and Olefine Copolymer Based on the C NMR Chemical Shift Calculation and 2D-INADEQUATE NMR. Annual Reports on NMR Spectroscopy. Academic Press, London, 1993. 

The substitution pattern is recognizable by the Si-2D-INEPT-INADEQUATE-NMR spectra (Fig. 3). 

Si INEPT-INADEQUATE NMR spectroscopy afforded further evidence for the nortricyclene structure of 7 as the coupling constants (Fig. 4) are consistent with the proposed atom arrangement. 

FIGURE 7.18 CPMAS NMR spectrum (upper), expansions of the aliphatic regions of the INADEQUATE NMR spectrum (middle) and HETCOR spectrum (lower)... 

Fig. 40. (cont.) Pure siliceous ferrierite. (c)RT Si MAS INADEQUATE NMR spectrum [94M4]. (d) Temperature dependences of the isomer shifts [04D1]. 

COSY, NOESY and HETCOR NMR spectroscopies. The H and NMR chemical shifts of 3-PPA (C9H13N) were calculated by means of the Hartree-Fock (EIF), Becke-Lee-Yang-Parr (BLYP) and Becke-3-Lee-Yang-Parr (B3LYP) density functional methods with 6-311 -I- -I- G(d, p) basis set, respectively. The Fl, proton coupled and uncoupled N, DEPT, COSY, HETCOR, INADEQUATE NMR spectroscopies for 1,7-diamino-heptane and its magnitude of one bond coupling constants of... 

An analysis of the 2D-INADEQUATE NMR data performed by Yamada et al. for enriched Sc2 C66 fullerene has shown that this compound contains a C2v(4059)-C66 cage consisting of two sets of unsaturated linear triquinanes (ULTs), in which three pentagons abut one another and two scandium ions are located within the folds of each of the ULT units. Conclusive structural elucidation has been accomplished by single crystal XRD. 

D-INADEQUATE NMR has been developed as a reliable method to determine the connectivity of carbon atoms [55-57]. By using this method, Hikichi and coworkers [44] confirmed the validity of the chemical shift assignments of various types of carbons in a stereoirregular ethylene-propylene (E-P) copolymer proposed by Randall [40]. The pentad comonomer sequence assignments of methane carbon resonances in stereoregular E-P copolymer have been provided from the connectivities between methane and methyl carbons [57]. 

Figure 43 (a) Expansion of the a-carbon region from the 2D-iNADEQUATE NMR spectrum of low-MW poiy(a- C-styrene)... 

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