Abstra~t--'~C chemical shifts and 1J(14N-13C) coupling constants as well as stretching frequencies of the isocyano group are reported for some representative aliphatic, unsaturated and aromatic isocyanides and for two copper(1) isocyanide complexes. The results are discussed in terms of the inductive and mesomeric substituent effects on the polarisation and charge density of the C-N=C bonds. The marked solvent effect on the chemical shifts of the isocyano carbon hampers comparison of our data with previously reported data. The hydrogen bonding shift of this carbon in water or methanol is much smaller than previous data suggest.

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Abstract-The complete interpretation of 220 MHz PMR spectra and the accurate chemical shifts and coupling constants, obtained after computer simulation of the spectra, of a number of TMS-mono and -disaccharides are given. By means of an adapted Karplus equation the conformation of the derivatives has been studied in detail. All pyranose rings are found to occur in the Cl(D) chair conformation. As a consequence of their greater steric requirement, the OTMS groups deform the chair conformation more than the OAc groups. The preferred conformation of the C-5-CH,OTMS group is determined and found to be dependent on the configuration at C-4.

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The 13C-(25.16 MHz) and 'H-n.m.r. (220,300 MHz) spectra of permethylated mannopyranoses, their 6-deoxy analogues, and permethylated 6_deoxy-ghrco-and