The effect of changes in the relative orientation of vicinal and geminal 13C and 1H nuclei, and in the disposition of adjacent substituents, on coupling between these nuclei has been examined with a variety of 13C-labelled carbohydrates. Compounds synthesized for this purpose include derivatives of D-glucose-1- and -6-13C and L-idose-6-13C, and related lactones, and the measurements have been made with p.m.r. spectra of these compounds. Vicinal 13C-1H coupling, both through C—C and C—O bonds shows an orientational dependance analogous to that for protons: i.e., dihedral angles of 60–100° are associated with smaller coupling (0–3 Hz) than angles of 140–180° (4.5–5.5 Hz); sp2 carbon produces splittings of almost twice these values. The observed spacing is smaller when an oxygen atom is in the plane of the coupling pathway than when out of plane, both for vicinal and geminal 13C–1H interactions, and the presence of an extra oxygen also may have a notable impact on the geminal interaction. A study of rotational isomerism in these compounds indicates that the characteristics of coupling between 13C and 1H nuclei may fruitfully be compared with those of H–H coupling in the analysis of such dynamic systems.

Signs of two bond (2J) 13C–1H coupling in 13C–enriched carbohydrates have been determined from proton spectra by the double irradiation technique. Instances of both positive and negative 2J values are given and are characterized in terms of the relative orientations of the coupled proton and of oxygen appended to the 13C nucleus; e.g., an oxygen anti to the proton appears to make a positive contribution to 2J and a gauche oxygen a negative one. Theoretical calculations, using ethanol and 1,1-ethanediol as model compounds, are in accord with these experimental observations.

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This article summarizes our experience at McGill University in developing a strong connection not only with a large number of students but also with the general public. This has led to the establishment of a cooperative team to deliver useful information about chemistry and science broadly via the radio, television, the Internet, lectures, articles, and courses.

There is little disagreement that many more nonscientists should be exposed to science courses (1). The significant question is how to approach the problem. One characteristic of virtually all courses in chemistry that have been designed for nonscientists has been the inclusion of lecture material with sections of traditional, introductory chemistry (2). While there can be no serious quarrel with this approach, we feel that a great deal of important information, along with a number of chemical principles, could be taught in an alternative fashion (3).We were particularly interested in building a university audience which would include science majors as well as the nonscience students. It is our contention that science/chemistry majors do not normally have time in their course programs to learn much about the modern chemical aspects of food, nutrition, drugs, or the issues that confront us all in the daily press. We believe that it is possible for a chemistry major to be exposed to a variety of important topics such as air and water pollution, household chemistry, and energy issues at a reasonably sophisticated level that still would be understandable to a nonscience cohort (4).