A nationwide planning of Analytical Chemistry in universities: Possibilities and problems

Summary A nationwide planning of Analytical Chemistry in universities should meet two requirements: formulation of a common minimum programme for all universities and a well-balanced spread of research themes over the different universities. In the Netherlands this planning is the object of ISOAN, the Intersubfaculty Deliberation on Analytical Chemistry. Perhaps spectacular results have not yet been obtained, however thinking about these subjects has led to a more lucid picture and better mutual understanding.Presented at Euroanalysis III conference, Dublin, August 20–25, 1978     

The 9-barbaralyl cation, 1,4-bishomotropylium ion and some related C9H9 carbocations : Electronic structures, stability and reactivity

The electronic structures of the 9-barbaralyl cation(1), the 1,4-bishomotropylium ion (5) and some related C₉H₉⁺ isomers have been studied byab initio STO-3G calculations. The stability of the cyclopropylcarbinyl cation 1 and the homoaromatic ion 5 as compared with their allylic counterparts is explained in terms of delocalization and MO interactions between molecular fragments. Both the symmetry of, and the distance between, molecular fragments are of importance for the electronic structure, and even symmetry-allowed interactions are negligible in the absence of favourable geometrical distortions. The non-classical ion 3 with D_3h symmetry presents special problems where other factors, such as strain, are important for the total energy. A choice between proposed mechanisms for the degenerate rearrangements of 1 can now be made with confidence.