Department Seminar - Risto Laitinen, University of Oulu, Monday, November 28, 2022, 1:30-2:30
We are pleased to welcome Dr. Risto Laitinen of the University of Oulu (Finland) for a department seminar.
*Note some differences from our usual seminar setup
Title: Formation of Sulfur and Selenium Imides via Cyclocondensation
Date: *Monday, November28, 2022
Room: *ABB 270
Host: Gary Schrobilgen
Abstract: Cyclocondensationis an important route for inorganic heterocycles involving in particular a Group 15 or 16 element linked to nitrogen.1 For instance, the reactions between primary amines and SCl2 or S2Cl2afford the eight-membered ring, 1,3,5,7-S4(NMe)4,2 orthe six-membered ring 1,4-S4(NR)2,3respectively. By contrast, a complicated mixture of products is formed upon cyclocondensation of tBuNH2 with SeCl2. Avariety of cyclic selenium imides with the ring sizes 6-8 and 15, as well as the acyclic imido selenium dichlorides ClSe[N(tBu)Se]nCl (n = 1-3), have been isolated from these mixtures and identified by a combination of 77Se NMR spectroscopy and single crystal XRD.4 The product distribution is dependent on the molar ratio and the concentration of the reagents. ClSe[N(tBu)Se]2Clhas been found to be a bifunctional reagent and concurrently affords 1,3-Se3(NtBu)2and 1,3,5-Se3(NtBu)3 upon treatment with tBuNH2in THF. Cyclic selenium imides are generated from this acyclic precursor either by reduction and/or by nucleophilic substitution. Thus, the imidoselenium dichlorides are probable intermediates in the formation of the cyclic selenium imides from tBuNH2 and SeCl2.
1. Chivers, T., Laitinen, R. S., Dalton Trans 2017, 46, 1357-1367, and references therein.
2. (a) Stone, B. D., Nielsen, M. L., J. Am. Chem. Soc. 1959,81, 3580. (b) Macdonald, A. L., Trotter, J., J. Can. Chem. 1973, 51, 2504.
3. Woollins, J. D., Williams, D. J., Jones, R., Angew. Chem., Int. Ed. 1985,24,760.
4. Chivers, T.,Laitinen, R. S., Chalcogen-Nitrogen Chemistry. From Fundamentals to Applications in Biological, Physical and Materials Sciences, Updated Ed., World Scientific: Singapore 2022, 450 pp.