中文名称 | 英文名称 | CAS号 | 化学式 | 分子量 |
---|---|---|---|---|
—— | 1,3-di-tert-butylimidazolidine | 224453-32-1 | C11H24N2 | 184.325 |
Frustrated Lewis pairs consisting of N-heterocyclic carbenes (NHC) and the borane B(C6F5)3 react with elemental sulfur or selenium to give products of the type NHC-E-B(C6F5)3, where E is S or Se. Three such products, two with sulfur and one with selenium, were characterized by X-ray diffraction and shown to exhibit considerable conformational flexibility, as revealed by differing torsion angles in the atom sequence N-C-E-B-Cipso-Cortho. In the sulfur derivatives, the S-B bonds are all long (ca. 2.05 Å), and the C-S bonds (ca. 1.73 Å) are clearly lengthened compared to imidazole-2-thiones. The Se-B distance of 2.2111 Å is the first selenone-borane bond length to be determined by X-ray analysis.