RESUMO
Compounds with multiple bonds between elements of the second and fifth periods are extremely unstable, and systematic investigations into their properties remain elusive. Herein, we report a tellurium-centered heteroallene that contains multiple bonds between carbon and tellurium. This compound is the first example of bis(methylene)-λ4-tellane, which was synthesized and fully characterized using multinuclear NMR spectroscopy and X-ray crystallography. In the solid state, this λ4-tellane exhibits a bent allene structure for the CâTeâC moiety and unsaturated Te-C bonds. Interestingly, the allene-type structure is retained in the solution, which is reflected in an absorption band due to the π-π* transition at 610 nm. This λ4-tellane also exhibits unique reactivity toward dihalogermylenes, which yielded rare cyclic telluragermetanes.
RESUMO
The dinuclear (thio)(silyl)carbene and (seleno)(silyl)carbene gold(i) complexes 1 and 2 were obtained from the reaction of two equivalents of AuCl(SMe2) with the stable bis(methylene)-λ4-chalcogenanes 3 and 4, respectively. The reaction proceeds under elimination of the chlorosilane moiety of 3 and 4. Complexes 1 and 2 were characterized by spectroscopic and X-ray diffraction (XRD) analyses. The 13C NMR signals for the carbene centers of 1 (309 ppm) and 2 (345 ppm) are by more than 150 ppm downfield shifted relative to those for other known (NHC)AuCl complexes. These results indicate that (chalcogeno)(silyl)carbenes, like (amino)(silyl)carbenes, belong to the push-spectator family of carbenes.