A Distibene with Extremely Long Sb=Sb Distance and Related Heavier Dipnictenes from Salt‐Free Metathesis Reactions

Abstract

Conversions of organoelement diamides, Ar^DippE(NMe₂)₂ (E=Sb, Bi; Ar^Dipp=C₆H₃‐2,6‐Dipp₂), with Ph₂SnH₂ as reducing agent gave access to low‐valent, heavier group 15 dimers Ar^DippSb=SbAr^Dipp and Ar^DippBi=BiAr^Dipp, while only readily removable byproducts (i. e. dihydrogen, amines) and cyclo‐(Ph₁₂Sn₆) are generated during the reaction. Moreover, experiments involving the reaction of organoantimony hydride species Ar*₂SbH (Ar*=C₆H₂‐2,6‐(Ph₂CH)₂‐4‐iPr) with Bi(NEt₂)₃ yielded a second novel distibene, Ar*Sb=SbAr*, with the currently longest Sb−Sb bond distance of 2.8605(5) Å in a distibene. In conversions of TbbSnH₃ (Tbb=C₆H₂‐2,6‐(CH(SiMe₃)₂)₂‐4‐tBu) with Bi(NEt₂)₃, ligand migration resulted in the isolation of TbbBi=BiTbb. Remarkably, the herein reported novel inorganic coupling route enables preparation and isolation of heavier dipnictenes without the formation of inorganic salts. All four low‐oxidation state compounds were isolated and subsequently characterized using state of the art techniques, i. e. X‐ray crystallography, NMR and UV/Vis spectroscopy.