A linear homocatenated compound containing six indium centers.

In contrast to carbon and its heavier congeners, group 13 elements are rarely observed to catenate into linear chains. Here, we find that treatment of indium(I) iodide with a protonated N-xylyl beta-diketiminate and a strong potassium base in tetrahydrofuran yields a hexa-indium chain. X-ray crystallography revealed one beta-diketiminate ligand bound to each indium center with no bridging ligands supporting the five indium-indium single bonds. The terminal indium centers were capped with iodine. Electronic spectroscopy and computations on a model compound offer preliminary support for sigma delocalization along the chain.