Abstract
TeI~2~(CH~2~SiMe~3~)~2~(1), TeI~2~Th(CH~2~SiMe~3~ (2), TeI~2~Ph(CH~2~SiMe~3~)(3), and TeI~2~Th~2~(4) (Th = 2‐thienyl) were synthesized in excellent yields from the corresponding tellanes and I~2~. The products were characterized by ^125^Te NMR spectroscopy and single crystal X‐ray crystallography. Each TeI~2~RR′ molecule shows a trigonal bipyramidal coordination around tellurium with the iodine atoms occupying axial positions, and the organic groups and the lone pair occupying equatorial positions. The TeI bonds and the ITeI angles in 1–4 span a range of 2.8407(9)–3.0194(10) Å and 171.85(2)–175.71(2)°, respectively. The TeC bonds and CTeC angles show respective ranges of 2.100(6)–2.136(7) Å and 95.1(3)–100.9(3)°. In the solid state, the molecules show a varying degree of secondary bonding interactions. With the exception of TeI~2~(CH~2~SiMe~3~)~2~ (1), the compounds show Te···I or I···I secondary bonding interactions leading to supramolecular assemblies. TeI~2~Ph(CH~2~SiMe~3~) crystallizes as two polymorphs. One (3a) is isomorphic with TeI~2~Th(CH~2~SiMe~3~) (2). The other (3b) shows a lattice of two alternating layers of molecules. In one layer, the molecules are linked into a two‐dimensional network by Te···I and I···I interactions whereas the second layer consists of discrete dimers. The strongest Te···I secondary bonding interactions are observed for TeI~2~Th~2~. The lattice is composed of tetramers that is reminiscent of those in γ‐ and δ‐TeI~4~ and also have precedent in TeI~2~RR′ species. The structures of TeI~2~Me~2~ and TeI~2~Ph~2~ have been considered for comparison. The trends in ^125^Te NMR chemical shifts in TeI~2~RR′ (R, R′ = Me, CH~2~SiMe~3~, Th, Ph) are also discussed. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:348–357, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20688