Synthesis, characterization, and ligand behaviour of a new ditelluroether (CH)Te(CH)Te(CH) and the concurrently formed ionic [(CH)Te(CH)]Br.

The reaction of 1-naphthyl bromide with n-butyl lithium, elemental tellurium, and 1,4-dibromobutane in THF affords both (CH)Te(CH)Te(CH) (1) and [(CH)Te(CH)]Br (2) in good yields. 1 is preferentially formed at low temperatures and is a rare example of a structurally characterized ditelluroether in which the tellurium atoms are bridged by a hydrocarbon chain. In the solid state, 1 shows secondary bonding TeTe interactions, which connect the molecules into layers which are further linked to 3-dimensional frameworks by TeH hydrogen bonds. [(CH)Te(CH)]Br (2) is formed concurrently during the synthesis of 1 and is the main product, when the reaction is carried out at room temperature. The revPBE/def2-TZVPP calculations of the reaction profiles indicate that the formation of 2 is somewhat more favourable than that of 1. Furthermore, at room temperature the activation energy for the formation of 2 is lower than that of 1. At low temperatures the activation energy of the reaction leading to 1 is lower than that to 2, which is consistent with the synthetic observations. When 1 was treated with CuBr, [Cu(μ-Br){μ-(CH)Te(CH)Te(CH)}] (3) was formed. It crystallizes as two polymorphs (3a) and (3b) in which both the packing and the conformation of the ditelluroether ligands are different. The reaction of 1 with HgCl produces [(CH)Te(CH)][HgCl]·CHCl (4·CHCl) and that of 1 with CuCl affords [(CH)Te(CH)]Cl (5). 2 and 5 are isomorphous.