Reaction of tellurium tetraiodide with 2,3‐dihydro‐1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene

Abstract

2,

Lewis Base Sequestered Chalcogen Dihalides: Synthetic Sources of ChX2 (Ch=Se, Te; X=Cl, Br)

“…The released dihalogen often participates in undesirable side reactions, leading to difficulty in controlling the reaction outcome. [3,4] The X 2 can be sequestered by the addition of a third species (i.e., cyclohexene, SnCl 2 ), provided the additional reagent does not interfere with the targeted reactions. [5,6] Within our laboratory we have found that starting with a Ch II source appears to largely circumvent this problem.…”

Tellurium(II)‐Centered Dications from the Pseudohalide “Te(OTf)2”

“…The Te-C distances in 10 (2.136(4), 2.138(3) Å) are consistent with single bonds as they display no shortening indicative of multiple bond character and are similar to other representative Te-C single bonds (≈ 2.10 Å). [10,19] This underscores the difference in structure from 12, in that 10 cannot be represented as an analogue of 12a, but is best drawn as a heavy element analogue of 12b ( Figure 5). …”

“…Unfortunately, these compounds readily undergo redox reactions in the presence of strong Lewis bases, often to the elemental form, precluding access to the target compounds. [7][8][9][10] Nevertheless, success in generating highly charged (dicationic) S and Se species has been achieved by utilizing low valent dihalides as the chalcogen source (SCl2 or SeCl2). [11] For tellurium, no stable binary dihalide reagents are known, thus developing the corresponding chemistry for this heavier congener has remained elusive.…”

“…2.10 ). [10,19] This underscores the difference in structure from 12, in that 10 cannot be represented as an analogue of 12 a, but is best drawn as a heavy-element analogue of 12 b (Figure 7). [13,20,21] There are only weak solid-state interactions with the oxygen atoms of the OTf anions of at least 2.74 , and the O atoms involved (O(1), O(2)) are distorted significantly outside the ideal square plane about the tellurium center.…”

Dicationic Tellurium Analogues of the Classic N‐Heterocyclic Carbene

“…[26,27] Coordination by Lewis bases allows for TeX 2 to be stabilized and stored. [28][29][30][31][32][33][34] Recently a few groups have used this strategy to deliver this otherwise unstable electrophilic Te II source. [35][36][37] Therefore, the proposed synthetic route to the tellurium NHC analogues is coordination by a DAB ligand to TeX 4 , followed by reduction and halide abstraction to give the dication.…”