Preparations and X-ray Structures of Compounds Containing the Four-Membered PN2Te Ring

Abstract

The reaction of Li[Ph2P(NSiMe3)2] with TeCU in a 1:1 molar ratio in CH2CI2 at -78 °C, followed by warming to 23 °C, produces Pl^PCNSiMesUTeCU (1) in essentially quantitative yield. An X-ray analysis shows 1 to contain a four-membered PN2Te ring with Te-N bond distances of 2.056(3) and 2.185(3) Á. When the same reaction is carried out in a 2:1 molar ratio, the product is Ph2P(NSiMe3)2Te(Cl)NPPh2NSiMes (2), which consists of a PN2Te ring with Te-N bond distances of 2.108(3) and 2.275(4) Á and a short exocyclic tellurium-nitrogen bond of 1.922(4) Á. Crystals of 1 are monoclinic, of space group P2\!n, with a = 15.494(7) k, b = 11.580(9) Á, c = 15.823, ß = 96.46(3)°, V = 2820(2) Á3, and Z == 4. The final R and Rw values were 0.024 and 0.027, respectively. Crystals of 2 are triclinic, of space group PI, with a = 12.372(7) k,b= 17.040(6) k,c= 11.648(4) Á, a = 108.11(2)°, ß = 109.32(4), = 88.76(4)°, V = 2193(2) Á3, and Z = 2. The final R and Rw values were 0.036 and 0.037, respectively.

Conformations and Energetics of Sulfur and Selenium Diimides

“…31 The analogous tellurium diimides have been observed to undergo a facile [2+2] cycloaddition with the formation of thermally stable dimers RNTe(µ-NR)2TeNR. [34][35][36] A similar [2+2] cycloaddition has also been observed between Se(N t Bu)2 and t BuNSeO. 37 Sandblom et al 28 have reported a DFT study of the conformations and dimerization energies of E(NMe)2 (E = S, Se, Te).…”

A survey of tellurium-centered secondary-bonding supramolecular synthons

“…Within this set, there are fifteen structures with Te-D SBIs shorter than 80% of the sum of r vdW (Table 2) and in each case the actual supramolecular synthon is the virtual four-membered heterocycle [Te-D] 2 . Six of these crystal structures (1,2,5-telluradiazole (32) [64], phenanthro(9,10-c)-1,2,5-telluradiazole (33) [65], 4,6-di-t-butylbenzo-2,1,3-telluradiazole (37) [44], benzo-2,1,3-telluradiazole (38) [66], 4,7-dibromobenzo-2,1,3-telluradiazole (39) [66], and the DMSO adduct of 4,7-dibromobenzo-2,1,3-telluradiazole (26) [66]) feature the synthon [Te-N] 2 assembled by 1,2,5-telluradiazole heterocyclic building blocks. The corresponding SBIs are very short; the same is observed for the SBIs in [Te D] (Table 1) formed by 1,2-tellurazole heterocycles, 6 [67] and 12 [54].…”

“…Hydrogen atoms have been omitted for clarity. Original data from Refs [40][41][42][43][44][45][46][47][48]…”

The supramolecular chemistry of 1,2,5-chalcogenadiazoles

“…Unexpectedly, an attempt to prepare a tellurium diimide by reaction II resulted in the formation of a benzotelluradiazole. The simplest method, III, is the reaction of an aromatic vicinal diamine with TeCl 4 [16]. In an early report [17] the attempted preparation of benzo-2,1,3-telluradiazole from o-phenylenediamine afforded a thermally unstable product; our own experiments identified this material as the result of incomplete deprotonation, C 6 H 4 (NH) 2 (TeCl 2 ), which was transformed by addition of an ancillary base into the desired compound in high yield.…”