New Series of Intramolecularly Coordinated Diaryltellurium Compounds. Rational Synthesis of the Diarylhydroxytelluronium Triflate [(8-Me₂NC₁₀H₆)₂Te(OH)](O₃SCF₃)

Abstract

The reaction of 8-dimethylaminonaphthyllithium etherate with the tellurium(II) bis(dithiocarbamate) Te(S 2 CNEt 2 ) 2 provided the diaryltelluride (8-Me 2 NC 10 H 6 ) 2 Te (1). The oxidation of 1 with an excess of H 2 O 2 did not afford the expected diaryltellurium(IV) oxide (8-Me 2 NC 10 H 6 ) 2 TeO ( 2), but the diaryltellurium-(VI) dioxide (8-Me 2 NC 10 H 6 ) 2 TeO 2 (3). The preparation of 2 was achieved by the comproportionation reaction of 1 and 3. The protonation of 2 using triflic acid gave rise to the formation of diarylhydroxytelluronium triflate [(8-Me 2 NC 10 H 6 ) 2 Te(OH)]-(O 3 SCF 3 ) (4), which features the protonated diaryltellurium oxide [(8-Me 2 NC 10 H 6 ) 2 Te(OH)] + (4aand 4 were characterized by X-ray crystallography. The experimentally obtained molecular structures were compared to those calculated for 1−3, 4a, and (8-Me 2 NC 10 H 6 ) 2 Te-(OH) 2 (5) as well as the related diphenyltellurium compounds Ph 2 Te (6), Ph 2 TeO (7), Ph 2 TeO 2 (8), [Ph 2 Te(OH)] + (9a), and Ph 2 Te(OH) 2 (10) at the DFT/B3PW91 level of theory.

Diarylhalotelluronium(iv) cations [(8-Me2NC10H6)2TeX]+ (X = Cl, Br, I) stabilized by intramolecularly coordinating N-donor substituents

“…Compounds 7·Cl − , 7·Br − , 7·I − and 7·I 3 − containing the diarylhydroxytelluronium cation 7 are soluble in at least moderately polar solvents. The 1 H, 13 C and 125 Te NMR spectra (CDCl 3 or CD 3 CN) compare well with those of 7·O 3 SCF 3 − , 9 and are consistent with an ionic structure in solution. However, in CDCl 3 the chemical shifts for 7·Cl − (1187.6) and 7·Br − (1176.4) are slightly different, which apparently suggests some degree of association between the diarylhydroxytelluronium cation 7 and counterions.…”

“…Te⋯N bond length of (8-Me 2 NC 10 H 6 ) 2 Te (2.763(4) Å). 9 The molecular structure of the diarylhydroxytelluronium cation 7, isolated as 7·O 3 SCF 3 − , was already discussed in detail in our preceding paper. 9 The same cation [(8-Me 2 NC 10 H 6 ) 2 TeOH] + (7) with very similar structural parameters is present in the crystals of 7·Cl − , 7·Br − ·H 2 O·THF, 7·I − , 7·I 3 − ·H 2 O.…”

“…9 The molecular structure of the diarylhydroxytelluronium cation 7, isolated as 7·O 3 SCF 3 − , was already discussed in detail in our preceding paper. 9 The same cation [(8-Me 2 NC 10 H 6 ) 2 TeOH] + (7) with very similar structural parameters is present in the crystals of 7·Cl − , 7·Br − ·H 2 O·THF, 7·I − , 7·I 3 − ·H 2 O. However, unlike 7·O 3 SCF 3 , the latter compounds reveal significant Te⋯Y interactions (Y = Cl, Br, I) between the cations and halide anions, which might be the reason for the colour of these compounds that presumably arise from charge transfer transitions.…”

Synthesis and structure of diarylhalotelluronium hexahalotellurates [(8-Me2 NC10 H6)2 TeX]2 TeX6 (X=Cl, Br)

“…Bis(8-dimethylaminonaphthyl)telluride was prepared according to literature procedure (Beckmann et al, 2012). The 1 H, 13 C and 125 Te NMR spectra were recorded using the Jeol GX 270 and Varian 300 Unity Plus spectrometers and were referenced to SiMe 4 ( 1 H, 13 C) and Me 2 Te ( 125 Te).…”

“…Recently, we reported on a series of diaryltelluronium compounds [(8-Me 2 NC 10 H 6 ) 2 TeX]Y (X = Cl, Br, I, OH; Y = Cl, Br, I, I 3 , PF 6 , O 3 SCF 3 ) in which two intramolecularly coordinating 8-dimethylaminonaphthyl substituents gave rise to cationic structures (Beckmann et al, 2012(Beckmann et al, , 2013.…”