First Isolation and Characterization of Sodium and Potassium Tellurocarboxylates: Structural Analysis of Te-Alkyl Telluroester.
The first synthesis and characterization of sodium and potassium tellurocarboxylates were achieved by the reaction of acyl chlorides with the corresponding alkali metal tellurides. The salts are yellow to red solids or oils. The aliphatic derivatives are very sensitive toward oxygen and very thermally sensitive. However, the aromatic derivatives are relatively stable and can be stored for 1 week below -5 degrees C and under oxygen-free conditions. The most practical method for the synthesis of Te-alkyl telluroesters was established by the reaction of the sodium and potassium tellurocarboxylates with alkyl iodides at 0 degrees C. The first X-ray structural analysis of telluroesters (RCOTeR') was carried out for Te-methyl 4-chlorobenzenecarbotelluroate (4-ClC(6)H(4)COTeCH(3)), whose crystals are monoclinic (P2(1)/a) with a = 5.975(3) Å, b = 14.517(2) Å, c = 10.617(3) Å, beta = 92.74(3) degrees, V = 919.8(4) Å(3), and Z = 4. The molecule was nearly planar. The C=O and C-Te bond lengths are 1.204(3) and 2.153(3) Å, respectively, indicating C=O double and C-Te single bonds. The C-Te-C angle of the C(O)TeCH(3) moiety is close to a right angle (92.3 degrees ), much more narrow compared with those [C-E-C, E = O (>105 degrees ), S (>102 degrees ), Se (>95)] of common esters and thio- and selenoesters (ArC(O)ER', E = O, S, Se; R' = alkyl). The nu(C=O) bands and the (13)C=O and (125)Te NMR spectra of the sodium and potassium tellurocarboxylates are discussed in comparison with those of other alkali metal or oxygen, sulfur, and selenium isologues.
Kato
Shinzi
S
Department of Chemistry, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.
Niyomura
Osamu
O
Nakaiida
Shohou
S
Kawahara
Yasuyuki
Y
Kanda
Takahiro
T
Yamada
Ryo
R
Hori
Shinya
S