화학공학소재연구정보센터
Inorganic Chemistry, Vol.38, No.3, 519-530, 1999
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-ClC6H4COTeCH3), whose crystals are monoclinic (P2(1)/a) with a = 5.975(3) Angstrom, b = 14.517(2) Angstrom, c = 10.617(3) Angstrom, beta = 92.74(3)degrees, V = 919.8(4) Angstrom(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) Angstrom, respectively, indicating C=O double and C-Te single bonds. The C-Te-C angle of the C(O)TeCH3 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 v(C=O) bands and the C-13=O and Te-125 NMR spectra of the sodium and potassium tellurocarboxylates are discussed in comparison with those of other alkali metal or oxygen, sulfur, and selenium isologues.