PREPARATIONS AND X-RAY STRUCTURES OF COMPOUNDS CONTAINING THE 4-MEMBERED PN2TE RING

The reaction of Li[Ph(2)P(NSiMe(3))(2)] with TeCl4 in a 1:1 molar ratio in CH2Cl2 at -78 degrees C, followed by warming to 23 degrees C, produces Ph(2)P(NSiMe(3))(2)TeCl3 (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) Angstrom. When the same reaction is carried out in a 2:1 molar ratio, the product is Ph(2)P(NSiMe(3))(2)Te(Cl)NPPh(2)NSiMe(3) (2), which consists of a PN2Te ring with Te-N bond distances of 2.108(3) and 2.275(4) Angstrom and a short exocyclic tellurium-nitrogen bond of 1.922(4) Angstrom. Crystals of 1 are monoclinic, of space group P2(1)/n, with a = 15.494(7) Angstrom, b = 11.580(9) Angstrom, c = 15.823, beta = 96.46(3)degrees, V = 2820(2) Angstrom(3), and Z = 4. The final R and R(w) values were 0.024 and 0.027, respectively. Crystals of 2 are triclinic, of space group P $($) over bar$$ 1, with a = 12.372(7) Angstrom, b = 17.040(6) Angstrom, c = 11.648(4) Angstrom, alpha = 108.11(2)degrees, beta = 109.32(4), gamma = 88.76(4)degrees, V = 2193(2) Angstrom(3), and Z = 2. The final R and R(w) values were 0.036 and 0.037, respectively.