V. N. Sergeev

Crystal and molecular structures of (O-Ge)-chelate 1-(dimethylchlorogermylmethyl)pyrrolidone-2 and 1-(dimethylchlorogermylmethyl)piperidone-2, and of (N-Ge)-chelate O-(dimethylchlorogermylmethyl)-δ-valerolactim and 2-(chlorodimethylgermylmethylthio)-pyrrolidine-1. Structural correlations between derivatives of four- and five-coordinated germanium

Abstract An X-ray study of (O-Ge)-chelate 1-(dimethylchlorogermylmethyl)pyrrolidone-2 ( 1 ), 1-(dimethylchlorogermylmethyl)piperidine-2 ( 2 ), (N-Ge)-chelate O -(dimethylchlorogermylmethyl)-δ-valerolactim ( 3 ), and 2-(chlorodimethylgermylmethylthio)pyrrolidine-1 ( 4 ) has been carried out ( R = 0.033, 0.062, 0.097 and 0.048 for 1241, 2351, 1242 and 1838 reflections, respectively). The Ge atom has a distorted trigonal-bipyramidal [3 + 2] coordination with the axial Cl and O atoms in 1 and 2 or Cl and N atoms in 3 and 4 . The axial distances are Ge-Cl 2.324(2), 2.354(2), 2.458(8) and 2.566(2) A, Ge ← O 2.311(4) and 2.194(2), Ge ← N 2.148(18) and 2.064(5) A in 1 – 4 respectively. Correlation between structural parameters of the compounds of five- and four-coordinated germanium have been considered.

Crystal and molecular structure of the (N-Si) chelate of 2-(chlorodimethylsilylmethylthio)-1-pyrroline

The X-ray diffraction structural study of the (N-Si)-chelate of 2-(chlorodimethyl-silylmethylthio)-1-pyrroline was carried out (R = 0.033 for 1894 reflections). The Si atom has a somewhat distorted trigonal bipyramidal coordination with the Cl and N atoms in axial positions. The Si-Cl and Si-N distances (2.423(1) and 1.945(1) Å) belong, respectively, to the longest and shortest known Si-Cl and Si-N distances in pentacoordinated silicon derivatives with an axial N-Si-Cl moiety.

Crystal and molecular structure of 1-(trimethylsilylmethyl)hexahydroazepine-2-thione and hexahydroazepine-2-thione

The title compounds were prepared and X-ray analysis was performed (R = 0.064 and 0.035 for 1309 and 1637 reflections, respectively). In the former the intramolecular S→Si coordination interactions are absent and the Si atom has undistorted tetrahedral coordination with an S...Si distance of 4.034 Å. Crystals of the latter are built of centrosymmetric dimeric H-complexes (S...H(N) 2.58 Å, the S...HN angle 168°).