The microwave spectrum, structure and nuclear quadrupole coupling constants for stibabenzene

Abstract

The microwave spectrum of 121-SbC5H5, 123-SbC5H5, [beta]-dideutero 121-SbC5H3D2 and 123-SbC5H3D2 has been assigned in the region 26.5-40.0 GHz. The respective rotational constants and uncertainties are: A = 4512.69 +/- 0.42, B = 1738.00 +/- 0.01, C = 1254.51 +/- 0.01; A = 4512.84 +/- 0.30, B = 1729.80 +/- 0.01, C = 1250.22 +/- 0.01; A = 4176.18 +/- 0.33, B = 1660.94 +/- 0.01, C = 1188.15 +/- 0.01; A = 4176.60 +/- 0.61, B = 1652.94 +/- 0.03, C = 1184.03 +/- 0.03 (in MHz units). The structure is found to be planar, C2v in symmetry. The d(Sb-C) = 2.050 +/- 0.005 A and [angle]CSbC = 92.9[deg] +/- 1.0[deg]. The nuclear quadrupole coupling constants for the 121 and 123 antimony isotopes are [chi]aa = 456.4 +/- 4.1 MHz, [eta] = 0.396 +/- 0.008, and [chi]aa = 583.00 +/- 5.3 MHz, [eta] = 0.399 +/- 0.008, respectively. Several alternate techniques using the coupling constants as data support a [sigma]-donating property for antimony.