NITROGEN QUADRUPOLE COUPLING CONSTANTS IN ETHYL CYANIDE - COUPLING CONSTANT OF CYANO GROUP

An investigation of the hyperfine structure of the microwave transitions of ethyl cyanide has led to the following values of the nitrogen quadrupole coupling constants: χaa= -3.309±0.033, χbb=1-265±0.013, and χcc=2.044±0.020 MHz. These results indicate the existence of cylindrical symmetry about the CN bond with a quadrupole coupling constant along the bond axis of χCN= -4.14±0.04 MHz. The coupling constants in ethyl cyanide and several other cyano compounds have been described by an extended Hückel scheme.