Nitrogen Quadrupole Coupling Constants in Ethyl Cyanide; Coupling Constant of the Cyano Group

摘要

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:khgr;aathinsp;equals;thinsp;minus;thinsp;3.309thinsp;plusmn;thinsp;0.033,khgr;bbthinsp;equals;thinsp;1.265thinsp;plusmn;thinsp;0.013, andkhgr;ccthinsp;equals;thinsp;2.044thinsp;plusmn;thinsp;0.020MHz. These results indicate the existence of cylindrical symmetry about the CN bond with a quadrupole coupling constant along the bond axis ofkhgr;CNthinsp;equals;thinsp;minus;thinsp;4.14thinsp;plusmn;thinsp;0.04MHz. The coupling constants in ethyl cyanide and several other cyano compounds have been described by an extended Huuml;ckel scheme.