Relative Stability and Structure of Dihydro-1,2,4-triazines: A Theoretical Study.

A brief survey is given on the synthesis and structure elucidation for dihydro-1,2,4-triazines. The relative stability of nine possible dihydro-1,2,4-triazines and three dihydrotriazinium cations is studied at HF, MP2, generalized gradient approximation DFT, and CBS-4 levels of theory. The structural consequences of the inclusion of the electron correlation are also given.