DOI: 10.1007/s00214-022-02936-z  (OpenAccess)

A theoretical study of dynamic processes observed in trimethylsilyl-1H-pyrazoles: prototropy and silylotropy

The ¹H, ¹³C, ¹⁵N and ²⁹Si chemical shifts of three trimethylsilyl-1H-pyrazoles were calculated and compared with literature results; the calculations were carried out at the GIAO/B3LYP/6–311++G(d,p) level resulting in a very good agreement that allows to predict with confidence the missing experimental values. The prototropic barrier of 4-trimethylsilyl-1H-pyrazole (1) as well as the silylotropic barriers of 1-trimethylsilyl-1H-pyrazole (2) and 1-trimethylsilyl-4-methyl-1H-pyrazole (3) were also calculated and the mechanism was established, the accordance with the experimental values being satisfactory.