The influence of the nitro group on the solid-state structure of 4-nitropyrazoles: the cases of pyrazole, 3,5-dimethylpyrazole, 3,5-di-tert-butylpyrazole and 3,5-diphenylpyrazole. I. Static aspects (crystallography and thermodynamics)

Protonation and phase effects on the NMR chemical shifts of imidazoles and pyrazoles: experimental results and GIAO calculationsElectronic supplementary information (ESI) available: absolute and relative shieldings calculated at the B3LYP/6-311++G**//B3LYP/6-311++G** level for compounds V to XXI as well as pyrazole and 3,5-dimethylpyrazole dimers, trimers and tetramers (420 shieldings). See http://www.rsc.org/suppdata/nj/b2/b210251j/

“…These compounds are either commercial or have been described by us in previous publications. [40][41][42] By plotting the chemical shift of C-4 for pyrazoles 4, 17, 18 and 19 (Y variables) against those of pyrazole 3 itself, Fig. 2 is obtained.…”

Experimental standard molar enthalpies of formation of crystalline 3,5-dimethylpyrazole, 3,5-dimethyl-4-nitrosopyrazole, 1,3,5-trimethyl-4-nitrosopyrazole, and 3,5-dimethyl-1-phenyl-4-nitrosopyrazole

“…All the experimental results are reported for the first time, except the enthalpy of sublimation of 3,5-dimethylpyrazole (table 3) for which there is a previous result in the literature, (83.3 ± 0.2) kJ · mol −1 , (22) obtained from measurements of vapour pressures, at (23) 3,5-dimethylpyrazole, (102.3 ± 2.9) kJ · mol −1 , obtained in this work, N -methylpyrazole, (156.5 ± 2.1) kJ · mol −1 , (24) and N -phenylpyrazole, (291.4 ± 4.5) kJ · mol −1 , (25) we estimate the values of f H o m (Me 3 Pyr, g) = (79 ± 10) kJ · mol −1 and f H o m (Me 2 PhPyr, g) = (214 ± 10) kJ · mol −1 , where the uncertainties are increased to ±10 kJ · mol −1 . The observed f H o m (g) values for 4-nitrosopyrazole derivatives and pyrazole derivatives are listed, as well as the increment for each pair of compounds, in table 4.…”

Mixed crystals of pyrazoles and benzoic acids. Part 1. The molecular structure of 3,5-dimethylpyrazole–2,4,6-trimethylbeflzoic acid co-crystals

“…The geometrical characteristics describing the molecular and crystal structure of compound 4 are supplied in (6) 115.1 (7) 121.4 (7) -62.8 ( 10) Hydrogen interactions X-H * . Y N(1 1)-H (11) O( 22)…”