Substituent Effects in 3,3′ Bipyrazole Derivatives. X-ray Crystal Structures, Molecular Properties and DFT Analysis

The single crystal X-ray structure of new 1,1'-bis(2-nitrophenyl)-5,5'-diisopropyl-3,3'-bipyrazole, 1, is triclinic P (I) over bar, a = 7.7113(8), b = 12.3926(14), c = 12.9886(12) angstrom, alpha = 92.008(8), beta = 102.251(8), gamma = 99.655(9)degrees. The structural arrangement is compared to that of 5,5'-diisopropyl-3,3'-bipyrazole, 5, whose single crystal structure is found tetragonal 14(1)/a, a = b = 11.684(1), c = 19.158(1) angstrom. The comparison is also extended to the structures previously determined for 1,1'-bis(2-nitrophenyl)-5,5'-propyl-3,3'-bipyrazole, 2, 1,1'-bis(4-nitrophenyl)-5,5'-diisopropyl-3,3'-bipyrazole, 3, and 1,1'-bis(benzyl)-5,5'-diisopropyl-3,3'-bipyrazole, 4. Density Functional Theory (DFT) calculations are used to investigate the molecular geometries and to determine the global reactivity parameters. The geometry of isolated molecules and the molecular arrangements in the solid state are analyzed according to the nature of the groups connected to the bipyrazole core.

Automated summary

The study compared the crystal structures of different diisopropyl bipyrazoles, and used Density Functional Theory (DFT) calculations to investigate molecular geometries and global reactivity parameters.