Crystal and Molecular Structures of Three Organic Salts from Nevirapine

Abstract

The preparation, X-ray crystal structure, Fourier Transform infrared (FTIR) spectroscopy, and elemental analysis of three compounds of the non-nucleoside reverse transcriptase inhibitor nevirapine are reported. XRD and FTIR analysis indicated that all these complexes are organic salt. The compound 1 crystallizes in the triclinic, space group P−1, with a = 9.147(1) A, b = 9.494(2) A, c = 11.948(2) A, α = 111.079(2)°, β = 90.0890(10)°, γ = 95.0780(10)°,V = 963.7(3) A3, Z = 2. The compound 2 crystallizes in the monoclinic, space group C2/c, with a = 21.608(2) A, b = 12.860(1) A, c = 15.653(1) A, β = 92.2940(10)°, V = 4346.1(6) A3, Z = 8. The compound 3 crystallizes in the monoclinic, space group P2(1)/c, with a = 9.013(1) A, b = 26.580(2) A, c = 8.360(1) A, β = 114.789(2)°, V = 1818.3(3) A3, Z = 4. Nevirapine molecules are linked essentially by the N–H···O hydrogen bonds, forming centrosymmetric dimers. In the dimers every nevirapine displays a butterfly-like conformation with the cyclopropyl group directed towards the concave face of the molecule. In this work, the hydrogen bonding interactions in the salts have been investigated. The role of weak and strong hydrogen bonding in the crystal packing is ascertained. In the three prepared salts there are plenty of weak nonbonding interactions such as directional hydrogen bonds of N–H···O (neutral and ionic), intra- and interchain CH–N, CHn···O (n = 1, 2, 3), CH-S, O-C contact, O-π, CHn-π (n = 1 and 2), and π-π interactions. Due to these collective weak interactions, all the compounds displayed 3D framework structures.