Crystal and Molecular Structure of Two Organic Salts from 3,5-Dimethylpyrazole and Organic Acids

Abstract

Two compounds (3,5-dimethylpyrazole): (4-nitro-phthalic acid) (1) [(HL)+·(Hnpa)−, Hnpa = 4-nitro-hydrogenphthalate], and (3,5-dimethylpyrazole): (naphthalene-1,5-disulfonic acid) (2) [(HL+)2·(nds2−), nds2− = 1,5-naphthalenedisulfonate] were obtained from self-assembly of the corresponding acids with the 3,5-dimethylpyrazole, and their structures were fully characterized. Both compounds are ionic, with proton transfer occurring to the N of the 3,5-dimethylpyrazole moiety. The two structures adopted hetero supramolecular synthons. Compound 1 crystallizes in the monoclinic, space group P2(1), with a = 7.843(3) A, b = 6.8506(12) A, c = 12.816(2) A, β = 92.0710(10)°, V = 688.1(3) A3, Z = 2. Compound 2 crystallizes in the triclinic, space group P-1, with a = 8.0883(13) A, b = 8.2960(15) A, c = 8.9223(14) A, α = 75.502(14)°, β = 89.975(13)°, γ = 80.197(14)°, V = 570.60(16) A3, Z = 1. Supramolecular architectures of the compounds 1–2 involve O–H···O/N–H···O/N–H···S hydrogen bonds as well as other noncovalent associations. The role of these noncovalent interactions in the crystal packing is analysed. Both salts displayed 3D framework structure for the synergistic effect of the various noncovalent interactions. The crystal structures of the 3,5-dimethylpyrazole salts with 4-nitro-phthalic acid, and naphthalene-1,5-disulfonic acid show extensive hydrogen bonding as well as C–H···O, CH3···O, and C···π interections, giving three-dimensional networks.