**3.3 Structural analysis of 2-(4-fluorophenyl)-4,5-dimethyl-1-(4-methylphenyl)- 1***H***-imidazole (FPDMMPI)**

The FPDMMPI's detailed structure is illustrated in this section [12]. The structure was solved by SHELXS97 [19]. The final crystal structure model is enhanced using the tool SHELXL97 [19].

This compound belongs to the monoclinic crystal system with the space group P21/ n. Molecular formula: C18H17N2; molecular weight: 280.34; crystal data: a = 9.8888 (2) Å; b = 7.6693 (1) Å; c = 20.1017 (5) Å; β = 95.915 (1)°; V = 1516.40 (4) Å3 ; Z = 4;

*Selected Imidazole Derivatives: Synthesis and X-Ray Crystal Structure – A Review DOI: http://dx.doi.org/10.5772/intechopen.108488*

#### **Figure 4.** *The thermal displacement ellipsoid plot [20] is shown at a 30% probability level.*

Dx = 1.228 Mg m<sup>3</sup> ; F(000) = 592; final R[F<sup>2</sup> > 2σ(F<sup>2</sup> )] = 0.049 and wR(F<sup>2</sup> ) = 0.153 for 2617 reflections observed with I > 2σ(I).

With CdH = 0.93–0.96 Å; Uiso(H) = kUeq(C), where k = 1.5 for dCH3 and 1.2 for the other H atoms, all the hydrogen atoms were geometrically arranged and admitted to riding on their parent atoms.

In this molecule (**Figure 6**), the dihedral angles made by (C11dC16) and (C21dC26) rings are 72.33 (8)° and 18.71 (8)° with the planar imidazole ring. Benzene rings makes a 75.05 (7)° dihedral angle. The C12dH12⋯N3 (2 x, 1 y, z) and C16dH16⋯N3 (2 x, 2 y, z) intermolecular hydrogen bonds stabilize the crystal (**Figure 7**).

The ORTEP-3 for Windows drew the thermal displacement ellipsoid plot with a 30% probability level [20] (**Figure 6**). The crystal packing using the PLATON [21] was viewed along the a-axis (**Figure 7**).
