**3.6 Structural analysis of 2-(4-fluorophenyl)-1-(4-methoxyphenyl)-4,5 dimethyl-1***H***-imidazole (FPMOPDMI)**

This section depicts the structure details of FPMOPDMI [15]. SHELXS97 [19] solved the crystal structure. The program SHELXL97 [19] refines the final crystal structure model.

This compound belongs to the monoclinic crystal system with the space group P21/ c. Molecular formula: C18H17FN2O; molecular weight: 296.34; crystal data: a = 8.5132 (1) Å; b = 9.5128 (2) Å; c = 19.2610 (3) Å and β = 96.798 (2)°; V = 1548.87 (4) Å3 ; Z = 4; Dx = 1.271 Mg m<sup>3</sup> ; F(000) = 624; final R[F<sup>2</sup> > 2σ(F<sup>2</sup> )] = 0.041 and wR (F<sup>2</sup> ) = 0.130 for 2744 reflections observed with I > 2σ(I).

With CdH = 0.93 Å for Csp2 and 0.96 Å for Csp<sup>3</sup> , and Uiso(H) = kUeq(C), where k = 1.5 for dCH3 and 1.2 for the other H atoms, all the hydrogen atoms were guided geometrically and admitted to riding on their parent atoms.

In this molecule (**Figure 11**), with a maximum deviation of 0.005 (1) Å for C2, the imidazole ring is planar. The imidazole ring makes dihedral angles of 76.46 (7)° and 40.68 (7)° with the (C11dC16) and (C21dC26) rings, respectively. 71.25 (6)° is the dihedral angle among benzene rings. No classical hydrogen bonds are found in the crystal.

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

The ORTEP-3 for Windows drew the thermal displacement ellipsoid plot with a 30% probability level (**Figure 11**) [20].
