1,1′-Bis(4-fluorophenyl)-3,3′-diisobutyl-4,4′-diphenoxy-1H,1′H-4,4′-bipyrazole-5,5′(4H,4′H)-dione

In the title compound, C38H36F2N4O4, the pyrazole rings form dihedral angles of 50.02 (4) and 18.05 (4)° with their attached fluorobenzene rings, and make dihedral angles of 76.08 (4) and 73.54 (5)° with the aromatic ring of the attached phenoxy group. In the crystal, the molecules are connected by weak C—H⋯π interactions.

In the title compound, C 38 H 36 F 2 N 4 O 4 , the pyrazole rings form dihedral angles of 50.02 (4) and 18.05 (4) with their attached fluorobenzene rings, and make dihedral angles of 76.08 (4) and 73.54 (5) with the aromatic ring of the attached phenoxy group. In the crystal, the molecules are connected by weak C-HÁ Á Á interactions.

Related literature
For the synthesis and applications of pyrazole derivatives, see: Venkat Ragavan et al. (2009Ragavan et al. ( , 2010. For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986 Table 1 Hydrogen-bond geometry (Å , ).
Cg1 is the centroid of the N2 C8 double bond. Cg3 and Cg5 are the centroids of the C1-C6 and C19-C24 rings, respectively.

Comment
Antibacterial and antifungal activities of the azoles are most widely studied and some of them are in clinical practice as anti-microbial agents. However, the azole-resistant strains has led to the development of new antimicrobial compounds. In particular pyrazole derivatives are extensively studied and used as antimicrobial agents. Pyrazole is an important class of heterocyclic compound and many pyrazole derivatives are reported to have the broad spectrum of biological activities, such as anti-inflammatory, antifungal, herbicidal, anti-tumour, cytotoxic, molecular modelling, and antiviral activities. Pyrazole derivatives also act as antiangiogenic agents, A3 adenosine receptor antagonists, neuropeptide YY5 receptor antagonists, kinase inhibitor for treatment of type 2 diabetes, hyperlipidemia, obesity and thrombopiotinmimetics. Recently urea derivatives of pyrazoles have been reported as potent inhibitors of p38 kinase. Since the high electronegativity of halogens (particularly chlorine and fluorine) in the aromatic part of the drug molecules play an important role in enhancing their biological activity, we are interested to have 4-fluoro or 4-chloro substitution in the aryls of 1,5-diaryl pyrazoles. As part of our on-going research aiming the synthesis of new antimicrobial compounds, we have reported the synthesis of novel pyrazole derivatives and their microbial activities (Venkat Ragavan et al., 2009, 2010. In the molecule of the title compound ( Fig. 1), the pyrazole rings (N1-N2/C7-C9; N3-N4/C10-C12) form dihedral angles of 50.02 (4) and 18.05 (4)° with the attached benzene rings (C1-C6; C13-C18), and of 76.08 (4) and 73.54 (5)° with the aromatic ring of the attached phenoxy group (C19-C24; C25-C30). In the crystal structure (Fig. 2), there is no classical hydrogen bond and stabilization is provided by weak C-H···π interactions (Table 1), involving the centroids of the N2═C8 double bond (centroid Cg1), C1-C6 ring (centroid Cg3) and C19-C24 ring (centroid Cg5).

Refinement
All H atoms were positioned geometrically and refined using a riding model, with C-H = 0.93-0.97 Å and with with U iso (H) = 1.2 U eq (C) or 1.5 U eq (C) for methyl H atoms. A rotating group model was applied to the methyl groups. 4666 Friedel pairs were merged in the final refinement cycles.