Crystal structure of 3,4-dihydroxy-1,5-dimethyl-2-phenylpyrazolium chloride, [C11H13N2O2]Cl

C11H13ClN2O2 ,t riclinic, P1 (no. 2), a =7 .150(5) A, b =8 .380(2) A, c =1 0.586(2) A, + =7 1.80(2)°, * =8 4.05(5)°, & =8 7.47(5)°, V =5 99.3 A 3 , Z =2 , Rgt(F) =0 .049, wRref(F 2 ) =0 .176, T =2 93 K. Source of material The title compound was obtained by dissolving 4-hydroxyantipyrine (0.408 g, 0.002 mole) in acetonitrile (10 ml) and then adding carefully of titanium tetrachloride (0.39 g, 0.002 mole) under nitrogen. Aw eek later white crystals appear from the acetonitrile solution. TiCl4 catalyzes the reaction. As uitable crystal was taken for X-ray diffraction studies. Experimental details The two Ha toms involved in hydrogen bonding (H1 and H2) were first located from ad ifference Fourier map and then refined isotropically. Other Ha toms were positioned geometrically and treated as riding on their parent atoms with d(C—H) =0 .96 A (CH3 )a nd Uiso(H) =1 .5 Ueq(C) or d(C—H) =0 .93 A (aromatic) and Uiso(H) =1 .2 Ueq(C). The attempts at recrystallization of the compound did not improve crystals quality, which explains the relatively large residual values. Discussion