STRUCTURAL STUDIES OF CURCUMINOIDS .8. CRYSTAL AND MOLECULAR-STRUCTURE OF 4-BENZYL-1,7-DIPHENYL-1,6-HEPTADIENE-3,5-DIONE

4-Benzyl-1,7-diphenyl-1,6-heptadiene-3,5-dione, (DPBZHDD) C26H22O2, M = 366.5, crystallizes in the monoclinic space group P2(1)/c (No. 14). The unit cell dimensions are: a = 5.888(3), b = 8.664(5), 40.110(18) angstrom, beta = 92.93(4)degrees and V = 2043.4(5) angstrom3. The calculated density is 1.19 g cm-3 and Z = 4. The X-ray data were collected at room temperature (T= 293 K) using Mo Kalpha radiation (lambda = 0.71069 angstrom); the intensities of 1003 unique reflections with I > 3.0sigma(I) were used in the refinement procedure. The structure was refined to a conventional R-factor of 0.040 (R(w) = 0.035) giving e.s.d. in bond lengths and angles not involving hydrogen atoms of about 0.01 angstrom and 0.7-degrees, respectively. The interactions between the aromatic moieties are discussed and a hydrogen bond of the type C(arom)-H---O is suggested.