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The crystal structure of the heterocyclic compound 2-(4-methoxyphenyl)-7-phenylpyrazolo[1,5-c]pyrimidine, C19H15N3O, has been determined and its self-assembly on the surface of graphite has been examined using atomic force microscopy (AFM). The title compound crystallized in the monoclinic space group P21/c, with two independent molecules in the asymmetric unit. The packing of the L-shaped molecules in the crystal is governed by arene interactions, in the absence of any conventional hydrogen-bonding interactions. The packing arrangement reveals four types of dimeric motifs stabilized by π–π and C—H...π interactions. At low coverage, molecules assemble into long needle-like islands on the graphite surface. High-resolution AFM images reveal that the molecules interact through weak noncovalent interactions between the aromatic H atoms and the methoxy O atoms.

The crystal structure of methyl-I 6, nor-5-hydroxy-6,7,15-trioxo dehydroabietate has been determined from three-dimensional X-ray diffraction data. The compound crystallizes in the orthorhombic space group P2,2,2 with unit cell parameters a = 19.226(3) 8,, b = 11.075(3) A, c = 8.375(2) A, Z = 4, V = 1783.3(7) A3, do = 1.36 g~m -~. The gross structure was determined by direct methods which on refinement yielded a final value of R index as 0.038. Ring A is a chair, ring B an envelope whereas the ring C adopts a strictly planar conformation. The rings A and B are trans fused. The ester group at C 4 is cis fused to methyl carbon C15 whereas another methyl carbon C18 and 0x0 O(15) of the isopropyl group at C13 are rotated to positions 0.!07(3) 8, and 0.179(2) A out of the plane of ring C.