10-(4-Chlorophenyl)-7-methyl-5,6-di-hydrobenzo[h]pyrazolo[5,1-6]quinazoline and 2-(4-chlorophenyl)-5-methyl-6,7-dihydrobenzo[h]pyrazolo-[1,5-a]quinazoline: Isomeric molecules linked into hydrogen-bonded dimers or π-stacked chains

Abstract

The isomeric title compounds 10-(4-chlorophenyl)-7-methyl-5,6- dihydrobenzo[h]pyrazolo[5,1-b]quinazoline, (I), and 2-(4-chlorophenyl)-5-methyl- 6,7-dihydrobenzo[h]pyrazolo[1,5-a]-quinazoline, (II), both C21H 16ClN3, exhibit peripheral delocalization in the heteroaromatic portion of the fused ring system. The molecules of (I) are linked into centrosymmetric dimers by a single C-H⋯π(arene) hydrogen bond, and the molecules of (II), where Z′ = 2, are linked by π-π stacking interactions into chains in which the two types of molecules alternate.