Polymorphic di-2-pyridyl ketone 4-nitrophenylhydrazone (dpknph) : the structure of β-dpknph

A new polymorph of di-2-pyridyl ketone 4-nitrophenylhydrazone [alternative name: N-(dipyridin-2-ylmethylene)-N'-(4-nitrophenyl)hydrazine], C17H13N5O2, isolated from the filtrate of a sonicated acetonitrile solution of dpknph and CdCl2, was found to crystallize in the monoclinic space group P21/c, in contrast to the known form which crystallizes in P21/n. The non-coplanar molecules pack in parallel stacks without any intermolecular hydrogen-bonding interactions. This packing pattern contrasts with the interlocked interdigitated packing seen in the previously known polymorph.