POLYMORPHISM AND CO-CRYSTALS:A CASE STUDY OF AMINO-NITROPYRIDINES. By M.Nieuwenhuyzen and C.B.Aakeroy.
The crystal structures of four compounds from a family of commonly used building blocks for non-linear optical materials, amino-nitropyridines, have been determined, 2-amino-5-nitropyridine1 1,the solvated compound 2-amino-5-nitropyridine monohydrate1 2, a new polymorph of 2-amino-3-nitropyridine1 3, and the co-crystal 2-amino3-nitropyridine with 2-amino-5-nitropyrimidine2 4. These compounds are all stabilised by a combination of hydrogen bonds (including C--H .... X interactions) and ring-ring interactions. The balance between these intermolecular forces and the way they influence the packing of these materials is examined, and the problems associated with polymorphism in this system is addressed.
References:
1) C.B.Aakeroy, M.Nieuwenhuyzen, A structural study of 2-amino-5-nitropyridine and 2-amino-5-mtropyridine; Molecular building blocks for non-linear optical materials., submitted to J. Mat. chem..
2) C.B.Aakeroy, M.Nieuwenhuyzen, Manuscript n preparation.