Syntheses and Crystal Structures of Two New Binary Cocrystals of 3-Methyl-4-nitro-pyridine-N-oxide with o-Nitrobenzoic Acid and 3,5-Dinitrosalicylic Acid

Two new binary cocrystals formulated as POM.NBA 1 and POM-DNSA 2(POM =3-methyl-4-nitro-pyridine-N-oxide,NBA = o-nitrobenzoic acid,DNSA = 3,5-dinitrosalicylic acid)have been successfully synthesized and characterized by elemental analysis,IR and X-ray singlecrystal diffraction analysis.The crystal of 1 crystallizes in triclinie,space group P-1,with a =7.621(4),b = 7.816(4),c = 11.702(5)(A),α= 87.957(10),β = 83.642(10),γ,= 81.535(10)°,C13H11N3O7,Z = 2,Mr = 321.25,V= 685.1(6)(A)3,Dc = 1.557 g/cm3,F(000)= 332,μ= 0.129 mm-1,the final R = 0.0632 and wR = 0.0831.The crystal of 2 crystallizes in monoclinic,space group P21/c with a = 14.910(9),b = 5.904(3),c =19.321(12)(A),β = 110.583(10)°,C13H10N4O10,Z = 4,Mr =382.25,V= 1592.1(16)(A)3,Dc = 1.595 g/cm3,F(000)= 784,μ= 0.140 mm-1,the final R = 0.0598 and wR = 0.1589.Further structure analysis reveals that the POM with NBA and DNSA molecules in 1 and 2 are linked into 3D structures by the combination of strong O-H...O and weak C-H...O hydrogen bonds,π...π stackings and diverse short contacts,in which different C-H...O weak hydrogen bonds may play a key role in constructing the network structures.