Synthesis, crystal structure and computational studies of 4-nitrobenzylphosphonic acid

•4-Nitrobenzylphosphonic acid (1a) has been synthesized and characterized.•1a Displays a layered structure with weak CH⋯O(N) hydrogen bonds between layers.•The layer is composed of R42(12) and R44(16) ring motifs, exhibiting large stabilization energies.•The cohesive energy of 1a is much more advantageous than that of its carboxylic analogue.

4-Nitrobenzylphosphonic acid (1a) has been synthesized and structurally characterized by vibrational spectroscopy (IR and Raman) and single-crystal X-ray diffraction. Additionally, Hirshfeld surface analysis and computational methods have been used to compare the intermolecular interactions in the crystal structures of 1a and its carboxylic analogue, 4-nitrobenzylcarboxylic acid (4-NBCA). The crystal structure analysis of 1a has revealed that the acid molecules are extended into helical chains along the b axis using one of the hydrogen bonds established between phosphonic groups. The second (P)OH⋯O(P) hydrogen bond cross-links the inversion-related chains to form a thick monolayer with phosphonic groups arranged inwards and aromatic rings outwards. The nitro groups serve to link the neighbouring monolayers by weak CH⋯O(N) hydrogen bonds. Computations have confirmed the great contribution of electrostatic interactions for the crystal lattice stability. The cohesive energy, computed for the crystal structure of 1a exceeds 200 kJ mol−1 in magnitude and is nearly twice as large as that of 4-NBCA. The calculated cohesive energy values have been further related to the results of thermal analyses.

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