Synthesis, spectroscopic study, X-ray crystallography and ab initio calculations of the two new phosphoramidates: C6H5OP(O)(NHC6H11)2 and [N(CH3)(C6H11)]P(O)(2-C5H4N-NH)2

Two new phosphoramidates with formula C6H5OP(O)(NHC6H11)2 (1) and [N(CH3)(C6H11)]P(O)(2-C5H4N-NH)2 (2) were synthesized and characterized by 1H, 13C, 31P NMR and IR spectroscopies and elemental analyses. The crystal structures of these compounds were determined using X-ray crystallography. Compound 1 [triclinic, P1¯, a = 8.8679(16) Å, b = 10.230(2) Å, c = 12.511(2) Å, α = 95.918(4)°, β = 103.948(4)°, γ = 110.818(4)°, Z = 2] forms a centrosymmetric dimmer via two equal intermolecular PO⋯HN hydrogen bonds. In this structure, intermolecular hydrogen bonds are also formed between the crystallization solvent and phosphoramidate molecules. Compound 2 [monoclinic, P21/c, a = 11.4760(7) Å, b = 18.5607(12) Å, c = 8.6227(6) Å, β = 108.751(5)°, Z = 4] produces a one-dimensional polymeric chain through intermolecular PO⋯HN hydrogen bonds, and a weaker intramolecular N⋯HN hydrogen bond has been also observed in the crystal. Ab initio quantum chemical calculations were performed for molecules 1 and 2 by the density functional three-parameter hybrid (DFT/B3LYP) and the Hartree–Fock (HF) methods, using the 6-31G∗ basis set. The compound 1:CH3OH pair was also calculated as observed in the crystal. The computed geometrical parameters are in good agreement with the experimental results.