Synthesis, spectroscopic study, X-ray crystallography and ab initio calculations of the two new phosphoramidates:: C6HOP(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 H-1 C-13. P-31 NMR and IR spectroscopies and elemental analyses. The crystal structures of these compounds were determined using X-ray crystallography. Compound I [triclinic, P (1) over bar, a = 8.8679(16) angstrom, b = 10.230(2) angstrom, c = 12.511(2) angstrom, alpha = 95.918(4)degrees, beta = 103.948(4)degrees gamma = 110.818(4)degrees, Z = 2] forms a centrosymmetric dimmer via two equal intermolecular P=O center dot center dot center dot H-N hydrogen bonds. In this structure, intermolecular hydrogen bonds are also formed between the crystallization solvent and phosphoramidate molecules. Compound 2 [monoclinic, P2(1)/c, a = 11.4760(7) angstrom, b = 18.5607(12) angstrom, c = 8.6227(6) angstrom, beta = 108.751(5)degrees, Z = 4] produces a one-dimensional polymeric chain through intermolecular P=O center dot center dot center dot H-N hydrogen bonds, and a weaker intramolecular N center dot center dot center dot H-N hydrogen bond has been also observed in the crystal. Ab initio quantum chemical calculations were performed for molecules I 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. (c) 2007 Elsevier B.V. All rights reserved.