Conformational, structural analysis and vibrational spectra of a new carbacylamidophosphate compound: Experimental and theoretical study

N,N′-bis(pyrolidino), N″-trichloroacetyl phosphoric triamide, the new carbacyclamidophospate, was synthesized and its crystal structure has been determined by X-ray single crystal diffraction analysis. The crystal structure showed two independent conformers A and B. This compound produced dimmeric aggregate due to hydrogen bonding. The compound crystallizes in orthorhombic space group Pbca with a=12.033(2) Å; b=20.148(3) Å; c=24.876(3) Å; V=6030.7(13) (Å)3, Z=8; and D=1.538 mg/m3. The structure was solved by direct methods and refined to R=0.0657 and wR2=0.1415 by full matrix anisotropic least-squares methods. The molecular geometry and vibrational frequencies of the compound in the ground state have been calculated using the Hartree-Fock with HF/6-31+G* and HF/6-311++G** and density functional method (B3LYP) with B3LYP/6-31+G* and B3LYP/6-311++G** basis set. The optimized bond lengths and bond angles are show better agreement with the experimental values by RHF/6-311++G** method. The conformer A is approximately 6 kcal/mol more stable than conformer B. The energy profile was calculated for more stable structure, conformer A, by RHF/6-31+G* method as a function of θ° [O(1)-P(1)-N(3)-C(9)]. The harmonic vibrations computed of this compound by the RHF and DFT methods are in a good agreement with the observed IR spectral data.