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) angstrom; b = 20.148(3) angstrom; c = 24.876(3) angstrom; V= 6030.7(13) Z= 8; and D = 1.538 mg/m(3). The structure was solved by direct methods and refined to R=0.0657 and wR(2) = 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, conformerA, by RHF/6-31 +G* method as a function of theta degrees[O(1)-P(1)N(3)-C(9)]. The harmonic vibrations computed of this compound by the RHF and DFIF methods are in a good agreement with the observed IR spectral data. (c) 2006 Elsevier B.V. All rights reserved.