Syntheses, crystal structure and ab initio calculations of two new phosphoric triamides

The reaction of N-benzoylphosphoramidic dichloride with piperidine and 4-methylpiperidine lead to PhC(O)N(H)P(O)R2 with RZpiperidine (1) and RZ4-methylpiperidine (2) as N-benzoyl-N0,N00-bis(piperidine) phosphoric triamide and N-benzoyl-N0,N00-bis(4-methylpiperidine) phosphoric triamide, respectively. The products have been characterized by 1H, 13C, 31P NMR spectra, and by elemental analysis. The crystalline solid for (1) and (2) consists surprisingly of four and two independent molecules, respectively. There is a disorder in one amine group due to ring inversion in each conformer in compound 1. In the solid state, comparablemagnitudes for the stabilization of the stable conformers for the more or less discrete molecules, the polarization effects, hydrogen bonding and the packing effects could be anticipated. The geometry of compound (1) optimized by density functional calculations at the B3LYP/6-31CCG* (d,p) level, is in good agreement with data obtained from X-ray crystallography. q 2005 Elsevier B.V. All rights reserved.