THE CHEMISTRY AND STRUCTURE OF THEP(O)NC(O) SYSTEM. PART 2. CRYSTAL ANDMOLECULAR STRUCTURE OF N-DIETHOXYPHOSPHORYLFORMAMIDINE

Abstract

The crystal and molecular structure of N-diethoxyphosphorylformamidine (2) has been determined. P2₁/n, a = 8.343(1), b = 9.249(1), c = 12.413(1) Å β = 102.06 (1)°; V = 937(1) Å.³ Final R_w = 0.052 for 1705 reflections with I > 3σ(I) and 113 parameters. Molecular parameters indicate strong electron-donating effect of the amidine substituent, resulting in high P[sbnd]N bond order and small difference between the two C[sbnd]N bond distances. The geometry of the molecule is different from that observed for phosphoric-carboxylicimides: the O[dbnd]P[sbnd]N[dbnd]C[sbnd]NH₂ system is almost planar with the phosphoryl oxygen in short contact with the sp² carbon atom.

Key Words:

• N-phosphorylated formamidine
• Crystal and molecular structure
• P[sbnd]N bond distance
• O[dbnd]P[sbnd]N bond angle
• Geometry of the O[dbnd]P[sbnd]N[sbnd]C[sbnd]X skeleton
• electrophilicity/nucleophilicity of the P(O)NC(O) system.