A vibrational study of di-i-propoxyphosphoryl benzylisothiourea

The Fourier transform infrared and Raman spectra of di-i-propoxyphosphoryl benzylisothiourea (DPB) (1) in the solid state and in solutions of CCl4, CH Cl3, CHBr3, CH2Cl2, C2H4Cl2, C2H4Br2 and THF were studied. In the IR spectr a, the effects of different concentrations were also investigated. The beha vior of the v(NH), sigma(NH), delta(HNH), v(C=N) and v(P=O) normal modes su ggests the existence of a tautomerism between the phosphorylamine (I) and N -phosphorylimine (TI) structures: [GRAPHICS] The data show the presence of different delta(NH) and delta(HNH) bendings a nd v(C=N) normal modes in the solid state as a result of inter and intramol ecular hydrogen bonding, The experimental approximate frequencies assignmen ts were done for this compound, and were confirmed by a normal coordinate a nalysis carried out for several fragments of phosphorylamine and N-phosphor ylimine structures. (C) 2000 Elsevier Science B.V. All rights reserved.