A theoretical and experimental study on the Lewis acid-base adducts (P4E3)center dot(BX3) (E = S, Se; X = Br, I) and (P4Se3)center dot(NbCl5)

The Lewis acid-base adducts (P4E3). (BX3) (E = S, Se; X = Br, I) and (P4Se3 ). (NbCl5) have been prepared and characterized by Raman, IR, and solid-sta te P-31 MAS NMR spectroscopy. Hybrid density functional calculations (B3LYP ) have been carried out for both the apical and the basal (P4E3). (BX3) (E = S, Se; X = Br, I) adducts. The thermodynamics of all considered species h as been discussed. In accordance with solid-state P-31 MAS NMR and vibratio nal data, the X-ray powder diffraction structures Of (P4S3). (BBr3) [monocl inic, space group P2(1)/m (No. 11), a = 8.8854(l) Angstrom, b = 10.6164(2) Angstrom, c = 6.3682(l) Angstrom, beta = 108.912(1)degrees, V = 568.29(2) A ngstrom (3), Z = 2] and (P4S3). (BI3) [orthorhombic, space group Pnma (No. 62), a = 12. 5039(5) Angstrom, b = 11.3388(5) Angstrom, c = 8.9298(4) Angst rom, V = 1266.09(9) Angstrom (3), Z = 4] indicate the formation of an apica l P4S3 Complex in the reaction Of P4S3 with BX3 (X = Br, I). Basal adducts are formed when P4Se3 is used as the donor species. Vibrational assignment for the normal modes of these adducts has been made on the basis of compari son between theoretically obtained and experimentally observed vibrational data.