Röntgenstrukturuntersuchungen an Verbindungen mit P—NH—P-Gerüst / X-Ray Structural Studies on Compounds with a P —NH-P Backbone

Abstract

Abstract The structures of four compounds containing the P-NH-P unit have been determined by X-ray methods in order to detect prototropism. Ph2P-NH-PPh2 in the solid state is indeed a bis(diphenylphosphino)amin having C2 molecular symmetry. Its bisborane(3) ad­duct possesses the structure Ph2P(BH3)-NH-P(BH3)Ph2 with the BH3 -groups in transoid position. The P-NH-P unit is also observed in (PhO)2P(O)-NH-P(O)(OPh)2 and (PhO)2P(O)-NH-P(O)(C2H5)2. These two compounds show weak intermolecular hydrogen bonding in the solid state to the oxygen atom of a phosphoryl group. The PN bond distances depend on the group X bonded to phosphorus and decrease in the series with X = BH3 > S > O, e.g. with the electron withdrawing ability of X.