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. Ph 2 P-NH-PPh 2 in the solid state is indeed a bis(diphenylphosphino)amin having C 2 molecular symmetry. Its bisborane(3) ad­duct possesses the structure Ph 2 P(BH 3 )-NH-P(BH 3 )Ph 2 with the BH 3 -groups in transoid position. The P-NH-P unit is also observed in (PhO) 2 P(O)-NH-P(O)(OPh) 2 and (PhO) 2 P(O)-NH-P(O)(C 2 H 5 ) 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 = BH 3 > S > O, e.g. with the electron withdrawing ability of X.