Beiträge zur Chemie des Bors, 208 Reaktionen eines Amino‐imino‐borans mit Phosphin‐, Phosphon‐ und Phosphorsäuren

Reactions of an Amino Imino Borane with Phosphinic, Phosphonic, and Phosphoric Acids Controlled 1:1 reactions of R 2 P(O)OH with tmp – B = NtBu ( 1 ) (tmp = 2,2,6,6‐tetramethylpiperidino group) in hexane leads to R 2 P(O)OB(tmp)NHtBu ( 2 ). In most other cases mixtures of 2 with other products are obtained. Application of a 4:1 ratio of Me 2 P(O)OH and 1 results in the formation of pure [tBuNH 3 ][B(OP(O)Me 2 ) 4 ] ( 3 ). Reaction of phosphonic acids with 1 in hexane at about –30°C leads preferentially to the addition of the acid to produce RP(O)[OB(tmp)NHtBu] 2 ( 4 ), while H 3 PO 4 reacts with 1 to yield OP[OB(tmp)NHtBu] 3 ( 6 ). Species containing tetracoordinated boron atoms are formed as well in dichloromethane as a solvent. Spectral data for the compounds 2 , 4 , and 6 reveal three‐coordinate boron atoms, confirmed by an X‐ray structure analysis of 2a (R = CH 3 ). This compound displays a fairly large B – O – P bond angle, 140.6(3)°.