CYCLIC-3-COORDINATE, CYCLIC-4-COORDINATE, CYCLIC-5-COORDINATE, AND CYCLIC-6-COORDINATE NITROGEN-CONTAINING PHOSPHORUS-COMPOUNDS VARYING IN RING SIZE FROM 5-MEMBERED TO 10-MEMBERED - P-N DONOR ACTION

New nitrogen-containing phosphorus compounds 1 and 3-5 were prepared b y the reaction of a nitrogen-containing phenol with PhPCl2. Hydrolysis of 1 gave an acyclic anionic phosphinate hydrogen bonded to an ammoni um component (2). Use of a nitrogen-containing diol with P(OPh)(3) res ulted in oxidative addition to give hexacoordinate pentaoxyphosphorus compound 6 exhibiting P-N donor action. X-ray analyses performed on al l six phosphorus compounds revealed a variety of geometries extending from three- to six-coordinate with ring sizes varying from five- to te n-membered. The structure of 3 is displaced toward a trigonal bipyrami d (TBP) as a result of weak P-N donor action. As a consequence of N-C bond cleavage, 1 forms as a bicyclic phosphorane with the nitrogen ato m located at an equatorial site of a TBP. In the formation of the tetr acoordinate cyclic phosphinate 5, a P-C bond is formed at the expense of O-C bond cleavage of the reactant diol. H-1 and P-31 NMR spectra in dicated that the basic coordination structures were retained in soluti on. It is concluded that the more elusive donor action found for nitro gen relative to sulfur and oxygen is a consequence of bond cleavage re actions. However, with sufficient phosphorus electrophilicity in highe r valent states, P-N donor action is achievable as found in the pentao xyphosphorane (6) in this study while more modest donor action takes p lace in the lower coordinate state present in 3.