부산대학교 도서관

The spirocyclic (chloro)tetraoxyphosphorane CH2(6-t-Bu-4-Me-C6H2O)2P(Cl)(1,2-O2C6Cl4) (2) and its hydrolysis product CH2(6-t-Bu-4-Me-C6H2O)2P(O)(OC6Cl4-2-OH) (3) have been synthesized and characterized by X-ray crystallography and solution state NMR. Unlike the previously reported spirocyclic chlorophosphoranes where chlorine occupies an equatorial position of a trigonal bipyramid (TBP), in 2 it is apical. The hydrolysis product 3 is a hydrogen bonded dimer. Compound CH2(6-t-Bu-4-Me-C6H2O)2P(Cl)[1,2-O2–3,5-(t-Bu)2C6H2] (4) was also synthesized in a manner analogous to that of 2. Attempts to isolate structurally characterizable pentacoordinate compounds by reacting CH2(6-t-Bu-4-Me-C6H2O)2PX [X=Cl (1), 2,6-Cl2C6H3O (5), cycl-C6H11NH (6)] with N-chlorodiisopropylamine were not successful, although in some cases a pentacoordinate species was detected; the corresponding oxidized products CH2(6-t-Bu-4-Me-C6H2O)2P(O)X [X=Cl (7), 2,6-Cl2C6H3O (8), cycl-C6H11NH (9)] were isolated by this route. Variable temperature (1H, 31P) NMR spectra of 2 have been recorded; at low temperatures, two 31P NMR signals of unequal intensity are seen in the pentacoordinate region. A probable intramolecular process involving equatorial–equatorial↔apical–equatorial (for the eight-membered ring) has been invoked to explain the spectral features. [Copyright &y& Elsevier]