| 20131806 |
Yi XY, Lam TC, Williams ID, Leung WH: Hydrolysis of bis (p-nitrophenyl) phosphate by tetravalent metal complexes with Klaui's oxygen tripodal ligand. Inorg Chem. 2010 Mar 1;49(5):2232-8.
The treatment of HfCl (4) with NaL (OEt) (L (OEt)(-) = [(eta (5)-C (5) H (5)) Co{P (O)(OEt)(2)}(3)](-)) in nitric acid afforded L (OEt) Hf (NO (3))(3) (1). Hydrolysis of 1 in acetone/water (4:1, v/v) yielded the hydroxy-bridged dimer [(L (OEt))(2) Hf (2)(H (2) O)(4)(mu-OH)(2)][NO (3)](4) (2). The treatment of (NH (4))(2)[Ce (NO (3))(6)] with 2 equiv of NaL (OEt) in water afforded (L (OEt))(2) Ce (NO (3))(2) (3), whereas that with 1 equiv of NaL (OEt) in CH (2) Cl (2) gave L (OEt) Ce (NO (3))(3) (4). While 4 is stable in organic solvents such as acetone, it was converted completely to 3 in acetone/water. The treatment of 3 with bis (p-nitrophenyl) phosphate (BNPP) afforded (L (OEt))(2) Ce [eta (1)-OPO (OR)(2)](2) (5; R = p-NO (2) C (6) H (4)), whereas the reaction of 4 with NaPO (2)(OR)(2) yielded dinuclear [L (OEt) Ce (NO (3))(2){mu-O (2) P (OR)(2)}](2) [R = p-NO (2) C (6) H (4) (6), Ph (7)]. The addition of 3 in acetone to an aqueous solution of NaH (2) PO (4) yielded the cerium (IV) dihydrogen phosphate complex (L (OEt))(2) Ce (PO (4) H (2))(2) (8). Complexes 1-5 and 7 have been characterized by X-ray crystallography. The hydrolysis of BNPP with L (OEt) M (NO (3))(3) (M = Zr, Hf, Ce) in acetone/water has been studied by (1) H NMR spectroscopy. At 25 degrees C, with [Ce] = 20 [BNPP], in an acetone-d (6)/N-(2-hydroxyethyl) piperazine-N'-2-ethanesulfonic acid (4:1, v/v) buffer solution (50 mM) (4:1, v/v), the hydrolysis of BNPP with 4 was found to exhibit first-order kinetics with a rate constant of (1.1 +/- 0.1) x 10 (-3) s (-1). |
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