DI-TERT-BUTYL PHOSPHATE COMPLEXES OF TITANIUM

Reactions of 1 equiv of HO(O)P((OBu)-Bu-t)(2) with Ti(OR)(4) (R = Et, Pr-i) give the new molecular titanium phosphates [Ti(OR)(3)O2P((OBu)-B u-t)(2)](n) (1, R = Et; 2, R = Pr-i). In the solid state, 2 exists as a centrosymmetric dimer containing five-coordinate metal centers. Addi tion of 2 equiv of KOEt to an ethanol solution of 1 led to the formati on of [Ti2K(OEt)(8)O2P((OBu)-Bu-t)(2)](2) (3) and 1 equiv of KO2P((OBu )-Bu-t)(2). A single-crystal X-ray structure analysis of 3 revealed th at this complex exists in the solid state as a centrosymmetric dimer c ontaining two Ti-centered, face-sharing pseudooctahedra in the unique half of the dimer. Addition of 2 equiv of (KOPr)-Pr-i to a 2-propanol solution of 2 led to the formation of KO2P((OBu)-Bu-t)(2) (4) and Ti(( OPr)-Pr-i)(4) in high yield. Cooling a 2-propanol solution of 4 to -80 degrees C led to crystallization of the solvated tetramer [4 . (HOPr3 )-Pr-i](4) (mp = -30 degrees C). A single-crystal X-ray structure anal ysis revealed that this tetramer possesses a cubelike K4O4 core with 4 -fold improper rotation symmetry. Multinuclear NMR studies of 1-3 show that the structures of these complexes are dynamic in solution. Cryst als of 4 are tetragonal (P4(2)/(n)) with a = 15.6261(3) Angstrom, c = 14.7114(3) Angstrom, and Z = 8.