Covalent three-dimensional titanium(IV)-aryloxide networks

Ti((OPr)-O-i)(4) was treated with 2.58 equiv of hydroquinone in THF to yield a red-orange powder formulated as [Ti(OC6H4O)(a)(OC6H4OH)(3.34-1.83a)((OPr)-Pr-i)(0.66-0.17a) (THF)(0.2)](n) (1, (0.91 less than or equal to a less than or equal to 1.82)) based upon D2O/DCl quenching studies. Treatment of 1 with an excess of hydroquinone in Et2O or DME afforded burgundy [Ti-2(mu(1,4)-OC6H4O)(2)- (mu(1,4)-OC6H4OH)(2)(mu-OC6H4OH)(2)](infinity) (2). Burgundy [Ti-2(mu(1,4)-OC6H4O)2(mu(1,4):eta(2),eta(1)-OC6H4O)(2)(OH2)(2) . (H2O)(2) . (H-OC6H4OH) . (MeCN)](infinity) (4) was prepared from 1 and excess wet hydroquinone in CH3CN. The acetonitrile in 4 can be exchanged for THF or DME. Treatment of Ti((OPr)-Pr-i)(4) with similar to 4 equiv of 2,7-dihydroxynaphthalene in Et2O at 100 degrees C (2 days) in a sealed tube yielded orange crystals of [Ti-2(mu(1,7)-OC10H6O)(2)(eta(1,7):eta(2),eta(1)-OC10H6OH)(2)((OPr)-Pr-i)(2)](infinity) (5). Diffraction studies were conducted at the Cornell High Energy Synchrotron Source (CHESS) because of the small crystal sizes. 2 (C18H14O6Ti, monoclinic, P2(1)/n, a = 9.624 (2), b = 11.283 (2), c = 14.916 (3), beta = 90.47(3)degrees, Z = 4), 4 (C32H33NO14Ti2, monoclinic, P2(1)/n, a = 16.137 (3), b = 10.762 (2), c = 20.368 (4), beta = 111.65(3)degrees, Z = 4), and 5 (C23H20O5Ti, orthorhombic, Pbca, a = 11.095 (2), b = 17.970 (4), c = 19.484 (4), Z = 8) are 3-dimensional materials based on diaryloxide connectivity between geometrically similar edge shared (i.e., Ti-2(mu-OAr)(2)) bioctahedral dititanium building blocks. While 2 and 5 possess a roughly body-centered arrangement of dititanium units, 4 has a hexagonal secondary structural motif. The nature of crystallization through alcoholysis is also discussed.