Covalent Three-Dimensional Titanium(IV)−Aryloxide Networks

Ti((i)OPr)(4) was treated with 2.58 equiv of hydroquinone in THF to yield a red-orange powder formulated as [Ti(OC(6)H(4)O)(a)()(OC(6)H(4)OH)(3.34)(-)(1.83)(a)()(O(i)Pr)(0.66)(-)(0.17)(a)() (THF)(0.2)](n)() (1, (0.91 </= a </= 1.82)) based upon D(2)O/DCl quenching studies. Treatment of 1 with an excess of hydroquinone in Et(2)O or DME afforded burgundy [Ti(2)((1,4)-OC(6)H(4)O)(2)((1,4)-OC(6)H(4)OH)(2)(-OC(6)H(4)OH)(2)](infinity) (2). Burgundy [Ti(2)((1,4)-OC(6)H(4)O)(2)((1,4):eta(2),eta(1)-OC(6)H(4)O)(2)(OH(2))(2).(H(2)O)(2).(H-OC(6)H(4)OH).(MeCN)](infinity) (4) was prepared from 1 and excess wet hydroquinone in CH(3)CN. The acetonitrile in 4 can be exchanged for THF or DME. Treatment of Ti(O(i)Pr)(4) with approximately 4 equiv of 2,7-dihydroxynaphthalene in Et(2)O at 100 degrees C (2 days) in a sealed tube yielded orange crystals of [Ti(2)((1,7)-OC(10)H(6)O)(2)((1,7):eta(2),eta(1)-OC(10)H(6)OH)(2)(O(i)Pr)(2)](infinity) (5). Diffraction studies were conducted at the Cornell High Energy Synchrotron Source (CHESS) because of the small crystal sizes. 2 (C(18)H(14)O(6)Ti, monoclinic, P2(1)/n, a = 9.624 (2), b = 11.283 (2), c = 14.916 (3), beta = 90.47(3) degrees, Z = 4), 4 (C(32)H(33)NO(14)Ti(2), 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 (C(23)H(20)O(5)Ti, 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)(-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.