Department of Chemistry, University of North Dakota, Grand Forks, North Dakota 58202-9024, USA.
Inorg Chem. 2010 Mar 1;49(5):2163-72. doi: 10.1021/ic9019537.
The utility of tri-tert-butoxystannate as a chelating tridentate ligand for group 4 metals was investigated. The highly Lewis acidic metals degraded the stannate ion in a series of tert-butoxide abstraction steps to produce a variety of group 4 tert-butoxides. A total of 1 equiv of NaSn(O(t)Bu)(3) reacted with cis-MCl(4)(THF)(2) [M = Zr (1), Hf (2)] in THF solutions to furnish the salts fac-{M(O(t)Bu)(3)(THF)(3)}, which are separated ion pairs featuring weakly coordinating trichlorostannate ions. Neutral complexes, namely, [M(O(t)Bu)(2)Cl(2)(THF)(2)] [M = Zr (3), Hf (4)], were isolated when 2/3 equiv of sodium stannate was used in these reactions. Titanium tetrachloride formed analogues neither of 1 and 2 nor of 3 and 4, but Ti(O(t)Bu)(3)Cl reacted with silver triflate to give [Ti(O(t)Bu)(2)(OTf)(2)(THF)(2)] (5). Anion exchange of triflate for trichlorostannate transformed 1 to the contact ion pair fac-[Zr(O(t)Bu)(3)OTf(THF)(2)] (6). A total of 2 equiv of NaSn(O(t)Bu)(3) reacted with cis-MCl(4)(THF)(2) to give the complexes fac-[Sn(mu-O(t)Bu)(3)M(O(t)Bu)(3)] [M = Zr (7), Hf (8)]. Tri-tert-butoxystannate may be used as a selective alkoxylating agent for group 4 metals, and it can be transferred to these metals intact if their Lewis acidity is appropriately attenuated as in fac-{M(O(t)Bu)(3)(THF)(3)}. Single-crystal X-ray studies revealed distorted octahedral coordination geometries for all compounds (1-8), with 1, 2, 7, and 8 being crystallographically C(3) symmetric.
三-正丁氧基锡酸酯作为四价金属螯合三齿配体的用途进行了研究。高路易斯酸性的金属通过一系列叔丁氧基消除步骤使锡酸盐离子降解，生成各种四价叔丁氧基化合物。在 THF 溶液中，1 当量的 NaSn(O(t)Bu)(3)与顺式-MCl(4)(THF)(2) [M = Zr (1), Hf (2)]反应，生成盐 fac-{M(O(t)Bu)(3)(THF)(3)}，这是分离的离子对，具有弱配位的三氯代锡酸盐离子。当在这些反应中使用 2/3 当量的氧化锡酸钠时，分离出中性配合物，即[M(O(t)Bu)(2)Cl(2)(THF)(2)] [M = Zr (3), Hf (4)]。四氯化钛既没有形成 1 和 2 的类似物，也没有形成 3 和 4 的类似物，而是 Ti(O(t)Bu)(3)Cl 与三氟甲磺酸银反应生成[Ti(O(t)Bu)(2)(OTf)(2)(THF)(2)] (5)。三氟甲磺酸根阴离子与三氯代锡酸盐阴离子交换得到接触离子对 fac-[Zr(O(t)Bu)(3)OTf(THF)(2)] (6)。2 当量的 NaSn(O(t)Bu)(3)与顺式-MCl(4)(THF)(2)反应生成配合物 fac-[Sn(mu-O(t)Bu)(3)M(O(t)Bu)(3)] [M = Zr (7), Hf (8)]。三-正丁氧基锡酸酯可用作四价金属的选择性烷氧基化试剂，如果它们的路易斯酸度适当减弱，如 fac-{M(O(t)Bu)(3)(THF)(3)}，则可以将其完整地转移到这些金属上。单晶 X 射线研究揭示了所有化合物（1-8）的扭曲八面体配位几何结构，其中 1、2、7 和 8 具有结晶 C(3)对称性。
