標題: Chemistry of Ti(OiPr)Cl-3 with chloride and oxygen-containing ligands: The roles of alkoxide and solvents in the six-coordinate titanium complexes
作者: Gau, HM
Lee, CS
Lin, CC
Jiang, MK
Ho, YC
Kuo, CN
交大名義發表
應用化學系
National Chiao Tung University
Department of Applied Chemistry
公開日期: 27-三月-1996
摘要: Ti((OPr)-Pr-i)Cl-3 reacts easily with various ligands to form a series of six-coordinate complexes, [Ti((OPr)-Pr-i)Cl-5](2-)(HAm+)(2) (Am = NEt(3) (7a) or NC5H5 (7b)), Ti((OPr)-Pr-i)Cl(3)L(2) (L = THF (8) or PhCHO (9)), Ti((OPr)-Pr-i)-Cl-3(PhCHO)(Et(2)O) (10), and [Ti((OPr)-Pr-i)Cl-2(mu-Cl)(PhC(O)OMe)](2) (11). Upon dissolution of 7a in THF, 8 was obtained. When 1 mol equiv of HNEt(3)Cl was added to 8, [Ti((OPr)-Pr-i)Cl-4(THF)](-)(HNEt(3))+ (12) was obtained. With the addition of another 1 mol equiv of HNEt(3)Cl, 12 was converted to 7a. One THF in 8 can be removed in vacuo to give the chloride-bridged dimer [Ti((OPr)-Pr-i)Cl-2(mu-Cl)(THF)](2) (13) which can be converted back to 8 by dissolving in THF. 13 was found to react with 2 mol equiv of HNEt(3)Cl or PhCHO to give 12 and Ti((OPr)-Pr-i)Cl-3(PhCHO)(THF) (14), respectively. The molecular structures of 7b, 8, and 10-13 show short Ti-(OPr)-Pr-i distances, and the relative bonding order of (OPr)-O---Pr-i > Cl-, THF > Et(2)O > PhCHO > mu-Cl- > RC(O)OMe is discussed based on the solid state structures. This bonding sequence is very useful for the prediction of the geometry for six-coordinate complexes of early transition metals with the following principle: The strongest ligand prefers a trans position to the weakest ligand, and the second strongest ligand favors a trans position to the second weakest ligand in the complex. Kinetically, the trans position to the isopropoxide is rather labile for substitution, and the lability of the trans ligand ensures the effectiveness of titanium alkoxides for subsequent reactions or as catalysts in many asymmetric organic syntheses.
URI: http://hdl.handle.net/11536/1395
ISSN: 0002-7863
期刊: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
Volume: 118
Issue: 12
起始頁: 2936
結束頁: 2941
顯示於類別:期刊論文


文件中的檔案:

  1. A1996UC38000018.pdf