Controlled synthesis of a structurally characterized family of sterically constrained heterocyclic alkoxy-modified titanium alkoxides
Controlled synthesis of a structurally characterized family of sterically constrained heterocyclic alkoxy-modified titanium alkoxides
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DOI：
10.1021/ic0618798
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发表时间：
2007-03-05
影响因子：
4.6
通讯作者：
Bunge, Scott D.
中科院分区：
文献类型：
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作者：
Boyle, Timothy J.;Sewell, Robin M.;Bunge, Scott D.
[Ti（mu-ONep）（ONep）（3）]（2）（ONep = OCH 2C（CH 3）（3））与一系列杂环甲醇衍生物[四氢糠醇（H-OTHF）、噻吩甲醇（H-OTPM）或2-吡啶基甲醇（H-OPy），统称为H-OR*]的反应导致分离出OR* 取代的钛醇盐前体的新家族。与H-OTHF反应的初始化学计量无关，分离出一种单取代的双核物质[（ONep）（3）Ti（mu（c）-OTHF）]（2）（1）。对于1，每个Ti通过三个末端ONep配体、一个双齿桥接OTHF配体（mu（c）-OTHF）和来自另一个mu（c）-OTHF配体的氧八面体（Oh）结合。对于OTPM衍生物，产物被鉴定为[（ONep）（3）Ti（mu-OTPM）]（2）（2）。对于该配体，软S原子不结合到Ti，但O原子确实充当两个三角双锥结合的Ti金属中心之间的桥。OPy系统产生（OPy）（2）Ti（OR）（2），与所使用的OR和化学计量无关[OR = ONep（3）、OCHMe 2（4）、OCMe 3（5）]。对于3-5，两个OPy配体用两个末端OR配体螯合到OH结合的Ti金属中心。化合物1-5使用多种分析技术充分表征。初步研究了3-5的“（OPy）（2）Ti”部分对涉及（i）烷基醇、（ii）芳基醇、（iii）取代酚、（iv）H-OR* 衍生物和（v）硅烷醇的醇解交换途径的化学稳定性，通过分离结构表征的（OPy）（2）Ti（OR“）（2）（7-24）化合物的新家族证明是成功的。
The reaction of [Ti(mu-ONep)(ONep)(3)](2) (ONep = OCH2C(CH3)(3)) with a series of heterocyclic methanol derivatives [tetrahydrofurfuryl alcohol (H-OTHF), thiophene methanol (H-OTPM), or 2-pyridylcarbinol (H-OPy)collectively termed H-OR*], led to the isolation of a novel family of OR*-substituted titanium alkoxide precursors. Independent of the initial stoichiometry for the H-OTHF reaction, a monosubstituted, dinuclear species was isolated as [(ONep)(3)Ti(mu(c)-OTHF)](2) (1). For 1, each Ti was octahedrally (Oh) bound by three terminal ONep ligands, one bidentate bridging OTHF ligand (mu(c)-OTHF), and an oxygen from the other mu(c)-OTHF ligand. For the OTPM derivatives, the product was identified as [(ONep)(3)Ti(mu-OTPM)](2) (2). For this ligand, the soft S atom does not bind to the Ti but the O atom does act as a bridge between the two trigonal bipyramidal bound Ti metal centers. The OPy system yielded (OPy)(2)Ti(OR)(2) independent of the OR and the stoichiometry used [OR = ONep (3), OCHMe2 (4), OCMe3 (5)]. For 3-5, the two OPy ligands chelate to the Oh-bound Ti metal center with two terminal OR ligands. Compounds 1-5 were fully characterized using a variety of analytical techniques. An initial investigation of the proposed chemical stability of the '(OPy)(2)Ti' moiety of 3-5 to alcoholysis exchange pathways involving (i) alkyl alcohols, (ii) aryl alcohols, (iii) substituted phenols, (iv) H-OR* derivatives, and (v) silanols proved successful through the isolation of a novel family of structurally characterized (OPy)(2)Ti(OR')(2) (7-24) compounds.